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  <xs:element id="oke_NaturalGasPipelinesMember" abstract="true" name="NaturalGasPipelinesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="oke_LeaseAssetsAndLiabilitiesInBalanceSheetTableTextBlock" abstract="false" name="LeaseAssetsAndLiabilitiesInBalanceSheetTableTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:textBlockItemType"/>
  <xs:element id="oke_MedfordIncidentMember" abstract="true" name="MedfordIncidentMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="oke_OtherComprehensiveIncomeLossPortionAttributabletoEquityMethodInvestmentsNetofTaxAttributabletoParent" abstract="false" name="OtherComprehensiveIncomeLossPortionAttributabletoEquityMethodInvestmentsNetofTaxAttributabletoParent" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="oke_NaturalGasLiquidsMember" abstract="true" name="NaturalGasLiquidsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="oke_A3.375NotesPayabledue2022Member" abstract="true" name="A3.375NotesPayabledue2022Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="oke_LineOfCreditFacilityOptionToIncreaseBorrowingCapacity" abstract="false" name="LineOfCreditFacilityOptionToIncreaseBorrowingCapacity" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="oke_RegulatedSegmentByNameAxis" abstract="true" name="RegulatedSegmentByNameAxis" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:dimensionItem" type="xbrli:stringItemType"/>
  <xs:element id="oke_ForwardStartingandTreasuryLockContractsDomain" abstract="true" name="ForwardStartingandTreasuryLockContractsDomain" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="oke_DerivativesByCommodityDomain" abstract="true" name="DerivativesByCommodityDomain" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="oke_BusinessInterruptionInsuranceTableTextBlock" abstract="false" name="BusinessInterruptionInsuranceTableTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:textBlockItemType"/>
  <xs:element id="oke_AccumulatedOtherComprehensiveIncomeLossCumulativeChangeinOtherComprehensiveIncomeLossfromEquityMethodInvestmentsEffectNetofTax" abstract="false" name="AccumulatedOtherComprehensiveIncomeLossCumulativeChangeinOtherComprehensiveIncomeLossfromEquityMethodInvestmentsEffectNetofTax" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="oke_ConsolidatedStatementsOfIncomeParentheticalAbstract" abstract="true" name="ConsolidatedStatementsOfIncomeParentheticalAbstract" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="oke_TransportationandStorageRevenueMember" abstract="true" name="TransportationandStorageRevenueMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="oke_IssuedUnderEquityAgreementMember" abstract="true" name="IssuedUnderEquityAgreementMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="oke_IntersegmentRevenuesbyNameAxis" abstract="true" name="IntersegmentRevenuesbyNameAxis" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:dimensionItem" type="xbrli:stringItemType"/>
  <xs:element id="oke_Amountofaccumulatedothercomprehensiveincomelossattributableprimarilytoforwardstartinginterestrateswaps." abstract="false" name="Amountofaccumulatedothercomprehensiveincomelossattributableprimarilytoforwardstartinginterestrateswaps." nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="oke_EquityInNetEarningsFromInvestmentsMember" abstract="true" name="EquityInNetEarningsFromInvestmentsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="oke_FairValueAccountingPolicyAbstract" abstract="true" name="FairValueAccountingPolicyAbstract" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="oke_TransactionTypeDomain" abstract="true" name="TransactionTypeDomain" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="oke_UnrealizedGainLossOnCashFlowHedgesNetOfTaxAccumulatedOtherComprehensiveIncomeLoss" abstract="false" name="UnrealizedGainLossOnCashFlowHedgesNetOfTaxAccumulatedOtherComprehensiveIncomeLoss" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="oke_A3.4NotesPayabledue2029Member" abstract="true" name="A3.4NotesPayabledue2029Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="oke_UnamortizedPortionofTerminatedSwaps" abstract="false" name="UnamortizedPortionofTerminatedSwaps" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="oke_ReceivