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    <link:label id="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths_9511b1a5-2e3f-4b9c-a16e-aad385c84564_terseLabel_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Operating lease liability payments, due 2021</link:label>
    <link:label id="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths_label_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Lessee, Operating Lease, Liability, to be Paid, Year One</link:label>
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    <link:label id="lab_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract_65340bd1-7a65-4925-a73f-c88e3dd39c70_terseLabel_en-US" xlink:label="lab_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Stockholders&#8217; equity:</link:label>
    <link:label id="lab_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract_label_en-US" xlink:label="lab_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest [Abstract]</link:label>
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    <link:label id="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour_f7f66d2b-326a-4bbf-9a63-1eef0056bcc2_terseLabel_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Operating lease liability payments, due 2024</link:label>
    <link:label id="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour_label_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Lessee, Operating Lease, Liability, to be Paid, Year Four</link:label>
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    <link:label id="lab_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_bd2bc395-3875-479b-8c8f-9d2cbf11e292_terseLabel_en-US" xlink:label="lab_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Unrecognized stock based compensation expense</link:label>
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    <link:label id="lab_sm_SouthTexasMember_e12806e2-9e05-4f49-b328-04d0cb33c0b0_terseLabel_en-US" xlink:label="lab_sm_SouthTexasMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">South Texas [Member]</link:label>
    <link:label id="lab_sm_SouthTexasMember_label_en-US" xlink:label="lab_sm_SouthTexasMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">South Texas [Member]</link:label>
    <link:label id="lab_sm_SouthTexasMember_documentation_en-US" xlink:label="lab_sm_SouthTexasMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">South Texas [Member]</link:label>
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    <link:label id="lab_us-gaap_CurrentStateAndLocalTaxExpenseBenefit_d281de29-6e7b-48ec-b36f-b1feb6933845_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_CurrentStateAndLocalTaxExpenseBenefit" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">State</link:label>
    <link:label id="lab_us-gaap_CurrentStateAndLocalTaxExpenseBenefit_label_en-US" xlink:label="lab_us-gaap_CurrentStateAndLocalTaxExpenseBenefit" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Current State and Local Tax Expense (Benefit)</link:label>
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    <link:label id="lab_us-gaap_HedgingDesignationDomain_2b7487a9-d173-4dcb-991f-ab35fdd82f00_terseLabel_en-US" xlink:label="lab_us-gaap_HedgingDesignationDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Hedging Designation [Domain]</link:label>
    <link:label id="lab_us-gaap_HedgingDesignationDomain_label_en-US" xlink:label="lab_us-gaap_HedgingDesignationDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Hedging Designation [Domain]</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_HedgingDesignationDomain" xlink:to="lab_us-gaap_HedgingDesignationDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_sm_ChangeInCapitalExpendituresIncurredButNotYetPaid_b0a5ecbd-21df-459e-93d6-6c4638e89d6f_terseLabel_en-US" xlink:label="lab_sm_ChangeInCapitalExpendituresIncurredButNotYetPaid" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Increase (decrease) in capital expenditure accruals and other</link:label>
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    <link:label id="lab_us-gaap_LeaseCost_42b9fac4-143d-4643-926e-c301b548e074_terseLabel_en-US" xlink:label="lab_us-gaap_LeaseCost" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Total lease cost</link:label>
    <link:label id="lab_us-gaap_LeaseCost_label_en-US" xlink:label="lab_us-gaap_LeaseCost" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Lease, Cost</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LeaseCost" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LeaseCost"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LeaseCost" xlink:to="lab_us-gaap_LeaseCost" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract_034f5080-75bf-409b-9983-f87fb2acb539_terseLabel_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Other comprehensive income, net of tax:</link:label>
    <link:label id="lab_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract_label_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Other Comprehensive Income (Loss), Net of Tax [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract"/>
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    <link:label id="lab_us-gaap_CommonStockParOrStatedValuePerShare_205c5ffb-3630-4deb-9f3e-f75100fd2838_terseLabel_en-US" xlink:label="lab_us-gaap_CommonStockParOrStatedValuePerShare" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Common Stock, Par or Stated Value Per Share</link:label>
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    <link:label id="lab_us-gaap_GainLossOnSaleOfOilAndGasProperty_10722475-2b5f-4b83-8146-78f28ff2e71d_terseLabel_en-US" xlink:label="lab_us-gaap_GainLossOnSaleOfOilAndGasProperty" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Net gain on divestiture activity</link:label>
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    <link:label id="lab_us-gaap_GainLossOnSaleOfOilAndGasProperty_label_en-US" xlink:label="lab_us-gaap_GainLossOnSaleOfOilAndGasProperty" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Gain (Loss) on Disposition of Oil and Gas Property</link:label>
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    <link:label id="lab_sm_GDWAHAMember_5bfe0995-127f-4a42-9dd2-bac05e305b50_terseLabel_en-US" xlink:label="lab_sm_GDWAHAMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">GD WAHA [Member]</link:label>
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    <link:label id="lab_sm_GDWAHAMember_documentation_en-US" xlink:label="lab_sm_GDWAHAMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">GD WAHA [Member]</link:label>
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    <link:label id="lab_us-gaap_OtherLiabilitiesNoncurrent_ba2dd476-19c9-4936-a79d-e743166944a3_terseLabel_en-US" xlink:label="lab_us-gaap_OtherLiabilitiesNoncurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Other noncurrent liabilities</link:label>
    <link:label id="lab_us-gaap_OtherLiabilitiesNoncurrent_label_en-US" xlink:label="lab_us-gaap_OtherLiabilitiesNoncurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Other Liabilities, Noncurrent</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherLiabilitiesNoncurrent" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherLiabilitiesNoncurrent"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherLiabilitiesNoncurrent" xlink:to="lab_us-gaap_OtherLiabilitiesNoncurrent" xlink:type="arc" order="1"/>
    <link:label id="lab_sm_A5625SeniorUnsecuredNotesDue2025Member_9af8d5af-9fdf-4903-96a0-7a2e6795e9ce_terseLabel_en-US" xlink:label="lab_sm_A5625SeniorUnsecuredNotesDue2025Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">5.625% Senior Unsecured Notes due 2025 [Member]</link:label>
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    <link:label id="lab_us-gaap_DerivativeLiabilitiesNoncurrent_0d6a7d5e-6e97-48cb-a2bc-c61bceb467ee_terseLabel_en-US" xlink:label="lab_us-gaap_DerivativeLiabilitiesNoncurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Derivative liabilities</link:label>
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    <link:label id="lab_dei_EntitySmallBusiness_645868b2-50b3-43fe-981e-5f452c0c8bfe_terseLabel_en-US" xlink:label="lab_dei_EntitySmallBusiness" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Entity Small Business</link:label>
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    <link:label id="lab_us-gaap_OtherOperatingIncomeExpenseNet_c00e3c57-96f6-410c-be16-0904532febae_negatedLabel_en-US" xlink:label="lab_us-gaap_OtherOperatingIncomeExpenseNet" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Other operating expense, net</link:label>
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    <link:label id="lab_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_6203c02d-a6f4-42c3-8a34-3946445e3497_terseLabel_en-US" xlink:label="lab_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Increase (Decrease) in Stockholders' Equity</link:label>
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    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncreaseDecreaseInStockholdersEquityRollForward"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward" xlink:to="lab_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_f8815a4b-3021-467d-ac12-e2b58c1d2669_verboseLabel_en-US" xlink:label="lab_us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Fair Value Hierarchy and NAV [Domain]</link:label>
    <link:label id="lab_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_505c335d-000c-4792-935d-d1febf9228fb_terseLabel_en-US" xlink:label="lab_us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Fair Value Hierarchy and NAV [Domain]</link:label>
    <link:label id="lab_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_label_en-US" xlink:label="lab_us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Fair Value Hierarchy and NAV [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:to="lab_us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_UnamortizedDebtIssuanceExpense_46f873a0-e661-4594-b5a0-cb8d792ff933_terseLabel_en-US" xlink:label="lab_us-gaap_UnamortizedDebtIssuanceExpense" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Revolving Credit Facility, unamortized deferred financing costs</link:label>
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    <link:label id="lab_us-gaap_UnamortizedDebtIssuanceExpense_label_en-US" xlink:label="lab_us-gaap_UnamortizedDebtIssuanceExpense" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Unamortized Debt Issuance Expense</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_UnamortizedDebtIssuanceExpense" xlink:to="lab_us-gaap_UnamortizedDebtIssuanceExpense" xlink:type="arc" order="1"/>
    <link:label id="lab_sm_NYMEXWTIICEBrentMember_68eb67cb-aca0-4155-8e5b-6c8bb1a805a9_terseLabel_en-US" xlink:label="lab_sm_NYMEXWTIICEBrentMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">NYMEX WTI ICE Brent [Member]</link:label>
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    <link:label id="lab_sm_NYMEXWTIICEBrentMember_documentation_en-US" xlink:label="lab_sm_NYMEXWTIICEBrentMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">NYMEX WTI ICE Brent [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sm_NYMEXWTIICEBrentMember" xlink:href="sm-20200930.xsd#sm_NYMEXWTIICEBrentMember"/>
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    <link:label id="lab_us-gaap_ProceedsFromIssuanceOfCommonStock_3cad70c6-1ce7-4466-8445-3bd2c2d1051f_terseLabel_en-US" xlink:label="lab_us-gaap_ProceedsFromIssuanceOfCommonStock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Net proceeds from sale of common stock</link:label>
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    <link:label id="lab_sm_BorrowingBaseUtilizationOf75PercentOrMoreButLessThan90PercentMember_4715214c-e97c-4275-8777-5d083d18624b_terseLabel_en-US" xlink:label="lab_sm_BorrowingBaseUtilizationOf75PercentOrMoreButLessThan90PercentMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Borrowing Base Utilization Of 75 Percent Or More But Less Than 90 Percent [Member]</link:label>
    <link:label id="lab_sm_BorrowingBaseUtilizationOf75PercentOrMoreButLessThan90PercentMember_label_en-US" xlink:label="lab_sm_BorrowingBaseUtilizationOf75PercentOrMoreButLessThan90PercentMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Borrowing Base Utilization Of 75 Percent Or More But Less Than 90 Percent [Member]</link:label>
    <link:label id="lab_sm_BorrowingBaseUtilizationOf75PercentOrMoreButLessThan90PercentMember_documentation_en-US" xlink:label="lab_sm_BorrowingBaseUtilizationOf75PercentOrMoreButLessThan90PercentMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">The borrowing base of 75 percent or more, but less than 90 percent utilized by the entity.</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sm_BorrowingBaseUtilizationOf75PercentOrMoreButLessThan90PercentMember" xlink:to="lab_sm_BorrowingBaseUtilizationOf75PercentOrMoreButLessThan90PercentMember" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_AmendmentFlag_9639b101-5cb3-4862-baff-0d876e0c59b1_terseLabel_en-US" xlink:label="lab_dei_AmendmentFlag" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Amendment Flag</link:label>
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    <link:label id="lab_us-gaap_ScheduleOfEarningsPerShareBasicAndDilutedTableTextBlock_f1c682ba-8afc-42e4-b5f4-fa1fd4c81ac4_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfEarningsPerShareBasicAndDilutedTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule of calculations of basic and diluted net income (loss) per common share [Table Text Block]</link:label>
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    <link:label id="lab_sm_BorrowingBaseUtilizationOf90PercentOrMoreMember_8daa56fc-2082-40eb-a688-360afa12f9b1_terseLabel_en-US" xlink:label="lab_sm_BorrowingBaseUtilizationOf90PercentOrMoreMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Borrowing Base Utilization Of 90 Percent Or More [Member]</link:label>
    <link:label id="lab_sm_BorrowingBaseUtilizationOf90PercentOrMoreMember_label_en-US" xlink:label="lab_sm_BorrowingBaseUtilizationOf90PercentOrMoreMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Borrowing Base Utilization Of 90 Percent Or More [Member]</link:label>
    <link:label id="lab_sm_BorrowingBaseUtilizationOf90PercentOrMoreMember_documentation_en-US" xlink:label="lab_sm_BorrowingBaseUtilizationOf90PercentOrMoreMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">The borrowing base of 90 percent or more utilized by the entity.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sm_BorrowingBaseUtilizationOf90PercentOrMoreMember" xlink:href="sm-20200930.xsd#sm_BorrowingBaseUtilizationOf90PercentOrMoreMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sm_BorrowingBaseUtilizationOf90PercentOrMoreMember" xlink:to="lab_sm_BorrowingBaseUtilizationOf90PercentOrMoreMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant_abebf2a6-a3f7-4e46-9539-17950841ad40_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Shares available for grant</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant" xlink:to="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_OperatingLeasePaymentsUse_2b84f836-5c58-4cff-806c-2c8e69e68f11_terseLabel_en-US" xlink:label="lab_us-gaap_OperatingLeasePaymentsUse" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Investing cash flows from operating leases</link:label>
    <link:label id="lab_us-gaap_OperatingLeasePaymentsUse_label_en-US" xlink:label="lab_us-gaap_OperatingLeasePaymentsUse" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Operating Lease, Payments, Use</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeasePaymentsUse" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OperatingLeasePaymentsUse"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OperatingLeasePaymentsUse" xlink:to="lab_us-gaap_OperatingLeasePaymentsUse" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_NetCashProvidedByUsedInOperatingActivities_088d19c4-07d7-4066-ac87-c5aee4c1171e_totalLabel_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Net cash provided by operating activities</link:label>
    <link:label id="lab_us-gaap_NetCashProvidedByUsedInOperatingActivities_label_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Net Cash Provided by (Used in) Operating Activities</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivities"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:to="lab_us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:type="arc" order="1"/>
    <link:label id="lab_sm_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodMultiplierAssumed_6a108a52-e6a9-44c8-99da-c4dc60acdb3b_terseLabel_en-US" xlink:label="lab_sm_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodMultiplierAssumed" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Multiplier Assumed</link:label>
    <link:label id="lab_sm_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodMultiplierAssumed_label_en-US" xlink:label="lab_sm_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodMultiplierAssumed" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Multiplier Assumed</link:label>
    <link:label id="lab_sm_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodMultiplierAssumed_documentation_en-US" xlink:label="lab_sm_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodMultiplierAssumed" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Multiplier Assumed</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sm_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodMultiplierAssumed" xlink:href="sm-20200930.xsd#sm_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodMultiplierAssumed"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sm_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodMultiplierAssumed" xlink:to="lab_sm_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodMultiplierAssumed" xlink:type="arc" order="1"/>
    <link:label id="lab_sm_AcceleratedUnamortizedDebtDiscountMember_43e96f13-837b-4e6f-85c3-9d689c27bd77_terseLabel_en-US" xlink:label="lab_sm_AcceleratedUnamortizedDebtDiscountMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Accelerated unamortized debt discount [Member]</link:label>
    <link:label id="lab_sm_AcceleratedUnamortizedDebtDiscountMember_label_en-US" xlink:label="lab_sm_AcceleratedUnamortizedDebtDiscountMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Accelerated unamortized debt discount [Member]</link:label>
    <link:label id="lab_sm_AcceleratedUnamortizedDebtDiscountMember_documentation_en-US" xlink:label="lab_sm_AcceleratedUnamortizedDebtDiscountMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Accelerated unamortized debt discount [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sm_AcceleratedUnamortizedDebtDiscountMember" xlink:href="sm-20200930.xsd#sm_AcceleratedUnamortizedDebtDiscountMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sm_AcceleratedUnamortizedDebtDiscountMember" xlink:to="lab_sm_AcceleratedUnamortizedDebtDiscountMember" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_EntityCentralIndexKey_ad3dd471-9b14-4752-a5b4-5af6b9fd0f18_terseLabel_en-US" xlink:label="lab_dei_EntityCentralIndexKey" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Entity Central Index Key</link:label>
    <link:label id="lab_dei_EntityCentralIndexKey_label_en-US" xlink:label="lab_dei_EntityCentralIndexKey" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Entity Central Index Key</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityCentralIndexKey" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_EntityCentralIndexKey"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_EntityCentralIndexKey" xlink:to="lab_dei_EntityCentralIndexKey" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FairValueByMeasurementFrequencyAxis_aca12391-6228-4e39-876c-8fff40135888_verboseLabel_en-US" xlink:label="lab_us-gaap_FairValueByMeasurementFrequencyAxis" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Measurement Frequency [Axis]</link:label>
    <link:label id="lab_us-gaap_FairValueByMeasurementFrequencyAxis_de5711d2-ea20-41a3-afce-626d58f66f56_terseLabel_en-US" xlink:label="lab_us-gaap_FairValueByMeasurementFrequencyAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Measurement Frequency [Axis]</link:label>
    <link:label id="lab_us-gaap_FairValueByMeasurementFrequencyAxis_label_en-US" xlink:label="lab_us-gaap_FairValueByMeasurementFrequencyAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Measurement Frequency [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByMeasurementFrequencyAxis" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueByMeasurementFrequencyAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis" xlink:to="lab_us-gaap_FairValueByMeasurementFrequencyAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity_bd07d877-21a8-4167-948f-0f3c144fb104_terseLabel_en-US" xlink:label="lab_us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Revolving credit facility, current borrowing base</link:label>
    <link:label id="lab_us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity_label_en-US" xlink:label="lab_us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Line of Credit Facility, Current Borrowing Capacity</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity" xlink:to="lab_us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems_85e85683-cb16-4bdf-89bb-c09983e57882_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Defined Benefit Plans [Line Items]</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems" xlink:to="lab_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems" xlink:type="arc" order="1"/>
    <link:label id="lab_sm_MultiplierAppliedToPsuAwardsAtSettlement_255bc27a-2b92-4ab3-97f0-cf89cc56c1a7_terseLabel_en-US" xlink:label="lab_sm_MultiplierAppliedToPsuAwardsAtSettlement" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Multiplier applied to PSU awards at settlement</link:label>
    <link:label id="lab_sm_MultiplierAppliedToPsuAwardsAtSettlement_label_en-US" xlink:label="lab_sm_MultiplierAppliedToPsuAwardsAtSettlement" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Multiplier Applied to PSU Awards at Settlement</link:label>
    <link:label id="lab_sm_MultiplierAppliedToPsuAwardsAtSettlement_documentation_en-US" xlink:label="lab_sm_MultiplierAppliedToPsuAwardsAtSettlement" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">The multiplier applied to the PSU awards at settlement to determine the number of shares of the Company&#8217;s common stock to be issued at the completion of the performance period.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sm_MultiplierAppliedToPsuAwardsAtSettlement" xlink:href="sm-20200930.xsd#sm_MultiplierAppliedToPsuAwardsAtSettlement"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sm_MultiplierAppliedToPsuAwardsAtSettlement" xlink:to="lab_sm_MultiplierAppliedToPsuAwardsAtSettlement" xlink:type="arc" order="1"/>
    <link:label id="lab_sm_DrillingRigLeasingContractsMember_825d0d03-ed10-4931-8a3f-6444bd41db6f_terseLabel_en-US" xlink:label="lab_sm_DrillingRigLeasingContractsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Drilling Rig Leasing Contracts [Member]</link:label>
    <link:label id="lab_sm_DrillingRigLeasingContractsMember_label_en-US" xlink:label="lab_sm_DrillingRigLeasingContractsMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Drilling Rig Leasing Contracts [Member]</link:label>
    <link:label id="lab_sm_DrillingRigLeasingContractsMember_documentation_en-US" xlink:label="lab_sm_DrillingRigLeasingContractsMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Drilling Rig Leasing Contracts [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sm_DrillingRigLeasingContractsMember" xlink:href="sm-20200930.xsd#sm_DrillingRigLeasingContractsMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sm_DrillingRigLeasingContractsMember" xlink:to="lab_sm_DrillingRigLeasingContractsMember" xlink:type="arc" order="1"/>
    <link:label id="lab_sm_AssetAcquisitionLineItems_bd6b4a8a-7d9d-4ab0-b470-dffa937b0c64_terseLabel_en-US" xlink:label="lab_sm_AssetAcquisitionLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Asset Acquisition [Line Items]</link:label>
    <link:label id="lab_sm_AssetAcquisitionLineItems_label_en-US" xlink:label="lab_sm_AssetAcquisitionLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Asset Acquisition [Line Items]</link:label>
    <link:label id="lab_sm_AssetAcquisitionLineItems_documentation_en-US" xlink:label="lab_sm_AssetAcquisitionLineItems" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Asset Acquisition</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sm_AssetAcquisitionLineItems" xlink:href="sm-20200930.xsd#sm_AssetAcquisitionLineItems"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sm_AssetAcquisitionLineItems" xlink:to="lab_sm_AssetAcquisitionLineItems" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DerivativeInstrumentRiskAxis_fcbf824d-df10-4a68-a71a-958a04af314e_terseLabel_en-US" xlink:label="lab_us-gaap_DerivativeInstrumentRiskAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Derivative by Nature [Axis]</link:label>
    <link:label id="lab_us-gaap_DerivativeInstrumentRiskAxis_label_en-US" xlink:label="lab_us-gaap_DerivativeInstrumentRiskAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Derivative Instrument [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis" xlink:to="lab_us-gaap_DerivativeInstrumentRiskAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets_ecd7a2a4-9910-4b20-a90a-e5bc51be67e4_negatedLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Expected return on plan assets that reduces periodic pension benefit cost</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Defined Benefit Plan, Expected Return (Loss) on Plan Assets</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets" xlink:to="lab_us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets" xlink:type="arc" order="1"/>
    <link:label id="lab_sm_AssetAcquisitionTable_b4386af2-67e2-4b5d-9ee3-b101499da857_terseLabel_en-US" xlink:label="lab_sm_AssetAcquisitionTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Asset Acquisition [Table]</link:label>
    <link:label id="lab_sm_AssetAcquisitionTable_label_en-US" xlink:label="lab_sm_AssetAcquisitionTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Asset Acquisition [Table]</link:label>
    <link:label id="lab_sm_AssetAcquisitionTable_documentation_en-US" xlink:label="lab_sm_AssetAcquisitionTable" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Asset Acquisition [Table]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sm_AssetAcquisitionTable" xlink:href="sm-20200930.xsd#sm_AssetAcquisitionTable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sm_AssetAcquisitionTable" xlink:to="lab_sm_AssetAcquisitionTable" xlink:type="arc" order="1"/>
    <link:label id="lab_sm_DebtInstrumentSeniorNotesInitialFairValue_e42f4319-d213-4846-80e8-12b6541292f7_terseLabel_en-US" xlink:label="lab_sm_DebtInstrumentSeniorNotesInitialFairValue" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Debt Instrument, Senior Notes, Initial Fair Value</link:label>
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    <link:label id="lab_srt_StatementGeographicalAxis_b1fbce5d-1a01-43b9-8091-0b42d65fccb9_terseLabel_en-US" xlink:label="lab_srt_StatementGeographicalAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Geographical [Axis]</link:label>
    <link:label id="lab_srt_StatementGeographicalAxis_label_en-US" xlink:label="lab_srt_StatementGeographicalAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Geographical [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_StatementGeographicalAxis" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_StatementGeographicalAxis"/>
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    <link:label id="lab_sm_A6625SeniorUnsecuredNotesDue2027Member_0574e09a-e387-4708-bb6a-81498d815935_terseLabel_en-US" xlink:label="lab_sm_A6625SeniorUnsecuredNotesDue2027Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">6.625% Senior Unsecured Notes due 2027 [Member]</link:label>
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    <link:label id="lab_sm_GasSwapsContractYear2Member_ca24ab1a-2009-4a89-b92f-4947eab64e1d_terseLabel_en-US" xlink:label="lab_sm_GasSwapsContractYear2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Gas Swaps Contract, 2021 [Member]</link:label>
    <link:label id="lab_sm_GasSwapsContractYear2Member_label_en-US" xlink:label="lab_sm_GasSwapsContractYear2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Gas Swaps Contract, Year 2 [Member]</link:label>
    <link:label id="lab_sm_GasSwapsContractYear2Member_documentation_en-US" xlink:label="lab_sm_GasSwapsContractYear2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Gas Swaps Contract, Year 2 [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sm_GasSwapsContractYear2Member" xlink:href="sm-20200930.xsd#sm_GasSwapsContractYear2Member"/>
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    <link:label id="lab_us-gaap_EarlyRepaymentOfSeniorDebt_5d59857a-40a2-4a5f-8e86-2f7fd9f947f0_negatedLabel_en-US" xlink:label="lab_us-gaap_EarlyRepaymentOfSeniorDebt" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Cash paid to repurchase Senior Notes</link:label>
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    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarlyRepaymentOfSeniorDebt" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EarlyRepaymentOfSeniorDebt"/>
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    <link:label id="lab_us-gaap_LesseeOperatingLeaseRenewalTerm_d1f589f5-a9c9-4659-afd4-cb16beee8cbf_terseLabel_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeaseRenewalTerm" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Optional extension period</link:label>
    <link:label id="lab_us-gaap_LesseeOperatingLeaseRenewalTerm_label_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeaseRenewalTerm" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Lessee, Operating Lease, Renewal Term</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LesseeOperatingLeaseRenewalTerm" xlink:to="lab_us-gaap_LesseeOperatingLeaseRenewalTerm" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_StatementOfCashFlowsAbstract_04552fc2-67a4-4a34-99cb-667b584d271b_terseLabel_en-US" xlink:label="lab_us-gaap_StatementOfCashFlowsAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Statement of Cash Flows [Abstract]</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StatementOfCashFlowsAbstract" xlink:to="lab_us-gaap_StatementOfCashFlowsAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_sm_PensionAndOtherPostRetirementBenefitPlansGainLossAmortizationThreshold_d920dd75-a560-4696-ba91-830cd328c844_terseLabel_en-US" xlink:label="lab_sm_PensionAndOtherPostRetirementBenefitPlansGainLossAmortizationThreshold" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Pension plans, net gain (loss) amortization threshold</link:label>
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    <link:label id="lab_sm_PensionAndOtherPostRetirementBenefitPlansGainLossAmortizationThreshold_documentation_en-US" xlink:label="lab_sm_PensionAndOtherPostRetirementBenefitPlansGainLossAmortizationThreshold" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Gain and loses in excess of 10% of the greater of the projected benefit obligation or fari value of plan assets will be amortized over the average remaining service period</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sm_PensionAndOtherPostRetirementBenefitPlansGainLossAmortizationThreshold" xlink:href="sm-20200930.xsd#sm_PensionAndOtherPostRetirementBenefitPlansGainLossAmortizationThreshold"/>
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    <link:label id="lab_us-gaap_ScheduleOfLineOfCreditFacilitiesTextBlock_25ac9ac9-2857-4988-b6ec-935c039180f6_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfLineOfCreditFacilitiesTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule of Line of Credit Facilities [Table Text Block]</link:label>
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    <link:label id="lab_us-gaap_InterestCostsCapitalized_979bf706-8c87-498e-ab36-c6ccb9a71b68_terseLabel_en-US" xlink:label="lab_us-gaap_InterestCostsCapitalized" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Capitalized interest costs</link:label>
    <link:label id="lab_us-gaap_InterestCostsCapitalized_label_en-US" xlink:label="lab_us-gaap_InterestCostsCapitalized" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Interest Costs Capitalized</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestCostsCapitalized" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InterestCostsCapitalized"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_InterestCostsCapitalized" xlink:to="lab_us-gaap_InterestCostsCapitalized" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_EntityCommonStockSharesOutstanding_6569fecd-6d1c-4655-bd8a-4affc66e56c8_terseLabel_en-US" xlink:label="lab_dei_EntityCommonStockSharesOutstanding" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Entity Common Stock, Shares Outstanding</link:label>
    <link:label id="lab_dei_EntityCommonStockSharesOutstanding_label_en-US" xlink:label="lab_dei_EntityCommonStockSharesOutstanding" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Entity Common Stock, Shares Outstanding</link:label>
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    <link:label id="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo_5cba25b0-e14f-488b-8f45-e4610248f25e_terseLabel_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Operating lease liability payments, due 2022</link:label>
    <link:label id="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo_label_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Lessee, Operating Lease, Liability, to be Paid, Year Two</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo" xlink:to="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_OtherCommitmentsLineItems_bfb7285e-ba4f-486d-bc88-0a2bae0aaf94_terseLabel_en-US" xlink:label="lab_us-gaap_OtherCommitmentsLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Commitments and Contingencies [Line Items]</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherCommitmentsLineItems" xlink:to="lab_us-gaap_OtherCommitmentsLineItems" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_CurrentFederalTaxExpenseBenefit_92e9eb16-c1af-4949-ad8a-b41f26e24f54_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_CurrentFederalTaxExpenseBenefit" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Federal</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CurrentFederalTaxExpenseBenefit" xlink:to="lab_us-gaap_CurrentFederalTaxExpenseBenefit" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LeaseCostTableTextBlock_1f4084d2-62af-4fb4-b8d8-d2947e4b5b76_terseLabel_en-US" xlink:label="lab_us-gaap_LeaseCostTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Components of total lease cost [Table Text Block]</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LeaseCostTableTextBlock" xlink:to="lab_us-gaap_LeaseCostTableTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LineOfCreditFacilityTable_0d2e4aa6-6f92-4ee9-9111-2d0bdc057347_terseLabel_en-US" xlink:label="lab_us-gaap_LineOfCreditFacilityTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Line of Credit Facility [Table]</link:label>
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    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityTable" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LineOfCreditFacilityTable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LineOfCreditFacilityTable" xlink:to="lab_us-gaap_LineOfCreditFacilityTable" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DerivativeFairValueOfDerivativeNet_59dcd921-c784-4fb6-9ef7-49bdd9ab829d_terseLabel_en-US" xlink:label="lab_us-gaap_DerivativeFairValueOfDerivativeNet" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Derivative, fair value, net</link:label>
    <link:label id="lab_us-gaap_DerivativeFairValueOfDerivativeNet_label_en-US" xlink:label="lab_us-gaap_DerivativeFairValueOfDerivativeNet" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Derivative, Fair Value, Net</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeFairValueOfDerivativeNet" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeFairValueOfDerivativeNet"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DerivativeFairValueOfDerivativeNet" xlink:to="lab_us-gaap_DerivativeFairValueOfDerivativeNet" xlink:type="arc" order="1"/>
    <link:label id="lab_sm_OilBasisSwapMember_c7d7e560-4f4c-42b8-b385-cccbc000d26b_terseLabel_en-US" xlink:label="lab_sm_OilBasisSwapMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Oil Basis Swap [Member]</link:label>
    <link:label id="lab_sm_OilBasisSwapMember_label_en-US" xlink:label="lab_sm_OilBasisSwapMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Oil Basis Swap [Member]</link:label>
    <link:label id="lab_sm_OilBasisSwapMember_documentation_en-US" xlink:label="lab_sm_OilBasisSwapMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Oil Basis Swap [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sm_OilBasisSwapMember" xlink:href="sm-20200930.xsd#sm_OilBasisSwapMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sm_OilBasisSwapMember" xlink:to="lab_sm_OilBasisSwapMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree_0cb44936-b99b-4254-bc07-194e4b8727d2_terseLabel_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Operating lease liability payments, due 2023</link:label>
    <link:label id="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree_label_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Lessee, Operating Lease, Liability, to be Paid, Year Three</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree"/>
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    <link:label id="lab_us-gaap_OtherAssetsNoncurrent_a8174e07-541b-4711-895a-93c9991dfc59_terseLabel_en-US" xlink:label="lab_us-gaap_OtherAssetsNoncurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Other noncurrent assets</link:label>
    <link:label id="lab_us-gaap_OtherAssetsNoncurrent_label_en-US" xlink:label="lab_us-gaap_OtherAssetsNoncurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Other Assets, Noncurrent</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAssetsNoncurrent" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherAssetsNoncurrent"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherAssetsNoncurrent" xlink:to="lab_us-gaap_OtherAssetsNoncurrent" xlink:type="arc" order="1"/>
    <link:label id="lab_sm_GasSwapsContractsMember_746e372d-9db0-4019-95c3-9f63e3c3abd5_terseLabel_en-US" xlink:label="lab_sm_GasSwapsContractsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Gas Swaps Contracts [Member]</link:label>
    <link:label id="lab_sm_GasSwapsContractsMember_label_en-US" xlink:label="lab_sm_GasSwapsContractsMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Gas Swaps Contracts [Member]</link:label>
    <link:label id="lab_sm_GasSwapsContractsMember_documentation_en-US" xlink:label="lab_sm_GasSwapsContractsMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Gas Swaps Contracts [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sm_GasSwapsContractsMember" xlink:href="sm-20200930.xsd#sm_GasSwapsContractsMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sm_GasSwapsContractsMember" xlink:to="lab_sm_GasSwapsContractsMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_PlanNameAxis_605c7e39-417e-46a0-aef5-ba3d4bb17ed0_terseLabel_en-US" xlink:label="lab_us-gaap_PlanNameAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Plan Name [Axis]</link:label>
    <link:label id="lab_us-gaap_PlanNameAxis_label_en-US" xlink:label="lab_us-gaap_PlanNameAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Plan Name [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameAxis" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PlanNameAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PlanNameAxis" xlink:to="lab_us-gaap_PlanNameAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_sm_NYMEXOilCollarContractYear2Member_1f8f0c38-1335-4239-940f-abf41f3dcc27_terseLabel_en-US" xlink:label="lab_sm_NYMEXOilCollarContractYear2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">NYMEX Oil Collar Contract, 2021 [Member]</link:label>
    <link:label id="lab_sm_NYMEXOilCollarContractYear2Member_label_en-US" xlink:label="lab_sm_NYMEXOilCollarContractYear2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">NYMEX Oil Collar Contract, Year 2 [Member]</link:label>
    <link:label id="lab_sm_NYMEXOilCollarContractYear2Member_documentation_en-US" xlink:label="lab_sm_NYMEXOilCollarContractYear2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">NYMEX Oil Collar Contract, Year 2 [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sm_NYMEXOilCollarContractYear2Member" xlink:href="sm-20200930.xsd#sm_NYMEXOilCollarContractYear2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sm_NYMEXOilCollarContractYear2Member" xlink:to="lab_sm_NYMEXOilCollarContractYear2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_IncrementalCommonSharesAttributableToCallOptionsAndWarrants_856d17a6-73c6-4b87-9a91-473184b6fab8_terseLabel_en-US" xlink:label="lab_us-gaap_IncrementalCommonSharesAttributableToCallOptionsAndWarrants" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Incremental Common Shares Attributable to Dilutive Effect of Warrants</link:label>
    <link:label id="lab_us-gaap_IncrementalCommonSharesAttributableToCallOptionsAndWarrants_label_en-US" xlink:label="lab_us-gaap_IncrementalCommonSharesAttributableToCallOptionsAndWarrants" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Incremental Common Shares Attributable to Dilutive Effect of Call Options and Warrants</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncrementalCommonSharesAttributableToCallOptionsAndWarrants" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncrementalCommonSharesAttributableToCallOptionsAndWarrants"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncrementalCommonSharesAttributableToCallOptionsAndWarrants" xlink:to="lab_us-gaap_IncrementalCommonSharesAttributableToCallOptionsAndWarrants" xlink:type="arc" order="1"/>
    <link:label id="lab_sm_OilBasisSwapContractYear2Member_5ed2433f-bdb9-4ea6-8950-9419e0d8ad0a_terseLabel_en-US" xlink:label="lab_sm_OilBasisSwapContractYear2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Oil Basis Swap Contract, 2021 [Member]</link:label>
    <link:label id="lab_sm_OilBasisSwapContractYear2Member_label_en-US" xlink:label="lab_sm_OilBasisSwapContractYear2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Oil Basis Swap Contract, Year 2 [Member]</link:label>
    <link:label id="lab_sm_OilBasisSwapContractYear2Member_documentation_en-US" xlink:label="lab_sm_OilBasisSwapContractYear2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Oil Basis Swap Contract, Year 2 [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sm_OilBasisSwapContractYear2Member" xlink:href="sm-20200930.xsd#sm_OilBasisSwapContractYear2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sm_OilBasisSwapContractYear2Member" xlink:to="lab_sm_OilBasisSwapContractYear2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_Assets_bfed4ea9-9848-4bf1-9df9-bdc7f7e79ba6_totalLabel_en-US" xlink:label="lab_us-gaap_Assets" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Total assets</link:label>
    <link:label id="lab_us-gaap_Assets_label_en-US" xlink:label="lab_us-gaap_Assets" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Assets</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Assets" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_Assets"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_Assets" xlink:to="lab_us-gaap_Assets" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DerivativeLiabilitiesCurrent_2bf3f095-1ac8-47a9-b01d-0c96f2111a12_terseLabel_en-US" xlink:label="lab_us-gaap_DerivativeLiabilitiesCurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Derivative liabilities</link:label>
    <link:label id="lab_us-gaap_DerivativeLiabilitiesCurrent_8f3cc553-6a25-4e1a-854c-62624dc40ab6_verboseLabel_en-US" xlink:label="lab_us-gaap_DerivativeLiabilitiesCurrent" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Derivative liabilities, current</link:label>
    <link:label id="lab_us-gaap_DerivativeLiabilitiesCurrent_label_en-US" xlink:label="lab_us-gaap_DerivativeLiabilitiesCurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Derivative Liability, Current</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLiabilitiesCurrent" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeLiabilitiesCurrent"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DerivativeLiabilitiesCurrent" xlink:to="lab_us-gaap_DerivativeLiabilitiesCurrent" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_InterestExpenseDebt_7372c82a-dc13-4c42-b0b3-5e82d78d24c5_terseLabel_en-US" xlink:label="lab_us-gaap_InterestExpenseDebt" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Interest Expense, Debt</link:label>
    <link:label id="lab_us-gaap_InterestExpenseDebt_label_en-US" xlink:label="lab_us-gaap_InterestExpenseDebt" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Interest Expense, Debt</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpenseDebt" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InterestExpenseDebt"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_InterestExpenseDebt" xlink:to="lab_us-gaap_InterestExpenseDebt" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_OrganizationConsolidationBasisOfPresentationBusinessDescriptionAndAccountingPoliciesTextBlock_91276a85-48bc-4204-b247-f5f216763866_terseLabel_en-US" xlink:label="lab_us-gaap_OrganizationConsolidationBasisOfPresentationBusinessDescriptionAndAccountingPoliciesTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Summary of Significant Accounting Policies</link:label>
    <link:label id="lab_us-gaap_OrganizationConsolidationBasisOfPresentationBusinessDescriptionAndAccountingPoliciesTextBlock_label_en-US" xlink:label="lab_us-gaap_OrganizationConsolidationBasisOfPresentationBusinessDescriptionAndAccountingPoliciesTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Organization, Consolidation, Basis of Presentation, Business Description and Accounting Policies [Text Block]</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OrganizationConsolidationBasisOfPresentationBusinessDescriptionAndAccountingPoliciesTextBlock" xlink:to="lab_us-gaap_OrganizationConsolidationBasisOfPresentationBusinessDescriptionAndAccountingPoliciesTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AssetsNoncurrentOtherThanNoncurrentInvestmentsAndPropertyPlantAndEquipment_dbb2b056-d668-4a55-8e68-cb45041482ef_totalLabel_en-US" xlink:label="lab_us-gaap_AssetsNoncurrentOtherThanNoncurrentInvestmentsAndPropertyPlantAndEquipment" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Total noncurrent assets</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AssetsNoncurrentOtherThanNoncurrentInvestmentsAndPropertyPlantAndEquipment" xlink:to="lab_us-gaap_AssetsNoncurrentOtherThanNoncurrentInvestmentsAndPropertyPlantAndEquipment" xlink:type="arc" order="1"/>
    <link:label id="lab_sm_DerivativeCalendarMonthAverageRollDifferentialSwapTypeWeightedAverageContractPrice_2e50970e-795d-449b-890c-b170949c4b50_terseLabel_en-US" xlink:label="lab_sm_DerivativeCalendarMonthAverageRollDifferentialSwapTypeWeightedAverageContractPrice" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Derivative, Roll Differential Swap Type, Weighted-Average Contract Price</link:label>
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    <link:label id="lab_sm_DerivativeCalendarMonthAverageRollDifferentialSwapTypeWeightedAverageContractPrice_documentation_en-US" xlink:label="lab_sm_DerivativeCalendarMonthAverageRollDifferentialSwapTypeWeightedAverageContractPrice" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Derivative, Calendar Month Average Roll Differential Swap Type, Weighted-Average Contract Price</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sm_DerivativeCalendarMonthAverageRollDifferentialSwapTypeWeightedAverageContractPrice" xlink:href="sm-20200930.xsd#sm_DerivativeCalendarMonthAverageRollDifferentialSwapTypeWeightedAverageContractPrice"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sm_DerivativeCalendarMonthAverageRollDifferentialSwapTypeWeightedAverageContractPrice" xlink:to="lab_sm_DerivativeCalendarMonthAverageRollDifferentialSwapTypeWeightedAverageContractPrice" xlink:type="arc" order="1"/>
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    <link:label id="lab_us-gaap_InterestExpense_79d0b8d7-6b15-4fb9-92b9-e5df0d398799_negatedLabel_en-US" xlink:label="lab_us-gaap_InterestExpense" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Interest expense</link:label>
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    <link:label id="lab_srt_ProductOrServiceAxis_073edd7f-267a-4520-baa3-f7b7ed91d2c8_terseLabel_en-US" xlink:label="lab_srt_ProductOrServiceAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Product and Service [Axis]</link:label>
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    <link:label id="lab_sm_NGLContractsMember_0074a20d-6a0e-468a-9c88-c21b1a13d7e9_terseLabel_en-US" xlink:label="lab_sm_NGLContractsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">NGL Contracts [Member]</link:label>
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    <link:label id="lab_us-gaap_PropertyPlantAndEquipmentFairValueDisclosure_99344a4f-ffb8-4664-a99d-efb4ae8e5b77_terseLabel_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentFairValueDisclosure" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Total property and equipment, net, recorded at fair value</link:label>
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    <link:label id="lab_us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount_f7f44d79-7743-4490-b8e6-414ad2d5c6c1_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Imputed interest</link:label>
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    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember" xlink:to="lab_us-gaap_AccumulatedOtherComprehensiveIncomeMember" xlink:type="arc" order="1"/>
    <link:label id="lab_sm_NonmonetaryTradeAcreageExchanged_9e5e321e-a8c6-44ea-8dff-c2d3fb2ea7dd_terseLabel_en-US" xlink:label="lab_sm_NonmonetaryTradeAcreageExchanged" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Non-monetary Trade, Acreage Exchanged</link:label>
    <link:label id="lab_sm_NonmonetaryTradeAcreageExchanged_label_en-US" xlink:label="lab_sm_NonmonetaryTradeAcreageExchanged" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Non-monetary Trade, Acreage Exchanged</link:label>
    <link:label id="lab_sm_NonmonetaryTradeAcreageExchanged_documentation_en-US" xlink:label="lab_sm_NonmonetaryTradeAcreageExchanged" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Acreage exchanged through non-monetary trades.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sm_NonmonetaryTradeAcreageExchanged" xlink:href="sm-20200930.xsd#sm_NonmonetaryTradeAcreageExchanged"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sm_NonmonetaryTradeAcreageExchanged" xlink:to="lab_sm_NonmonetaryTradeAcreageExchanged" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_OperatingLeaseLiabilityNoncurrent_8214dfab-2704-456f-90b2-6113d01bad80_terseLabel_en-US" xlink:label="lab_us-gaap_OperatingLeaseLiabilityNoncurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Other noncurrent liabilities</link:label>
    <link:label id="lab_us-gaap_OperatingLeaseLiabilityNoncurrent_label_en-US" xlink:label="lab_us-gaap_OperatingLeaseLiabilityNoncurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Operating Lease, Liability, Noncurrent</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLiabilityNoncurrent" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OperatingLeaseLiabilityNoncurrent"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OperatingLeaseLiabilityNoncurrent" xlink:to="lab_us-gaap_OperatingLeaseLiabilityNoncurrent" xlink:type="arc" order="1"/>
    <link:label id="lab_sm_PermittedSecondLienDebt_d0a9072d-bad8-4924-98c4-858eee38dbb6_terseLabel_en-US" xlink:label="lab_sm_PermittedSecondLienDebt" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Permitted Second Lien Debt</link:label>
    <link:label id="lab_sm_PermittedSecondLienDebt_label_en-US" xlink:label="lab_sm_PermittedSecondLienDebt" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Permitted Second Lien Debt</link:label>
    <link:label id="lab_sm_PermittedSecondLienDebt_documentation_en-US" xlink:label="lab_sm_PermittedSecondLienDebt" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Permitted Second Lien Debt</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sm_PermittedSecondLienDebt" xlink:href="sm-20200930.xsd#sm_PermittedSecondLienDebt"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sm_PermittedSecondLienDebt" xlink:to="lab_sm_PermittedSecondLienDebt" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_44961fef-61c8-4cd1-bec8-ac6a252cf602_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule of Segment Reporting Information, by Segment [Table]</link:label>
    <link:label id="lab_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_label_en-US" xlink:label="lab_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule of Segment Reporting Information, by Segment [Table]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable" xlink:to="lab_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AssetsCurrentAbstract_03f4731f-154f-4894-b619-21f5f81d0360_terseLabel_en-US" xlink:label="lab_us-gaap_AssetsCurrentAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Current assets:</link:label>
    <link:label id="lab_us-gaap_AssetsCurrentAbstract_label_en-US" xlink:label="lab_us-gaap_AssetsCurrentAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Assets, Current [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsCurrentAbstract" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AssetsCurrentAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AssetsCurrentAbstract" xlink:to="lab_us-gaap_AssetsCurrentAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperationsAbstract_f2fc8d1a-f540-470a-a2b5-1e09ae639e8b_terseLabel_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperationsAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Cash flows from investing activities:</link:label>
    <link:label id="lab_us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperationsAbstract_label_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperationsAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Net Cash Provided by (Used in) Investing Activities, Continuing Operations [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperationsAbstract" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperationsAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperationsAbstract" xlink:to="lab_us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperationsAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DerivativeNonmonetaryNotionalAmountVolume_bcfda7c7-2f3b-4b65-98fb-69eb718ba06e_terseLabel_en-US" xlink:label="lab_us-gaap_DerivativeNonmonetaryNotionalAmountVolume" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Derivative, Nonmonetary Notional Amount, Volume</link:label>
    <link:label id="lab_us-gaap_DerivativeNonmonetaryNotionalAmountVolume_label_en-US" xlink:label="lab_us-gaap_DerivativeNonmonetaryNotionalAmountVolume" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Derivative, Nonmonetary Notional Amount, Volume</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeNonmonetaryNotionalAmountVolume" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeNonmonetaryNotionalAmountVolume"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DerivativeNonmonetaryNotionalAmountVolume" xlink:to="lab_us-gaap_DerivativeNonmonetaryNotionalAmountVolume" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ExplorationExpense_daf22391-e4d2-4596-a872-7a4626b8c134_terseLabel_en-US" xlink:label="lab_us-gaap_ExplorationExpense" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Exploration</link:label>
    <link:label id="lab_us-gaap_ExplorationExpense_label_en-US" xlink:label="lab_us-gaap_ExplorationExpense" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Exploration Expense</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ExplorationExpense" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ExplorationExpense"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ExplorationExpense" xlink:to="lab_us-gaap_ExplorationExpense" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ComprehensiveIncomeNetOfTax_56e39cb0-add8-45c6-91fe-9a04965b1072_totalLabel_en-US" xlink:label="lab_us-gaap_ComprehensiveIncomeNetOfTax" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Total comprehensive income (loss)</link:label>
    <link:label id="lab_us-gaap_ComprehensiveIncomeNetOfTax_label_en-US" xlink:label="lab_us-gaap_ComprehensiveIncomeNetOfTax" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Comprehensive Income (Loss), Net of Tax, Attributable to Parent</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ComprehensiveIncomeNetOfTax" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ComprehensiveIncomeNetOfTax"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ComprehensiveIncomeNetOfTax" xlink:to="lab_us-gaap_ComprehensiveIncomeNetOfTax" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LongTermLineOfCredit_b22b2019-d63f-4ebb-8540-c222c837fc00_terseLabel_en-US" xlink:label="lab_us-gaap_LongTermLineOfCredit" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Revolving credit facility</link:label>
    <link:label id="lab_us-gaap_LongTermLineOfCredit_label_en-US" xlink:label="lab_us-gaap_LongTermLineOfCredit" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Long-term Line of Credit, Noncurrent</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermLineOfCredit" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LongTermLineOfCredit"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LongTermLineOfCredit" xlink:to="lab_us-gaap_LongTermLineOfCredit" xlink:type="arc" order="1"/>
    <link:label id="lab_sm_WarrantTriggeringDateAmount_95adbc70-2bc0-4476-9b67-00d76a7b7a98_terseLabel_en-US" xlink:label="lab_sm_WarrantTriggeringDateAmount" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Warrant Triggering Date - Amount</link:label>
    <link:label id="lab_sm_WarrantTriggeringDateAmount_label_en-US" xlink:label="lab_sm_WarrantTriggeringDateAmount" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Warrant Triggering Date - Amount</link:label>
    <link:label id="lab_sm_WarrantTriggeringDateAmount_documentation_en-US" xlink:label="lab_sm_WarrantTriggeringDateAmount" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Warrant Triggering Date - Amount</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sm_WarrantTriggeringDateAmount" xlink:href="sm-20200930.xsd#sm_WarrantTriggeringDateAmount"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sm_WarrantTriggeringDateAmount" xlink:to="lab_sm_WarrantTriggeringDateAmount" xlink:type="arc" order="1"/>
    <link:label id="lab_sm_NYMEXOilCollarContractFourthQuarterYear1Member_135b820e-c514-454e-9f0a-fb52d3e973f0_terseLabel_en-US" xlink:label="lab_sm_NYMEXOilCollarContractFourthQuarterYear1Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">NYMEX Oil Collar Contract Fourth Quarter, 2020 [Member]</link:label>
    <link:label id="lab_sm_NYMEXOilCollarContractFourthQuarterYear1Member_label_en-US" xlink:label="lab_sm_NYMEXOilCollarContractFourthQuarterYear1Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">NYMEX Oil Collar Contract Fourth Quarter, Year 1 [Member]</link:label>
    <link:label id="lab_sm_NYMEXOilCollarContractFourthQuarterYear1Member_documentation_en-US" xlink:label="lab_sm_NYMEXOilCollarContractFourthQuarterYear1Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">NYMEX Oil Collar Contract Fourth Quarter, Year 1 [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sm_NYMEXOilCollarContractFourthQuarterYear1Member" xlink:href="sm-20200930.xsd#sm_NYMEXOilCollarContractFourthQuarterYear1Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sm_NYMEXOilCollarContractFourthQuarterYear1Member" xlink:to="lab_sm_NYMEXOilCollarContractFourthQuarterYear1Member" xlink:type="arc" order="1"/>
    <link:label id="lab_sm_PotentialPenaltyfornotMeetingMinimumDrillingandCompletionRequirements_1f187a21-b9cb-4e45-a67d-b43bee1b0487_terseLabel_en-US" xlink:label="lab_sm_PotentialPenaltyfornotMeetingMinimumDrillingandCompletionRequirements" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Potential penalty for not meeting minimum drilling and completion requirements</link:label>
    <link:label id="lab_sm_PotentialPenaltyfornotMeetingMinimumDrillingandCompletionRequirements_label_en-US" xlink:label="lab_sm_PotentialPenaltyfornotMeetingMinimumDrillingandCompletionRequirements" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Potential Penalty for not Meeting Minimum Drilling and Completion Requirements</link:label>
    <link:label id="lab_sm_PotentialPenaltyfornotMeetingMinimumDrillingandCompletionRequirements_documentation_en-US" xlink:label="lab_sm_PotentialPenaltyfornotMeetingMinimumDrillingandCompletionRequirements" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Potential Penalty for not Meeting Minimum Drilling and Completion Requirements</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sm_PotentialPenaltyfornotMeetingMinimumDrillingandCompletionRequirements" xlink:href="sm-20200930.xsd#sm_PotentialPenaltyfornotMeetingMinimumDrillingandCompletionRequirements"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sm_PotentialPenaltyfornotMeetingMinimumDrillingandCompletionRequirements" xlink:to="lab_sm_PotentialPenaltyfornotMeetingMinimumDrillingandCompletionRequirements" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ScheduleOfNonvestedPerformanceBasedUnitsActivityTableTextBlock_8052ad2e-fbfe-4d5b-a77b-10bad62e4999_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfNonvestedPerformanceBasedUnitsActivityTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule of non-vested PSUs</link:label>
    <link:label id="lab_us-gaap_ScheduleOfNonvestedPerformanceBasedUnitsActivityTableTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfNonvestedPerformanceBasedUnitsActivityTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule of Nonvested Performance-based Units Activity [Table Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfNonvestedPerformanceBasedUnitsActivityTableTextBlock" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfNonvestedPerformanceBasedUnitsActivityTableTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfNonvestedPerformanceBasedUnitsActivityTableTextBlock" xlink:to="lab_us-gaap_ScheduleOfNonvestedPerformanceBasedUnitsActivityTableTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DerivativeSwapTypeAverageFixedPrice_73e1f89c-cd96-4807-9fe6-7c01f7053cc0_terseLabel_en-US" xlink:label="lab_us-gaap_DerivativeSwapTypeAverageFixedPrice" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Derivative, Swap Type, Weighted-Average Contract Price</link:label>
    <link:label id="lab_us-gaap_DerivativeSwapTypeAverageFixedPrice_label_en-US" xlink:label="lab_us-gaap_DerivativeSwapTypeAverageFixedPrice" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Derivative, Swap Type, Average Fixed Price</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeSwapTypeAverageFixedPrice" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeSwapTypeAverageFixedPrice"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DerivativeSwapTypeAverageFixedPrice" xlink:to="lab_us-gaap_DerivativeSwapTypeAverageFixedPrice" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_CityAreaCode_6082b735-660f-44f8-9d2d-a8648c799cd0_terseLabel_en-US" xlink:label="lab_dei_CityAreaCode" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">City Area Code</link:label>
    <link:label id="lab_dei_CityAreaCode_label_en-US" xlink:label="lab_dei_CityAreaCode" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">City Area Code</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_CityAreaCode" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_CityAreaCode"/>
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    <link:label id="lab_us-gaap_CostsAndExpenses_fdcf9bc0-5f15-40b1-b455-1359de645171_totalLabel_en-US" xlink:label="lab_us-gaap_CostsAndExpenses" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Total operating expenses</link:label>
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    <link:label id="lab_us-gaap_StatementEquityComponentsAxis_0bffc376-3a3e-4a55-a3f2-09e190edef74_terseLabel_en-US" xlink:label="lab_us-gaap_StatementEquityComponentsAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Equity Components [Axis]</link:label>
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    <link:label id="lab_sm_DebtInstrumentBorrowingBaseUtilizationPercentageDomain_documentation_en-US" xlink:label="lab_sm_DebtInstrumentBorrowingBaseUtilizationPercentageDomain" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">The different utilization percentages of the borrowing base available to the entity.</link:label>
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    <link:label id="lab_us-gaap_DebtInstrumentRepurchasedFaceAmount_9da28995-3c4c-4891-a67f-e07d34b621a9_terseLabel_en-US" xlink:label="lab_us-gaap_DebtInstrumentRepurchasedFaceAmount" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Senior Unsecured Notes, exchanged or repurchased face amount</link:label>
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    <link:label id="lab_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_9bde83eb-6732-4f7a-902b-f9124d784b92_terseLabel_en-US" xlink:label="lab_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Share-based Payment Arrangement [Abstract]</link:label>
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    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract"/>
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    <link:label id="lab_us-gaap_DebtInstrumentNameDomain_1b39008a-d14d-4d57-959d-21a119f13514_terseLabel_en-US" xlink:label="lab_us-gaap_DebtInstrumentNameDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Debt Instrument, Name [Domain]</link:label>
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    <link:label id="lab_srt_MinimumMember_19e6f556-f0ec-4685-a064-ca776d2a653a_terseLabel_en-US" xlink:label="lab_srt_MinimumMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Minimum [Member]</link:label>
    <link:label id="lab_srt_MinimumMember_label_en-US" xlink:label="lab_srt_MinimumMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Minimum [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MinimumMember"/>
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    <link:label id="lab_sm_WarrantsPercentOfOutstandingStock_56fff386-7473-4841-9821-2233eefaf674_terseLabel_en-US" xlink:label="lab_sm_WarrantsPercentOfOutstandingStock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Warrants Percent of Outstanding Stock</link:label>
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    <link:label id="lab_sm_WarrantsPercentOfOutstandingStock_documentation_en-US" xlink:label="lab_sm_WarrantsPercentOfOutstandingStock" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Warrants Percent of Outstanding Stock</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sm_WarrantsPercentOfOutstandingStock" xlink:href="sm-20200930.xsd#sm_WarrantsPercentOfOutstandingStock"/>
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    <link:label id="lab_us-gaap_OperatingLeaseLiabilityCurrent_191d00a2-f5a0-4d5d-b3c8-482540078aae_terseLabel_en-US" xlink:label="lab_us-gaap_OperatingLeaseLiabilityCurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Other current liabilities</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OperatingLeaseLiabilityCurrent" xlink:to="lab_us-gaap_OperatingLeaseLiabilityCurrent" xlink:type="arc" order="1"/>
    <link:label id="lab_sm_SupplementalCashFlowInformationOperatingActivitiesAbstract_71ac508d-f6f6-4c65-935f-be93924556a5_terseLabel_en-US" xlink:label="lab_sm_SupplementalCashFlowInformationOperatingActivitiesAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Supplemental Cash Flow Information - Operating activities:</link:label>
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    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsGainLossLineItems" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeInstrumentsGainLossLineItems"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossLineItems" xlink:to="lab_us-gaap_DerivativeInstrumentsGainLossLineItems" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_EntityInteractiveDataCurrent_f73ec416-2818-44c9-b712-c3880c49fbea_terseLabel_en-US" xlink:label="lab_dei_EntityInteractiveDataCurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Entity Interactive Data Current</link:label>
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    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityInteractiveDataCurrent" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_EntityInteractiveDataCurrent"/>
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    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityIncorporationStateCountryCode" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_EntityIncorporationStateCountryCode"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_EntityIncorporationStateCountryCode" xlink:to="lab_dei_EntityIncorporationStateCountryCode" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AccountsReceivableNetCurrent_711c1928-7293-493f-950e-302b7b414226_terseLabel_en-US" xlink:label="lab_us-gaap_AccountsReceivableNetCurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Accounts receivable</link:label>
    <link:label id="lab_us-gaap_AccountsReceivableNetCurrent_de776e03-f3c7-4c74-af3f-7d3872ce15ea_verboseLabel_en-US" xlink:label="lab_us-gaap_AccountsReceivableNetCurrent" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Accounts receivable from contracts with customers</link:label>
    <link:label id="lab_us-gaap_AccountsReceivableNetCurrent_label_en-US" xlink:label="lab_us-gaap_AccountsReceivableNetCurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Accounts Receivable, after Allowance for Credit Loss, Current</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsReceivableNetCurrent" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccountsReceivableNetCurrent"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AccountsReceivableNetCurrent" xlink:to="lab_us-gaap_AccountsReceivableNetCurrent" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue_01fabb8b-47c9-4845-a776-c39fae9f10e3_terseLabel_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Total lease payments</link:label>
    <link:label id="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue_label_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Lessee, Operating Lease, Liability, to be Paid</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue" xlink:to="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue" xlink:type="arc" order="1"/>
    <link:label id="lab_sm_NoncashInvestingAndFinancingActivitiesText_6d46b3dd-559c-4f4d-a684-e4df63b11257_terseLabel_en-US" xlink:label="lab_sm_NoncashInvestingAndFinancingActivitiesText" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Non-cash investing and financing activities (2)(3)</link:label>
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    <link:label id="lab_sm_NoncashInvestingAndFinancingActivitiesText_documentation_en-US" xlink:label="lab_sm_NoncashInvestingAndFinancingActivitiesText" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Noncash Investing and Financing Activities Text</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sm_NoncashInvestingAndFinancingActivitiesText" xlink:href="sm-20200930.xsd#sm_NoncashInvestingAndFinancingActivitiesText"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sm_NoncashInvestingAndFinancingActivitiesText" xlink:to="lab_sm_NoncashInvestingAndFinancingActivitiesText" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AdjustmentsToAdditionalPaidInCapitalOther_65752282-2f70-42e7-a1a2-a8663e755bda_terseLabel_en-US" xlink:label="lab_us-gaap_AdjustmentsToAdditionalPaidInCapitalOther" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Other</link:label>
    <link:label id="lab_us-gaap_AdjustmentsToAdditionalPaidInCapitalOther_label_en-US" xlink:label="lab_us-gaap_AdjustmentsToAdditionalPaidInCapitalOther" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Adjustments to Additional Paid in Capital, Other</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalOther" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalOther"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalOther" xlink:to="lab_us-gaap_AdjustmentsToAdditionalPaidInCapitalOther" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RestrictedCashNoncurrent_a59dd38f-0a87-4897-94ff-bb60654db269_terseLabel_en-US" xlink:label="lab_us-gaap_RestrictedCashNoncurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Restricted cash (1)</link:label>
    <link:label id="lab_us-gaap_RestrictedCashNoncurrent_label_en-US" xlink:label="lab_us-gaap_RestrictedCashNoncurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Restricted Cash, Noncurrent</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedCashNoncurrent" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RestrictedCashNoncurrent"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RestrictedCashNoncurrent" xlink:to="lab_us-gaap_RestrictedCashNoncurrent" xlink:type="arc" order="1"/>
    <link:label id="lab_sm_WellsInProgress_26ba8c25-8304-4d9f-82dd-ed6c27d7145a_terseLabel_en-US" xlink:label="lab_sm_WellsInProgress" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Wells in progress</link:label>
    <link:label id="lab_sm_WellsInProgress_label_en-US" xlink:label="lab_sm_WellsInProgress" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Wells in Progress</link:label>
    <link:label id="lab_sm_WellsInProgress_documentation_en-US" xlink:label="lab_sm_WellsInProgress" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Oil and gas properties under development using the successful efforts method that are not being amortized</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sm_WellsInProgress" xlink:href="sm-20200930.xsd#sm_WellsInProgress"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sm_WellsInProgress" xlink:to="lab_sm_WellsInProgress" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LesseeOperatingLeaseRemainingLeaseTerm_39a30aa3-f239-49bc-aa63-de24885bcf07_terseLabel_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeaseRemainingLeaseTerm" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Lessee, Operating Lease, Remaining Lease Term</link:label>
    <link:label id="lab_us-gaap_LesseeOperatingLeaseRemainingLeaseTerm_label_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeaseRemainingLeaseTerm" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Lessee, Operating Lease, Remaining Lease Term</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseRemainingLeaseTerm" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LesseeOperatingLeaseRemainingLeaseTerm"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LesseeOperatingLeaseRemainingLeaseTerm" xlink:to="lab_us-gaap_LesseeOperatingLeaseRemainingLeaseTerm" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensationGross_c52906aa-42f1-4f92-8a10-6c5985afe913_terseLabel_en-US" xlink:label="lab_us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensationGross" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Shares issued to directors</link:label>
    <link:label id="lab_us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensationGross_label_en-US" xlink:label="lab_us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensationGross" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Shares Issued, Shares, Share-based Payment Arrangement, before Forfeiture</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensationGross" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensationGross"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensationGross" xlink:to="lab_us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensationGross" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_EntityAddressPostalZipCode_f554b784-27ac-443c-abef-6e11a371818f_terseLabel_en-US" xlink:label="lab_dei_EntityAddressPostalZipCode" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Entity Address, Postal Zip Code</link:label>
    <link:label id="lab_dei_EntityAddressPostalZipCode_label_en-US" xlink:label="lab_dei_EntityAddressPostalZipCode" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Entity Address, Postal Zip Code</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressPostalZipCode" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_EntityAddressPostalZipCode"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_EntityAddressPostalZipCode" xlink:to="lab_dei_EntityAddressPostalZipCode" xlink:type="arc" order="1"/>
    <link:label id="lab_sm_ImpairmentofUnprovedOilandGasProperties_438e88be-893d-4c4a-a7c8-bfeb19719ab7_terseLabel_en-US" xlink:label="lab_sm_ImpairmentofUnprovedOilandGasProperties" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Abandonment and impairment of unproved properties</link:label>
    <link:label id="lab_sm_ImpairmentofUnprovedOilandGasProperties_label_en-US" xlink:label="lab_sm_ImpairmentofUnprovedOilandGasProperties" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Impairment of Unproved Oil and Gas Properties</link:label>
    <link:label id="lab_sm_ImpairmentofUnprovedOilandGasProperties_documentation_en-US" xlink:label="lab_sm_ImpairmentofUnprovedOilandGasProperties" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Accumulated expirations or loss on unproved oil and gas properties.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sm_ImpairmentofUnprovedOilandGasProperties" xlink:href="sm-20200930.xsd#sm_ImpairmentofUnprovedOilandGasProperties"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sm_ImpairmentofUnprovedOilandGasProperties" xlink:to="lab_sm_ImpairmentofUnprovedOilandGasProperties" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ExtinguishmentOfDebtTypeDomain_4545eb2d-a7d1-455d-a28e-39d2a41104be_terseLabel_en-US" xlink:label="lab_us-gaap_ExtinguishmentOfDebtTypeDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Extinguishment of Debt, Type [Domain]</link:label>
    <link:label id="lab_us-gaap_ExtinguishmentOfDebtTypeDomain_label_en-US" xlink:label="lab_us-gaap_ExtinguishmentOfDebtTypeDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Extinguishment of Debt, Type [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ExtinguishmentOfDebtTypeDomain" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ExtinguishmentOfDebtTypeDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ExtinguishmentOfDebtTypeDomain" xlink:to="lab_us-gaap_ExtinguishmentOfDebtTypeDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardPurchasePriceOfCommonStockPercent_7a9fc369-8363-4038-8d53-fd72f770a10b_terseLabel_en-US" xlink:label="lab_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardPurchasePriceOfCommonStockPercent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Purchase Price of Common Stock, Percent</link:label>
    <link:label id="lab_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardPurchasePriceOfCommonStockPercent_label_en-US" xlink:label="lab_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardPurchasePriceOfCommonStockPercent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Purchase Price of Common Stock, Percent</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardPurchasePriceOfCommonStockPercent" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardPurchasePriceOfCommonStockPercent"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardPurchasePriceOfCommonStockPercent" xlink:to="lab_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardPurchasePriceOfCommonStockPercent" xlink:type="arc" order="1"/>
    <link:label id="lab_sm_ScheduleOfLongTermDebtInstrumentsSeniorNotesTenderedTableTextBlock_e3ae7861-f296-402d-8865-02053c5a7b65_terseLabel_en-US" xlink:label="lab_sm_ScheduleOfLongTermDebtInstrumentsSeniorNotesTenderedTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule of Long-Term Debt Instruments, Old Notes Tendered [Table Text Block]</link:label>
    <link:label id="lab_sm_ScheduleOfLongTermDebtInstrumentsSeniorNotesTenderedTableTextBlock_label_en-US" xlink:label="lab_sm_ScheduleOfLongTermDebtInstrumentsSeniorNotesTenderedTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule of Long-Term Debt Instruments, Senior Notes Tendered [Table Text Block]</link:label>
    <link:label id="lab_sm_ScheduleOfLongTermDebtInstrumentsSeniorNotesTenderedTableTextBlock_documentation_en-US" xlink:label="lab_sm_ScheduleOfLongTermDebtInstrumentsSeniorNotesTenderedTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule of Long-Term Debt Instruments, Senior Notes Tendered [Table Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sm_ScheduleOfLongTermDebtInstrumentsSeniorNotesTenderedTableTextBlock" xlink:href="sm-20200930.xsd#sm_ScheduleOfLongTermDebtInstrumentsSeniorNotesTenderedTableTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sm_ScheduleOfLongTermDebtInstrumentsSeniorNotesTenderedTableTextBlock" xlink:to="lab_sm_ScheduleOfLongTermDebtInstrumentsSeniorNotesTenderedTableTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_DocumentTransitionReport_4872f011-11b1-4954-ad1c-47086b182be9_terseLabel_en-US" xlink:label="lab_dei_DocumentTransitionReport" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Document Transition Report</link:label>
    <link:label id="lab_dei_DocumentTransitionReport_label_en-US" xlink:label="lab_dei_DocumentTransitionReport" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Document Transition Report</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentTransitionReport" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_DocumentTransitionReport"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_DocumentTransitionReport" xlink:to="lab_dei_DocumentTransitionReport" xlink:type="arc" order="1"/>
    <link:label id="lab_sm_EarlyTerminationPenaltyforRigContractCancellation_59871fe5-0fcd-45b3-b90b-a53c5d406c89_terseLabel_en-US" xlink:label="lab_sm_EarlyTerminationPenaltyforRigContractCancellation" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Early Termination Penalty for Rig Contract Cancellation</link:label>
    <link:label id="lab_sm_EarlyTerminationPenaltyforRigContractCancellation_label_en-US" xlink:label="lab_sm_EarlyTerminationPenaltyforRigContractCancellation" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Early Termination Penalty for Rig Contract Cancellation</link:label>
    <link:label id="lab_sm_EarlyTerminationPenaltyforRigContractCancellation_documentation_en-US" xlink:label="lab_sm_EarlyTerminationPenaltyforRigContractCancellation" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Early Termination Penalty for Rig Contract Cancellation</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sm_EarlyTerminationPenaltyforRigContractCancellation" xlink:href="sm-20200930.xsd#sm_EarlyTerminationPenaltyforRigContractCancellation"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sm_EarlyTerminationPenaltyforRigContractCancellation" xlink:to="lab_sm_EarlyTerminationPenaltyforRigContractCancellation" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ImpairmentOfOilAndGasProperties_6d52e2a7-1554-4b82-ba0c-851fab9ae661_verboseLabel_en-US" xlink:label="lab_us-gaap_ImpairmentOfOilAndGasProperties" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Impairment</link:label>
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    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligation" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RevenueRemainingPerformanceObligation"/>
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    <link:label id="lab_us-gaap_AllocatedShareBasedCompensationExpense_4751234e-2411-44db-a156-de14ba3dd9f3_terseLabel_en-US" xlink:label="lab_us-gaap_AllocatedShareBasedCompensationExpense" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Stock-based compensation expense</link:label>
    <link:label id="lab_us-gaap_AllocatedShareBasedCompensationExpense_label_en-US" xlink:label="lab_us-gaap_AllocatedShareBasedCompensationExpense" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Share-based Payment Arrangement, Expense</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllocatedShareBasedCompensationExpense" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AllocatedShareBasedCompensationExpense"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AllocatedShareBasedCompensationExpense" xlink:to="lab_us-gaap_AllocatedShareBasedCompensationExpense" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_StockIssuedDuringPeriodValueEmployeeStockPurchasePlan_e7385907-1cd3-4357-8d9b-6b21781ff9f6_terseLabel_en-US" xlink:label="lab_us-gaap_StockIssuedDuringPeriodValueEmployeeStockPurchasePlan" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Issuance of common stock under Employee Stock Purchase Plan (Amount)</link:label>
    <link:label id="lab_us-gaap_StockIssuedDuringPeriodValueEmployeeStockPurchasePlan_label_en-US" xlink:label="lab_us-gaap_StockIssuedDuringPeriodValueEmployeeStockPurchasePlan" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Stock Issued During Period, Value, Employee Stock Purchase Plan</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueEmployeeStockPurchasePlan" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueEmployeeStockPurchasePlan"/>
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    <link:label id="lab_us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax_120a707f-81f1-4cb0-92cc-5e271e5dd60a_verboseLabel_en-US" xlink:label="lab_us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Oil, gas, and NGL production revenue</link:label>
    <link:label id="lab_us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax_863e9dcc-c4be-4580-9483-dc9e7b5fef7c_terseLabel_en-US" xlink:label="lab_us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Revenue from Contract with Customer, Including Assessed Tax</link:label>
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    <link:label id="lab_us-gaap_CommonStockValue_d72ec3c0-6528-4c94-8820-94865256287f_terseLabel_en-US" xlink:label="lab_us-gaap_CommonStockValue" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Common stock, $0.01 par value - authorized: 200,000,000 shares; issued and outstanding: 114,572,800 and 112,987,952 shares, respectively</link:label>
    <link:label id="lab_us-gaap_CommonStockValue_label_en-US" xlink:label="lab_us-gaap_CommonStockValue" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Common Stock, Value, Issued</link:label>
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    <link:label id="lab_dei_DocumentFiscalYearFocus_ef41c8ab-fd51-453b-86d2-ed7efbb532ca_terseLabel_en-US" xlink:label="lab_dei_DocumentFiscalYearFocus" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Document Fiscal Year Focus</link:label>
    <link:label id="lab_dei_DocumentFiscalYearFocus_label_en-US" xlink:label="lab_dei_DocumentFiscalYearFocus" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Document Fiscal Year Focus</link:label>
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    <link:label id="lab_sm_AcquisitionsDivestituresandAssetsHeldforSaleTextBlock_8faff735-3167-41b4-a292-358938f68893_terseLabel_en-US" xlink:label="lab_sm_AcquisitionsDivestituresandAssetsHeldforSaleTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Divestitures, Assets Held for Sale, and Acquisitions</link:label>
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    <link:label id="lab_sm_AcquisitionsDivestituresandAssetsHeldforSaleTextBlock_documentation_en-US" xlink:label="lab_sm_AcquisitionsDivestituresandAssetsHeldforSaleTextBlock" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">The entire disclosure of activity related to acquisitions, divestitures, and assets held for sale. [Text Block]</link:label>
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    <link:label id="lab_us-gaap_AssetsNoncurrentAbstract_4eaf0b26-3c23-4d68-9969-d7fc4d39b153_terseLabel_en-US" xlink:label="lab_us-gaap_AssetsNoncurrentAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Noncurrent assets:</link:label>
    <link:label id="lab_us-gaap_AssetsNoncurrentAbstract_label_en-US" xlink:label="lab_us-gaap_AssetsNoncurrentAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Assets, Noncurrent [Abstract]</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AssetsNoncurrentAbstract" xlink:to="lab_us-gaap_AssetsNoncurrentAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_EntityCurrentReportingStatus_c24622d9-d6c5-44f0-a3a2-bbd300bd1467_terseLabel_en-US" xlink:label="lab_dei_EntityCurrentReportingStatus" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Entity Current Reporting Status</link:label>
    <link:label id="lab_dei_EntityCurrentReportingStatus_label_en-US" xlink:label="lab_dei_EntityCurrentReportingStatus" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Entity Current Reporting Status</link:label>
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    <link:label id="lab_sm_DebtInstrumentRepurchaseDiscount_b29f7017-e0fb-41aa-a938-0340e3343516_terseLabel_en-US" xlink:label="lab_sm_DebtInstrumentRepurchaseDiscount" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Discount realized on extinguishment of debt</link:label>
    <link:label id="lab_sm_DebtInstrumentRepurchaseDiscount_label_en-US" xlink:label="lab_sm_DebtInstrumentRepurchaseDiscount" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Debt Instrument, Repurchase Discount</link:label>
    <link:label id="lab_sm_DebtInstrumentRepurchaseDiscount_documentation_en-US" xlink:label="lab_sm_DebtInstrumentRepurchaseDiscount" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Discount realized on debt instrument that was repurchased.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sm_DebtInstrumentRepurchaseDiscount" xlink:href="sm-20200930.xsd#sm_DebtInstrumentRepurchaseDiscount"/>
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    <link:label id="lab_us-gaap_ReceivableTypeDomain_4d288991-69b1-4d7d-87ae-438259c958ea_terseLabel_en-US" xlink:label="lab_us-gaap_ReceivableTypeDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Receivable Type [Domain]</link:label>
    <link:label id="lab_us-gaap_ReceivableTypeDomain_label_en-US" xlink:label="lab_us-gaap_ReceivableTypeDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Receivable [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReceivableTypeDomain" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ReceivableTypeDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ReceivableTypeDomain" xlink:to="lab_us-gaap_ReceivableTypeDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DerivativeFloorPrice_d78de118-4bc6-41f8-87b1-597ce1b1abd8_terseLabel_en-US" xlink:label="lab_us-gaap_DerivativeFloorPrice" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Derivative, Weighted-Average Floor Price</link:label>
    <link:label id="lab_us-gaap_DerivativeFloorPrice_label_en-US" xlink:label="lab_us-gaap_DerivativeFloorPrice" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Derivative, Floor Price</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeFloorPrice" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeFloorPrice"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DerivativeFloorPrice" xlink:to="lab_us-gaap_DerivativeFloorPrice" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation_802001d7-73b0-4fa8-899e-09b5bd6e61c0_terseLabel_en-US" xlink:label="lab_us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Stock-based compensation expense (Shares)</link:label>
    <link:label id="lab_us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation_label_en-US" xlink:label="lab_us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Shares Issued, Shares, Share-based Payment Arrangement, after Forfeiture</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation" xlink:to="lab_us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DebtInstrumentTable_7f140200-d069-4bc2-8441-73023a5c5414_verboseLabel_en-US" xlink:label="lab_us-gaap_DebtInstrumentTable" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule of Long-Term Debt [Table]</link:label>
    <link:label id="lab_us-gaap_DebtInstrumentTable_0b632d9b-c564-455e-a056-9c346abbe18d_terseLabel_en-US" xlink:label="lab_us-gaap_DebtInstrumentTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule of Senior Notes [Table]</link:label>
    <link:label id="lab_us-gaap_DebtInstrumentTable_label_en-US" xlink:label="lab_us-gaap_DebtInstrumentTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule of Long-term Debt Instruments [Table]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentTable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DebtInstrumentTable" xlink:to="lab_us-gaap_DebtInstrumentTable" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_74583966-08d4-42c6-a274-ddffd6b6cfd6_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value</link:label>
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    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:to="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:type="arc" order="1"/>
    <link:label id="lab_sm_BorrowingBaseUtilizationOf50PercentOrMoreButLessThan75PercentMember_dd5da9f1-957d-434d-901e-9d85976b3c68_terseLabel_en-US" xlink:label="lab_sm_BorrowingBaseUtilizationOf50PercentOrMoreButLessThan75PercentMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Borrowing Base Utilization Of 50 Percent Or More But Less Than 75 Percent [Member]</link:label>
    <link:label id="lab_sm_BorrowingBaseUtilizationOf50PercentOrMoreButLessThan75PercentMember_label_en-US" xlink:label="lab_sm_BorrowingBaseUtilizationOf50PercentOrMoreButLessThan75PercentMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Borrowing Base Utilization Of 50 Percent Or More But Less Than 75 Percent [Member]</link:label>
    <link:label id="lab_sm_BorrowingBaseUtilizationOf50PercentOrMoreButLessThan75PercentMember_documentation_en-US" xlink:label="lab_sm_BorrowingBaseUtilizationOf50PercentOrMoreButLessThan75PercentMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">The borrowing base of 50 percent or more, but less than 75 percent utilized by the entity.</link:label>
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    <link:label id="lab_us-gaap_CommonStockSharesIssued_3b197de8-7b1b-4130-9e4c-7c0b5874e8c3_terseLabel_en-US" xlink:label="lab_us-gaap_CommonStockSharesIssued" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Common Stock, Shares, Issued</link:label>
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    <link:label id="lab_us-gaap_EurodollarMember_1abb3d03-5a39-4d22-b911-dc8cc2666456_terseLabel_en-US" xlink:label="lab_us-gaap_EurodollarMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Eurodollar [Member]</link:label>
    <link:label id="lab_us-gaap_EurodollarMember_label_en-US" xlink:label="lab_us-gaap_EurodollarMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Eurodollar [Member]</link:label>
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    <link:label id="lab_sm_IncreaseToPermittedSecondLienDebt_a7e38e5d-b69f-45c9-b57f-9d3253bf1a4f_terseLabel_en-US" xlink:label="lab_sm_IncreaseToPermittedSecondLienDebt" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Increase to Permitted Second Lien Debt</link:label>
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    <link:label id="lab_sm_IncreaseToPermittedSecondLienDebt_documentation_en-US" xlink:label="lab_sm_IncreaseToPermittedSecondLienDebt" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Increase to Permitted Second Lien Debt</link:label>
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    <link:label id="lab_us-gaap_OperatingLeaseLiability_e2bf3247-2477-4a31-aa4a-30bd32dad0c6_terseLabel_en-US" xlink:label="lab_us-gaap_OperatingLeaseLiability" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Total operating lease liability</link:label>
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    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLiability" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OperatingLeaseLiability"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OperatingLeaseLiability" xlink:to="lab_us-gaap_OperatingLeaseLiability" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LongTermDebtNoncurrent_c45f1c6e-4006-4161-b73c-390f7f4257e0_terseLabel_en-US" xlink:label="lab_us-gaap_LongTermDebtNoncurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Senior Notes, net</link:label>
    <link:label id="lab_us-gaap_LongTermDebtNoncurrent_label_en-US" xlink:label="lab_us-gaap_LongTermDebtNoncurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Long-term Debt, Excluding Current Maturities</link:label>
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    <link:label id="lab_sm_WTIMidlandNYMEXWTIMember_de194711-c943-4a52-b3b9-878a6a2f7893_terseLabel_en-US" xlink:label="lab_sm_WTIMidlandNYMEXWTIMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">WTI Midland NYMEX WTI [Member]</link:label>
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    <link:label id="lab_sm_WTIMidlandNYMEXWTIMember_documentation_en-US" xlink:label="lab_sm_WTIMidlandNYMEXWTIMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">WTI Midland NYMEX WTI [Member]</link:label>
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    <link:label id="lab_sm_ShareBasedCompensationArrangementByShareBasedPaymentAwardMaximumEmployeeSubscription_4a9b43a3-9025-413c-9180-f4b132e662a6_terseLabel_en-US" xlink:label="lab_sm_ShareBasedCompensationArrangementByShareBasedPaymentAwardMaximumEmployeeSubscription" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Maximum Employee Subscription</link:label>
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    <link:label id="lab_us-gaap_DebtInstrumentLineItems_e65f5f4d-8131-4952-8a3e-3ec9ed4e1250_verboseLabel_en-US" xlink:label="lab_us-gaap_DebtInstrumentLineItems" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Long-Term Debt [Line Items]</link:label>
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    <link:label id="lab_us-gaap_DebtInstrumentLineItems_label_en-US" xlink:label="lab_us-gaap_DebtInstrumentLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Debt Instrument [Line Items]</link:label>
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    <link:label id="lab_us-gaap_StatementOfIncomeAndComprehensiveIncomeAbstract_5259377c-93a2-432e-bdcc-ebcab9682a75_terseLabel_en-US" xlink:label="lab_us-gaap_StatementOfIncomeAndComprehensiveIncomeAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Statement of Comprehensive Income [Abstract]</link:label>
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    <link:label id="lab_us-gaap_StockholdersEquity_cc60742e-3085-46ac-9bb8-fd91d2ade7d7_totalLabel_en-US" xlink:label="lab_us-gaap_StockholdersEquity" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Total stockholders&#8217; equity</link:label>
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    <link:label id="lab_us-gaap_ConcentrationRiskTypeDomain_7077b1b0-f494-4ff2-8013-bb42ebf97fb9_terseLabel_en-US" xlink:label="lab_us-gaap_ConcentrationRiskTypeDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Concentration Type [Domain]</link:label>
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    <link:label id="lab_sm_NYMEXOilCollarContractsMember_93c4b2b3-e84b-4a26-ab27-41bea0dd3f7e_terseLabel_en-US" xlink:label="lab_sm_NYMEXOilCollarContractsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">NYMEX Oil Collar Contracts [Member]</link:label>
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    <link:loc xlink:type="locator" xlink:label="loc_sm_NYMEXOilCollarContractsMember" xlink:href="sm-20200930.xsd#sm_NYMEXOilCollarContractsMember"/>
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    <link:label id="lab_us-gaap_LiabilitiesNoncurrent_a393f9c7-8e39-4bd7-96ac-7404eb930b28_totalLabel_en-US" xlink:label="lab_us-gaap_LiabilitiesNoncurrent" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Total noncurrent liabilities</link:label>
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    <link:label id="lab_dei_EntityAddressCityOrTown_c28aa459-96e5-4b51-aeb7-9077dc8ce1d8_terseLabel_en-US" xlink:label="lab_dei_EntityAddressCityOrTown" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Entity Address, City or Town</link:label>
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    <link:label id="lab_sm_A100SeniorSecuredNotesDue2025Member_label_en-US" xlink:label="lab_sm_A100SeniorSecuredNotesDue2025Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">10.0% Senior Secured Notes due 2025 [Member]</link:label>
    <link:label id="lab_sm_A100SeniorSecuredNotesDue2025Member_documentation_en-US" xlink:label="lab_sm_A100SeniorSecuredNotesDue2025Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">10.0% Senior Secured Notes due 2025 [Member]</link:label>
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    <link:label id="lab_sm_LetterofCreditDividendRestrictionsAmount_7db572fe-1ecc-4ce1-93be-96f29a51d5ae_terseLabel_en-US" xlink:label="lab_sm_LetterofCreditDividendRestrictionsAmount" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Revolving credit facility, dividend restrictions, amount</link:label>
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    <link:label id="lab_sm_LetterofCreditDividendRestrictionsAmount_documentation_en-US" xlink:label="lab_sm_LetterofCreditDividendRestrictionsAmount" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Letter of Credit, Dividend Restrictions, Amount</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sm_LetterofCreditDividendRestrictionsAmount" xlink:href="sm-20200930.xsd#sm_LetterofCreditDividendRestrictionsAmount"/>
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    <link:label id="lab_us-gaap_DebtInstrumentFairValueDisclosureAbstract_fc51989c-c1ce-4a54-8a03-ac5497eca816_terseLabel_en-US" xlink:label="lab_us-gaap_DebtInstrumentFairValueDisclosureAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Debt Instrument, Fair Value Disclosure [Abstract]</link:label>
    <link:label id="lab_us-gaap_DebtInstrumentFairValueDisclosureAbstract_label_en-US" xlink:label="lab_us-gaap_DebtInstrumentFairValueDisclosureAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Debt Instrument, Fair Value Disclosure [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentFairValueDisclosureAbstract" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentFairValueDisclosureAbstract"/>
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    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
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    <link:label id="lab_us-gaap_RestrictedStockUnitsRSUMember_841ace85-3a6c-4ee0-9f7b-b323c0f4abd8_terseLabel_en-US" xlink:label="lab_us-gaap_RestrictedStockUnitsRSUMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Restricted Stock Units (RSUs)</link:label>
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    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockUnitsRSUMember" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RestrictedStockUnitsRSUMember"/>
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    <link:label id="lab_sm_IncomeTaxesRefundAlternativeMinimumTaxCARESAct_2e997291-fed7-4b87-b1bd-b58e6e9ce4e9_terseLabel_en-US" xlink:label="lab_sm_IncomeTaxesRefundAlternativeMinimumTaxCARESAct" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Proceeds from income tax refunds</link:label>
    <link:label id="lab_sm_IncomeTaxesRefundAlternativeMinimumTaxCARESAct_label_en-US" xlink:label="lab_sm_IncomeTaxesRefundAlternativeMinimumTaxCARESAct" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Income Taxes Refund, Alternative Minimum Tax, CARES Act</link:label>
    <link:label id="lab_sm_IncomeTaxesRefundAlternativeMinimumTaxCARESAct_documentation_en-US" xlink:label="lab_sm_IncomeTaxesRefundAlternativeMinimumTaxCARESAct" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Income Taxes Refund, Alternative Minimum Tax, CARES Act</link:label>
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    <link:label id="lab_us-gaap_OperatingLeaseCost_de7d593b-f78b-478a-8131-ae54317a49f7_terseLabel_en-US" xlink:label="lab_us-gaap_OperatingLeaseCost" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Operating lease cost</link:label>
    <link:label id="lab_us-gaap_OperatingLeaseCost_label_en-US" xlink:label="lab_us-gaap_OperatingLeaseCost" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Operating Lease, Cost</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseCost" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OperatingLeaseCost"/>
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    <link:label id="lab_us-gaap_AccountsPayableAndAccruedLiabilitiesCurrent_26938048-6ccd-4b67-9a88-faa69acfd9cc_terseLabel_en-US" xlink:label="lab_us-gaap_AccountsPayableAndAccruedLiabilitiesCurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Accounts payable and accrued expenses</link:label>
    <link:label id="lab_us-gaap_AccountsPayableAndAccruedLiabilitiesCurrent_label_en-US" xlink:label="lab_us-gaap_AccountsPayableAndAccruedLiabilitiesCurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Accounts Payable and Accrued Liabilities, Current</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsPayableAndAccruedLiabilitiesCurrent" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccountsPayableAndAccruedLiabilitiesCurrent"/>
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    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardMaximumEmployeeSubscriptionRate_dee680dd-0b05-435c-9ca1-96b954045b62_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardMaximumEmployeeSubscriptionRate" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Maximum Employee Subscription Rate</link:label>
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    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardMaximumEmployeeSubscriptionRate" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardMaximumEmployeeSubscriptionRate"/>
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    <link:label id="lab_us-gaap_GeneralAndAdministrativeExpense_0885d4d1-df0f-478f-bfca-7c632556a1e3_terseLabel_en-US" xlink:label="lab_us-gaap_GeneralAndAdministrativeExpense" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">General and administrative</link:label>
    <link:label id="lab_us-gaap_GeneralAndAdministrativeExpense_label_en-US" xlink:label="lab_us-gaap_GeneralAndAdministrativeExpense" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">General and Administrative Expense</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GeneralAndAdministrativeExpense" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_GeneralAndAdministrativeExpense"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_GeneralAndAdministrativeExpense" xlink:to="lab_us-gaap_GeneralAndAdministrativeExpense" xlink:type="arc" order="1"/>
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    <link:label id="lab_us-gaap_LineOfCreditFacilityLineItems_184a7a06-7757-4d8c-b070-c8616878ad5b_terseLabel_en-US" xlink:label="lab_us-gaap_LineOfCreditFacilityLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Line of Credit Facility [Line Items]</link:label>
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    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityLineItems" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LineOfCreditFacilityLineItems"/>
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    <link:label id="lab_us-gaap_OtherNoncashIncomeExpense_163c9061-251e-49ef-bd5d-c848429ee110_negatedLabel_en-US" xlink:label="lab_us-gaap_OtherNoncashIncomeExpense" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Other, net</link:label>
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    <link:label id="lab_us-gaap_PropertyPlantAndEquipmentNet_c3ea66f7-81c3-4798-99d9-06a62f3f0641_totalLabel_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentNet" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Total property and equipment, net</link:label>
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    <link:label id="lab_us-gaap_LesseeLeaseDescriptionTable_802e4284-4757-4fbc-bcb4-6983cfb1a600_terseLabel_en-US" xlink:label="lab_us-gaap_LesseeLeaseDescriptionTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Lessee, Lease, Description [Table]</link:label>
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    <link:label id="lab_us-gaap_OtherLiabilitiesCurrent_0a507fda-b887-451c-afd3-4ea2a1831c31_terseLabel_en-US" xlink:label="lab_us-gaap_OtherLiabilitiesCurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Other current liabilities</link:label>
    <link:label id="lab_us-gaap_OtherLiabilitiesCurrent_label_en-US" xlink:label="lab_us-gaap_OtherLiabilitiesCurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Other Liabilities, Current</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherLiabilitiesCurrent" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherLiabilitiesCurrent"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherLiabilitiesCurrent" xlink:to="lab_us-gaap_OtherLiabilitiesCurrent" xlink:type="arc" order="1"/>
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    <link:label id="lab_sm_GainsLossesonExtinguishmentofDebtNonCashPortion_label_en-US" xlink:label="lab_sm_GainsLossesonExtinguishmentofDebtNonCashPortion" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Gains (Losses) on Extinguishment of Debt, Non Cash Portion</link:label>
    <link:label id="lab_sm_GainsLossesonExtinguishmentofDebtNonCashPortion_documentation_en-US" xlink:label="lab_sm_GainsLossesonExtinguishmentofDebtNonCashPortion" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">The non cash portion of gains (losses) recorded on the extinguishment of debt related to the acceleration of deferred financing costs.</link:label>
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    <link:label id="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsRemainderOfFiscalYear_28643476-457a-4f12-bd5a-06b448a85d2a_terseLabel_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsRemainderOfFiscalYear" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Operating lease liability payments, due 2020 (remaining after September 30, 2020)</link:label>
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    <link:label id="lab_us-gaap_OtherComprehensiveIncomeLossNetOfTax_0807f747-15f1-4f80-a26c-c4b27ee45e0e_totalLabel_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeLossNetOfTax" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Total other comprehensive income, net of tax</link:label>
    <link:label id="lab_us-gaap_OtherComprehensiveIncomeLossNetOfTax_be36296c-f6f2-4d22-9800-5e7b893753cf_terseLabel_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeLossNetOfTax" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Other comprehensive income</link:label>
    <link:label id="lab_us-gaap_OtherComprehensiveIncomeLossNetOfTax_label_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeLossNetOfTax" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Other Comprehensive Income (Loss), Net of Tax</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTax"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax" xlink:to="lab_us-gaap_OtherComprehensiveIncomeLossNetOfTax" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LongtermDebtTypeAxis_f4484344-173f-45fc-a18f-cf64cc148b5e_terseLabel_en-US" xlink:label="lab_us-gaap_LongtermDebtTypeAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Long-term Debt, Type [Axis]</link:label>
    <link:label id="lab_us-gaap_LongtermDebtTypeAxis_label_en-US" xlink:label="lab_us-gaap_LongtermDebtTypeAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Long-term Debt, Type [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LongtermDebtTypeAxis" xlink:to="lab_us-gaap_LongtermDebtTypeAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AssetsCurrent_8e01e199-60ea-4793-a172-16415627eb8d_totalLabel_en-US" xlink:label="lab_us-gaap_AssetsCurrent" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Total current assets</link:label>
    <link:label id="lab_us-gaap_AssetsCurrent_label_en-US" xlink:label="lab_us-gaap_AssetsCurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Assets, Current</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsCurrent" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AssetsCurrent"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AssetsCurrent" xlink:to="lab_us-gaap_AssetsCurrent" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_CurrentFiscalYearEndDate_e236afe9-0bb0-454d-a075-44417d76307d_terseLabel_en-US" xlink:label="lab_dei_CurrentFiscalYearEndDate" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Current Fiscal Year End Date</link:label>
    <link:label id="lab_dei_CurrentFiscalYearEndDate_label_en-US" xlink:label="lab_dei_CurrentFiscalYearEndDate" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Current Fiscal Year End Date</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_CurrentFiscalYearEndDate" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_CurrentFiscalYearEndDate"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_CurrentFiscalYearEndDate" xlink:to="lab_dei_CurrentFiscalYearEndDate" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_OperatingExpensesAbstract_0cce4cdd-9bb0-4c95-853b-4508e3c59449_terseLabel_en-US" xlink:label="lab_us-gaap_OperatingExpensesAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Operating expenses:</link:label>
    <link:label id="lab_us-gaap_OperatingExpensesAbstract_label_en-US" xlink:label="lab_us-gaap_OperatingExpensesAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Operating Expenses [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingExpensesAbstract" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OperatingExpensesAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OperatingExpensesAbstract" xlink:to="lab_us-gaap_OperatingExpensesAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_sm_NYMEXOilSwapContractYear3Member_8b0cb983-6c56-4bab-97a0-00a39b2361fd_terseLabel_en-US" xlink:label="lab_sm_NYMEXOilSwapContractYear3Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">NYMEX Oil Swap Contract, 2022</link:label>
    <link:label id="lab_sm_NYMEXOilSwapContractYear3Member_label_en-US" xlink:label="lab_sm_NYMEXOilSwapContractYear3Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">NYMEX Oil Swap Contract, Year 3 [Member]</link:label>
    <link:label id="lab_sm_NYMEXOilSwapContractYear3Member_documentation_en-US" xlink:label="lab_sm_NYMEXOilSwapContractYear3Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">NYMEX Oil Swap Contract, Year 3 [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sm_NYMEXOilSwapContractYear3Member" xlink:href="sm-20200930.xsd#sm_NYMEXOilSwapContractYear3Member"/>
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    <link:label id="lab_us-gaap_EarningsPerShareAbstract_438232d6-3bd9-4a7a-9b82-a2b9dd36e39b_terseLabel_en-US" xlink:label="lab_us-gaap_EarningsPerShareAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Earnings Per Share [Abstract]</link:label>
    <link:label id="lab_us-gaap_EarningsPerShareAbstract_label_en-US" xlink:label="lab_us-gaap_EarningsPerShareAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Earnings Per Share [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareAbstract" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EarningsPerShareAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EarningsPerShareAbstract" xlink:to="lab_us-gaap_EarningsPerShareAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DisposalGroupIncludingDiscontinuedOperationPropertyPlantAndEquipment_efd3d1a4-7539-47d5-b424-90f6833e730d_terseLabel_en-US" xlink:label="lab_us-gaap_DisposalGroupIncludingDiscontinuedOperationPropertyPlantAndEquipment" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Properties held for sale, net</link:label>
    <link:label id="lab_us-gaap_DisposalGroupIncludingDiscontinuedOperationPropertyPlantAndEquipment_label_en-US" xlink:label="lab_us-gaap_DisposalGroupIncludingDiscontinuedOperationPropertyPlantAndEquipment" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Disposal Group, Including Discontinued Operation, Property, Plant and Equipment</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationPropertyPlantAndEquipment" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DisposalGroupIncludingDiscontinuedOperationPropertyPlantAndEquipment"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationPropertyPlantAndEquipment" xlink:to="lab_us-gaap_DisposalGroupIncludingDiscontinuedOperationPropertyPlantAndEquipment" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_CompensationRelatedCostsAbstract_label_en-US" xlink:label="lab_us-gaap_CompensationRelatedCostsAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Compensation Related Costs [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CompensationRelatedCostsAbstract" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CompensationRelatedCostsAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CompensationRelatedCostsAbstract" xlink:to="lab_us-gaap_CompensationRelatedCostsAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_sm_EmployeeStockPurchasePlanMember_0956fde4-d6f1-4651-8e0f-90a77306a04a_terseLabel_en-US" xlink:label="lab_sm_EmployeeStockPurchasePlanMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Employee Stock Purchase Plan [Member]</link:label>
    <link:label id="lab_sm_EmployeeStockPurchasePlanMember_label_en-US" xlink:label="lab_sm_EmployeeStockPurchasePlanMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Employee Stock Purchase Plan [Member]</link:label>
    <link:label id="lab_sm_EmployeeStockPurchasePlanMember_documentation_en-US" xlink:label="lab_sm_EmployeeStockPurchasePlanMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Employee Stock Purchase Plan</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sm_EmployeeStockPurchasePlanMember" xlink:href="sm-20200930.xsd#sm_EmployeeStockPurchasePlanMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sm_EmployeeStockPurchasePlanMember" xlink:to="lab_sm_EmployeeStockPurchasePlanMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights_7187d8f2-c80e-4e94-a1aa-6f0a2cc5fab4_terseLabel_en-US" xlink:label="lab_us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Class of Warrant or Right, Number of Securities Called by Warrants or Rights</link:label>
    <link:label id="lab_us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights_label_en-US" xlink:label="lab_us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Class of Warrant or Right, Number of Securities Called by Warrants or Rights</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights" xlink:to="lab_us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_NoncashOrPartNoncashAcquisitionNetNonmonetaryAssetsAcquiredLiabilitiesAssumed1_e1518c32-a706-4fa2-97cd-a3f2791950df_terseLabel_en-US" xlink:label="lab_us-gaap_NoncashOrPartNoncashAcquisitionNetNonmonetaryAssetsAcquiredLiabilitiesAssumed1" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Carrying value of properties exchanged</link:label>
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    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NoncashOrPartNoncashAcquisitionNetNonmonetaryAssetsAcquiredLiabilitiesAssumed1" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NoncashOrPartNoncashAcquisitionNetNonmonetaryAssetsAcquiredLiabilitiesAssumed1"/>
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    <link:label id="lab_dei_DocumentFiscalPeriodFocus_305f2d57-eafb-4073-ab6d-06b4fc06846c_terseLabel_en-US" xlink:label="lab_dei_DocumentFiscalPeriodFocus" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Document Fiscal Period Focus</link:label>
    <link:label id="lab_dei_DocumentFiscalPeriodFocus_label_en-US" xlink:label="lab_dei_DocumentFiscalPeriodFocus" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Document Fiscal Period Focus</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentFiscalPeriodFocus" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_DocumentFiscalPeriodFocus"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_DocumentFiscalPeriodFocus" xlink:to="lab_dei_DocumentFiscalPeriodFocus" xlink:type="arc" order="1"/>
    <link:label id="lab_sm_Derivativesettlementgainorloss_eec76c57-ea04-43d3-b468-f675a598d48b_terseLabel_en-US" xlink:label="lab_sm_Derivativesettlementgainorloss" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Derivative settlement gain or loss</link:label>
    <link:label id="lab_sm_Derivativesettlementgainorloss_label_en-US" xlink:label="lab_sm_Derivativesettlementgainorloss" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Derivative settlement gain or loss</link:label>
    <link:label id="lab_sm_Derivativesettlementgainorloss_documentation_en-US" xlink:label="lab_sm_Derivativesettlementgainorloss" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Realized gain or loss recognized in earnings from the settlement of derivative instruments not designated as hedges.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sm_Derivativesettlementgainorloss" xlink:href="sm-20200930.xsd#sm_Derivativesettlementgainorloss"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sm_Derivativesettlementgainorloss" xlink:to="lab_sm_Derivativesettlementgainorloss" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansAdjustmentNetOfTaxPortionAttributableToParent_b93f3646-1866-4fcc-a73f-f81529a29165_negatedLabel_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansAdjustmentNetOfTaxPortionAttributableToParent" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Pension liability adjustment</link:label>
    <link:label id="lab_us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansAdjustmentNetOfTaxPortionAttributableToParent_label_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansAdjustmentNetOfTaxPortionAttributableToParent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax and Reclassification Adjustment, Attributable to Parent</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansAdjustmentNetOfTaxPortionAttributableToParent" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansAdjustmentNetOfTaxPortionAttributableToParent"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansAdjustmentNetOfTaxPortionAttributableToParent" xlink:to="lab_us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansAdjustmentNetOfTaxPortionAttributableToParent" xlink:type="arc" order="1"/>
    <link:label id="lab_sm_ImpairmentofoilandgaspropertiesTableTextBlock_04d7db3d-16b9-40c2-9683-b84852b26fe3_terseLabel_en-US" xlink:label="lab_sm_ImpairmentofoilandgaspropertiesTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Impairment of oil and gas properties [Table Text Block]</link:label>
    <link:label id="lab_sm_ImpairmentofoilandgaspropertiesTableTextBlock_label_en-US" xlink:label="lab_sm_ImpairmentofoilandgaspropertiesTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Impairment of oil and gas properties [Table Text Block]</link:label>
    <link:label id="lab_sm_ImpairmentofoilandgaspropertiesTableTextBlock_documentation_en-US" xlink:label="lab_sm_ImpairmentofoilandgaspropertiesTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Impairment of oil and gas properties [Table Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sm_ImpairmentofoilandgaspropertiesTableTextBlock" xlink:href="sm-20200930.xsd#sm_ImpairmentofoilandgaspropertiesTableTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sm_ImpairmentofoilandgaspropertiesTableTextBlock" xlink:to="lab_sm_ImpairmentofoilandgaspropertiesTableTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DefinedBenefitPlanContributionsByEmployer_6d9f2b94-8bdf-40f8-a235-505a4a6751cc_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanContributionsByEmployer" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Employer contributions</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlanContributionsByEmployer_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanContributionsByEmployer" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Defined Benefit Plan, Plan Assets, Contributions by Employer</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanContributionsByEmployer" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DefinedBenefitPlanContributionsByEmployer"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanContributionsByEmployer" xlink:to="lab_us-gaap_DefinedBenefitPlanContributionsByEmployer" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_PropertyPlantAndEquipmentImpairment_6b45b33f-62be-40d3-a1d6-816590eefdc7_terseLabel_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentImpairment" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Property, Plant and Equipment, Impairment, Policy [Policy Text Block]</link:label>
    <link:label id="lab_us-gaap_PropertyPlantAndEquipmentImpairment_label_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentImpairment" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Property, Plant and Equipment, Impairment [Policy Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentImpairment" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PropertyPlantAndEquipmentImpairment"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentImpairment" xlink:to="lab_us-gaap_PropertyPlantAndEquipmentImpairment" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_SupplementalCashFlowInformationAbstract_8e95266b-7664-482b-9b94-2d9cae1bae7b_terseLabel_en-US" xlink:label="lab_us-gaap_SupplementalCashFlowInformationAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Supplemental schedule of additional cash flow information and non-cash activities:</link:label>
    <link:label id="lab_us-gaap_SupplementalCashFlowInformationAbstract_label_en-US" xlink:label="lab_us-gaap_SupplementalCashFlowInformationAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Supplemental Cash Flow Information [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SupplementalCashFlowInformationAbstract" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SupplementalCashFlowInformationAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SupplementalCashFlowInformationAbstract" xlink:to="lab_us-gaap_SupplementalCashFlowInformationAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_sm_ImpairmentofProvedOilandGasProperties_fad00131-8dd7-44ec-9735-c0fc44056fec_terseLabel_en-US" xlink:label="lab_sm_ImpairmentofProvedOilandGasProperties" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Impairment of proved oil and gas properties and related support equipment</link:label>
    <link:label id="lab_sm_ImpairmentofProvedOilandGasProperties_label_en-US" xlink:label="lab_sm_ImpairmentofProvedOilandGasProperties" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Impairment of Proved Oil and Gas Properties</link:label>
    <link:label id="lab_sm_ImpairmentofProvedOilandGasProperties_documentation_en-US" xlink:label="lab_sm_ImpairmentofProvedOilandGasProperties" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">The impairment expense recorded to reduce the value of proved oil and gas assets.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sm_ImpairmentofProvedOilandGasProperties" xlink:href="sm-20200930.xsd#sm_ImpairmentofProvedOilandGasProperties"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sm_ImpairmentofProvedOilandGasProperties" xlink:to="lab_sm_ImpairmentofProvedOilandGasProperties" xlink:type="arc" order="1"/>
    <link:label id="lab_sm_LineofCreditFacilityAggregateLenderCommitments_5fda8e20-fd8c-4370-b9ce-48e7be9aba76_totalLabel_en-US" xlink:label="lab_sm_LineofCreditFacilityAggregateLenderCommitments" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Revolving credit facility, aggregate lender commitments</link:label>
    <link:label id="lab_sm_LineofCreditFacilityAggregateLenderCommitments_label_en-US" xlink:label="lab_sm_LineofCreditFacilityAggregateLenderCommitments" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Line of Credit Facility, Aggregate Lender Commitments</link:label>
    <link:label id="lab_sm_LineofCreditFacilityAggregateLenderCommitments_documentation_en-US" xlink:label="lab_sm_LineofCreditFacilityAggregateLenderCommitments" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Line of Credit Facility, Aggregate Lender Commitments</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sm_LineofCreditFacilityAggregateLenderCommitments" xlink:href="sm-20200930.xsd#sm_LineofCreditFacilityAggregateLenderCommitments"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sm_LineofCreditFacilityAggregateLenderCommitments" xlink:to="lab_sm_LineofCreditFacilityAggregateLenderCommitments" xlink:type="arc" order="1"/>
    <link:label id="lab_sm_IndexPercentOfNaturalGasFixedSwaps_25ee28c5-87f5-4f22-8485-0d6a9239311e_terseLabel_en-US" xlink:label="lab_sm_IndexPercentOfNaturalGasFixedSwaps" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Index percent of natural gas fixed swaps</link:label>
    <link:label id="lab_sm_IndexPercentOfNaturalGasFixedSwaps_label_en-US" xlink:label="lab_sm_IndexPercentOfNaturalGasFixedSwaps" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Index percent of natural gas fixed swaps</link:label>
    <link:label id="lab_sm_IndexPercentOfNaturalGasFixedSwaps_documentation_en-US" xlink:label="lab_sm_IndexPercentOfNaturalGasFixedSwaps" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Index percent of natural gas fixed swaps</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sm_IndexPercentOfNaturalGasFixedSwaps" xlink:href="sm-20200930.xsd#sm_IndexPercentOfNaturalGasFixedSwaps"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sm_IndexPercentOfNaturalGasFixedSwaps" xlink:to="lab_sm_IndexPercentOfNaturalGasFixedSwaps" xlink:type="arc" order="1"/>
    <link:label id="lab_sm_NYMEXOilCalendarMonthAverageRollDifferentialContractsMember_c2b81259-b966-4422-ae9c-e169efce3833_terseLabel_en-US" xlink:label="lab_sm_NYMEXOilCalendarMonthAverageRollDifferentialContractsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">NYMEX Oil Calendar Month Average Roll Differential Contracts [Member]</link:label>
    <link:label id="lab_sm_NYMEXOilCalendarMonthAverageRollDifferentialContractsMember_label_en-US" xlink:label="lab_sm_NYMEXOilCalendarMonthAverageRollDifferentialContractsMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">NYMEX Oil Calendar Month Average Roll Differential Contracts [Member]</link:label>
    <link:label id="lab_sm_NYMEXOilCalendarMonthAverageRollDifferentialContractsMember_documentation_en-US" xlink:label="lab_sm_NYMEXOilCalendarMonthAverageRollDifferentialContractsMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">NYMEX Oil Calendar Month Average Roll Differential Contracts [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sm_NYMEXOilCalendarMonthAverageRollDifferentialContractsMember" xlink:href="sm-20200930.xsd#sm_NYMEXOilCalendarMonthAverageRollDifferentialContractsMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sm_NYMEXOilCalendarMonthAverageRollDifferentialContractsMember" xlink:to="lab_sm_NYMEXOilCalendarMonthAverageRollDifferentialContractsMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DebtInstrumentRedemptionPricePercentage_06c771c1-940d-4faa-b121-1d619efcdc91_terseLabel_en-US" xlink:label="lab_us-gaap_DebtInstrumentRedemptionPricePercentage" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Senior Unsecured Notes, Redemption Price, Percentage</link:label>
    <link:label id="lab_us-gaap_DebtInstrumentRedemptionPricePercentage_label_en-US" xlink:label="lab_us-gaap_DebtInstrumentRedemptionPricePercentage" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Debt Instrument, Redemption Price, Percentage</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentRedemptionPricePercentage" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentRedemptionPricePercentage"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DebtInstrumentRedemptionPricePercentage" xlink:to="lab_us-gaap_DebtInstrumentRedemptionPricePercentage" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans_3f3b7809-487b-43c9-a1f7-3b8603e30fcb_terseLabel_en-US" xlink:label="lab_us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Issuance of common stock under Employee Stock Purchase Plan (Shares)</link:label>
    <link:label id="lab_us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans_label_en-US" xlink:label="lab_us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Stock Issued During Period, Shares, Employee Stock Purchase Plans</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans" xlink:to="lab_us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_UnprovedOilAndGasPropertySuccessfulEffortMethod_c1b27eea-4685-4a48-bd0d-1082c0dba9a0_verboseLabel_en-US" xlink:label="lab_us-gaap_UnprovedOilAndGasPropertySuccessfulEffortMethod" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Unproved oil and gas properties</link:label>
    <link:label id="lab_us-gaap_UnprovedOilAndGasPropertySuccessfulEffortMethod_label_en-US" xlink:label="lab_us-gaap_UnprovedOilAndGasPropertySuccessfulEffortMethod" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Unproved Oil and Gas Property, Successful Effort Method</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnprovedOilAndGasPropertySuccessfulEffortMethod" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_UnprovedOilAndGasPropertySuccessfulEffortMethod"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_UnprovedOilAndGasPropertySuccessfulEffortMethod" xlink:to="lab_us-gaap_UnprovedOilAndGasPropertySuccessfulEffortMethod" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_EntityFilerCategory_ff70c0ec-e670-4440-b37a-e7cec108115c_terseLabel_en-US" xlink:label="lab_dei_EntityFilerCategory" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Entity Filer Category</link:label>
    <link:label id="lab_dei_EntityFilerCategory_label_en-US" xlink:label="lab_dei_EntityFilerCategory" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Entity Filer Category</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityFilerCategory" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_EntityFilerCategory"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_EntityFilerCategory" xlink:to="lab_dei_EntityFilerCategory" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_CommonStockMember_b4b6c83d-623d-4663-a2a7-8506a867ea3d_terseLabel_en-US" xlink:label="lab_us-gaap_CommonStockMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Common Stock</link:label>
    <link:label id="lab_us-gaap_CommonStockMember_label_en-US" xlink:label="lab_us-gaap_CommonStockMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Common Stock [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommonStockMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CommonStockMember" xlink:to="lab_us-gaap_CommonStockMember" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_ProductsAndServicesDomain_2c414410-a2b9-4a51-a50c-8eacbcc1b75d_terseLabel_en-US" xlink:label="lab_srt_ProductsAndServicesDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Product and Service [Domain]</link:label>
    <link:label id="lab_srt_ProductsAndServicesDomain_label_en-US" xlink:label="lab_srt_ProductsAndServicesDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Product and Service [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ProductsAndServicesDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_ProductsAndServicesDomain" xlink:to="lab_srt_ProductsAndServicesDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LesseeOperatingLeaseDiscountRate_8fab932d-3ae1-4f8d-9190-555094f6eb69_terseLabel_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeaseDiscountRate" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Weighted-average discount rate</link:label>
    <link:label id="lab_us-gaap_LesseeOperatingLeaseDiscountRate_label_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeaseDiscountRate" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Lessee, Operating Lease, Discount Rate</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseDiscountRate" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LesseeOperatingLeaseDiscountRate"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LesseeOperatingLeaseDiscountRate" xlink:to="lab_us-gaap_LesseeOperatingLeaseDiscountRate" xlink:type="arc" order="1"/>
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    <link:label id="lab_us-gaap_OilAndGasPropertyAbstract_aaee36c5-23ab-4008-b1a1-80c5078c3896_terseLabel_en-US" xlink:label="lab_us-gaap_OilAndGasPropertyAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Oil and Gas Property [Abstract]</link:label>
    <link:label id="lab_us-gaap_OilAndGasPropertyAbstract_label_en-US" xlink:label="lab_us-gaap_OilAndGasPropertyAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Oil and Gas Property [Abstract]</link:label>
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    <link:label id="lab_us-gaap_NoncashInvestingAndFinancingItemsAbstract_eb5d293b-2679-4e6a-8889-c1f9e86b675d_terseLabel_en-US" xlink:label="lab_us-gaap_NoncashInvestingAndFinancingItemsAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Non-cash investing and financing activities</link:label>
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    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable"/>
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    <link:label id="lab_us-gaap_LesseeOperatingLeaseLiabilityMaturityTableTextBlock_62957c7b-2d85-42a4-968c-0837a2526c91_terseLabel_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeaseLiabilityMaturityTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Operating lease liability maturities [Table Text Block]</link:label>
    <link:label id="lab_us-gaap_LesseeOperatingLeaseLiabilityMaturityTableTextBlock_label_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeaseLiabilityMaturityTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Lessee, Operating Lease, Liability, Maturity [Table Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityMaturityTableTextBlock" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityMaturityTableTextBlock"/>
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    <link:label id="lab_us-gaap_BasisOfAccountingPolicyPolicyTextBlock_cd7d160e-f9ad-42bc-823c-938dfeb3a0e1_terseLabel_en-US" xlink:label="lab_us-gaap_BasisOfAccountingPolicyPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Basis of Presentation, Policy [Policy Text Block]</link:label>
    <link:label id="lab_us-gaap_BasisOfAccountingPolicyPolicyTextBlock_label_en-US" xlink:label="lab_us-gaap_BasisOfAccountingPolicyPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Basis of Accounting, Policy [Policy Text Block]</link:label>
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    <link:label id="lab_sm_NYMEXOilSwapContractsMember_a7a2d6a8-a948-46e0-9aae-6432348cc2cd_terseLabel_en-US" xlink:label="lab_sm_NYMEXOilSwapContractsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">NYMEX Oil Swap Contracts [Member]</link:label>
    <link:label id="lab_sm_NYMEXOilSwapContractsMember_label_en-US" xlink:label="lab_sm_NYMEXOilSwapContractsMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">NYMEX Oil Swap Contracts [Member]</link:label>
    <link:label id="lab_sm_NYMEXOilSwapContractsMember_documentation_en-US" xlink:label="lab_sm_NYMEXOilSwapContractsMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">NYMEX Oil Swap Contracts [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sm_NYMEXOilSwapContractsMember" xlink:href="sm-20200930.xsd#sm_NYMEXOilSwapContractsMember"/>
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    <link:label id="lab_us-gaap_ProceedsFromSaleOfOilAndGasPropertyAndEquipment_ed704470-5311-459b-a2ac-e7f3e14662c1_verboseLabel_en-US" xlink:label="lab_us-gaap_ProceedsFromSaleOfOilAndGasPropertyAndEquipment" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Net proceeds from the sale of oil and gas properties (1)</link:label>
    <link:label id="lab_us-gaap_ProceedsFromSaleOfOilAndGasPropertyAndEquipment_label_en-US" xlink:label="lab_us-gaap_ProceedsFromSaleOfOilAndGasPropertyAndEquipment" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Proceeds from Sale of Oil and Gas Property and Equipment</link:label>
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    <link:label id="lab_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_595f08cd-def8-4c51-ab67-7b70ff0be61f_terseLabel_en-US" xlink:label="lab_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Basic weighted-average common shares outstanding</link:label>
    <link:label id="lab_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_735c1e48-9557-4238-9cf3-57083f1ac02e_verboseLabel_en-US" xlink:label="lab_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Basic weighted-average common shares outstanding</link:label>
    <link:label id="lab_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_label_en-US" xlink:label="lab_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Weighted Average Number of Shares Outstanding, Basic</link:label>
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    <link:label id="lab_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_f1226a08-da2c-4a55-b9bb-4cffb24b4aba_terseLabel_en-US" xlink:label="lab_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Revolving credit facility, basis spread on variable rate</link:label>
    <link:label id="lab_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_label_en-US" xlink:label="lab_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Debt Instrument, Basis Spread on Variable Rate</link:label>
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    <link:label id="lab_sm_LongTermLineOfCreditAndSeniorNotesNoncurrent_4098c108-b629-428a-a331-85993bc53a45_terseLabel_en-US" xlink:label="lab_sm_LongTermLineOfCreditAndSeniorNotesNoncurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Long-term Line of Credit and Senior Notes, Noncurrent</link:label>
    <link:label id="lab_sm_LongTermLineOfCreditAndSeniorNotesNoncurrent_label_en-US" xlink:label="lab_sm_LongTermLineOfCreditAndSeniorNotesNoncurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Long-term Line of Credit and Senior Notes, Noncurrent</link:label>
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    <link:loc xlink:type="locator" xlink:label="loc_sm_LongTermLineOfCreditAndSeniorNotesNoncurrent" xlink:href="sm-20200930.xsd#sm_LongTermLineOfCreditAndSeniorNotesNoncurrent"/>
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    <link:label id="lab_us-gaap_PlanNameDomain_004aeb9e-ace9-442f-af3c-078bf5b600c8_terseLabel_en-US" xlink:label="lab_us-gaap_PlanNameDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Plan Name [Domain]</link:label>
    <link:label id="lab_us-gaap_PlanNameDomain_label_en-US" xlink:label="lab_us-gaap_PlanNameDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Plan Name [Domain]</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PlanNameDomain" xlink:to="lab_us-gaap_PlanNameDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RevenueFromContractWithCustomerTextBlock_cf9462ce-0c86-47b3-b72a-fa81ea8bda6d_terseLabel_en-US" xlink:label="lab_us-gaap_RevenueFromContractWithCustomerTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Revenue from Contracts with Customers</link:label>
    <link:label id="lab_us-gaap_RevenueFromContractWithCustomerTextBlock_label_en-US" xlink:label="lab_us-gaap_RevenueFromContractWithCustomerTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Revenue from Contract with Customer [Text Block]</link:label>
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    <link:label id="lab_us-gaap_InterestPaidNet_7a658662-0fee-4614-8118-e951a8a78e0d_negatedLabel_en-US" xlink:label="lab_us-gaap_InterestPaidNet" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Cash paid for interest, net of capitalized interest</link:label>
    <link:label id="lab_us-gaap_InterestPaidNet_label_en-US" xlink:label="lab_us-gaap_InterestPaidNet" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Interest Paid, Excluding Capitalized Interest, Operating Activities</link:label>
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    <link:label id="lab_us-gaap_DerivativeLiabilityNotOffsetPolicyElectionDeduction_25528452-8d74-4c5e-a9df-3fde5cc6cf68_terseLabel_en-US" xlink:label="lab_us-gaap_DerivativeLiabilityNotOffsetPolicyElectionDeduction" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Derivative liabilities, amounts not offset in the accompanying balance sheets</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DerivativeLiabilityNotOffsetPolicyElectionDeduction" xlink:to="lab_us-gaap_DerivativeLiabilityNotOffsetPolicyElectionDeduction" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability_f06c06ec-c0b3-4884-a8e9-0ca7ce053a44_terseLabel_en-US" xlink:label="lab_us-gaap_RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Right-of-use assets obtained in exchange for new operating lease liabilities</link:label>
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    <link:label id="lab_us-gaap_LongTermDebtFairValue_f00a42ed-6e92-4a56-ab2e-9a70e83f5afd_terseLabel_en-US" xlink:label="lab_us-gaap_LongTermDebtFairValue" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Long-term Debt, Fair Value</link:label>
    <link:label id="lab_us-gaap_LongTermDebtFairValue_label_en-US" xlink:label="lab_us-gaap_LongTermDebtFairValue" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Long-term Debt, Fair Value</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LongTermDebtFairValue" xlink:to="lab_us-gaap_LongTermDebtFairValue" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_Revenues_98476397-48cf-4f7c-890d-e22fa463b61e_totalLabel_en-US" xlink:label="lab_us-gaap_Revenues" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Total operating revenues and other income</link:label>
    <link:label id="lab_us-gaap_Revenues_label_en-US" xlink:label="lab_us-gaap_Revenues" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Revenues</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Revenues" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_Revenues"/>
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    <link:label id="lab_sm_RevenueReceiptDaysAfterSale_365663d6-0152-4039-9d97-c22c0018f253_terseLabel_en-US" xlink:label="lab_sm_RevenueReceiptDaysAfterSale" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Revenue receipt, days after sale</link:label>
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    <link:label id="lab_us-gaap_IncomeTaxExpenseBenefit_9b1678e8-77c9-43e0-8fee-168d7a25705b_negatedLabel_en-US" xlink:label="lab_us-gaap_IncomeTaxExpenseBenefit" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Income tax (expense) benefit</link:label>
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    <link:label id="lab_sm_AccountsReceivablefromCustomersAbstract_11f51aeb-bc61-4e76-97ac-8416f051405c_terseLabel_en-US" xlink:label="lab_sm_AccountsReceivablefromCustomersAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Accounts Receivable from Customers [Abstract]</link:label>
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    <link:label id="lab_us-gaap_PaymentsToAcquireOilAndGasPropertyAndEquipment_2fbe33fc-736d-42d3-860b-b428e8b1746d_negatedLabel_en-US" xlink:label="lab_us-gaap_PaymentsToAcquireOilAndGasPropertyAndEquipment" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Acquisition of proved and unproved oil and gas properties</link:label>
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    <link:label id="lab_us-gaap_EarningsPerShareDiluted_afe31166-b7af-42e9-acf0-8092d3c9a94b_terseLabel_en-US" xlink:label="lab_us-gaap_EarningsPerShareDiluted" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Diluted net income (loss) per common share</link:label>
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    <link:label id="lab_sm_NGLSwapsContractYear2Member_af29fdae-8dba-4e66-b0b7-9bb22c9fcdb7_terseLabel_en-US" xlink:label="lab_sm_NGLSwapsContractYear2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">NGL Swaps Contract, 2021 [Member]</link:label>
    <link:label id="lab_sm_NGLSwapsContractYear2Member_label_en-US" xlink:label="lab_sm_NGLSwapsContractYear2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">NGL Swaps Contract, Year 2 [Member]</link:label>
    <link:label id="lab_sm_NGLSwapsContractYear2Member_documentation_en-US" xlink:label="lab_sm_NGLSwapsContractYear2Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">NGL Swaps Contract, Year 2</link:label>
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    <link:label id="lab_us-gaap_LongTermPurchaseCommitmentTable_0c42d423-96f8-4af3-a3d1-895b77e3c559_terseLabel_en-US" xlink:label="lab_us-gaap_LongTermPurchaseCommitmentTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Long-term Purchase Commitment [Table]</link:label>
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    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermPurchaseCommitmentTable" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LongTermPurchaseCommitmentTable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LongTermPurchaseCommitmentTable" xlink:to="lab_us-gaap_LongTermPurchaseCommitmentTable" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_LocalPhoneNumber_5a2a9c0d-cecf-4a1b-bfaf-8edcbb104d77_terseLabel_en-US" xlink:label="lab_dei_LocalPhoneNumber" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Local Phone Number</link:label>
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    <link:label id="lab_us-gaap_AccruedIncomeReceivableMember_229a6526-1e12-42ff-9e3b-7710f3e7ce84_terseLabel_en-US" xlink:label="lab_us-gaap_AccruedIncomeReceivableMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Accrued Income Receivable [Member]</link:label>
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    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccruedIncomeReceivableMember" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccruedIncomeReceivableMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AccruedIncomeReceivableMember" xlink:to="lab_us-gaap_AccruedIncomeReceivableMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DerivativeLineItems_2dff5eb4-a701-4540-94b2-57a9e005a4fa_terseLabel_en-US" xlink:label="lab_us-gaap_DerivativeLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Derivative Financial Instruments</link:label>
    <link:label id="lab_us-gaap_DerivativeLineItems_label_en-US" xlink:label="lab_us-gaap_DerivativeLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Derivative [Line Items]</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DerivativeLineItems" xlink:to="lab_us-gaap_DerivativeLineItems" xlink:type="arc" order="1"/>
    <link:label id="lab_sm_DerivativeOilBasisSwapTypeWeightedAverageContractPrice_f22bed19-3201-4874-8b18-021cf418ace5_terseLabel_en-US" xlink:label="lab_sm_DerivativeOilBasisSwapTypeWeightedAverageContractPrice" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Derivative, Oil Basis Swap Type, Weighted-Average Contract Price</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NonmonetaryTransactionGainLossRecognizedOnTransfer" xlink:to="lab_us-gaap_NonmonetaryTransactionGainLossRecognizedOnTransfer" xlink:type="arc" order="1"/>
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    <link:label id="lab_us-gaap_LiabilitiesNoncurrentAbstract_0b8f146b-9123-4de4-bf5a-082f0f2f739e_terseLabel_en-US" xlink:label="lab_us-gaap_LiabilitiesNoncurrentAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Noncurrent liabilities:</link:label>
    <link:label id="lab_us-gaap_LiabilitiesNoncurrentAbstract_label_en-US" xlink:label="lab_us-gaap_LiabilitiesNoncurrentAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Liabilities, Noncurrent [Abstract]</link:label>
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    <link:label id="lab_us-gaap_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentage_4c8d5bed-f18d-451a-998d-d9e149284a2a_terseLabel_en-US" xlink:label="lab_us-gaap_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentage" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Revolving credit facility, unused capacity, commitment fee rate</link:label>
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    <link:label id="lab_us-gaap_EarningsPerShareTextBlock_bb5b24cb-0baa-4609-95f3-783ee7d67120_terseLabel_en-US" xlink:label="lab_us-gaap_EarningsPerShareTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Earnings per Share</link:label>
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    <link:label id="lab_us-gaap_LiabilitiesCurrentAbstract_4f20d678-e72b-4c89-b86c-a994916c896d_terseLabel_en-US" xlink:label="lab_us-gaap_LiabilitiesCurrentAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Current liabilities:</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract" xlink:to="lab_us-gaap_LiabilitiesCurrentAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_sm_SeniorSecuredNotesMember_2c16f8bf-b362-4760-afa2-c9d3e9b0502a_terseLabel_en-US" xlink:label="lab_sm_SeniorSecuredNotesMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Senior Secured Notes [Member]</link:label>
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    <link:label id="lab_sm_CashPortionOfGainLossOnDerivativeInstrument_48be2a50-fd09-4bb4-adcc-d80fc8433133_terseLabel_en-US" xlink:label="lab_sm_CashPortionOfGainLossOnDerivativeInstrument" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Derivative settlement gain</link:label>
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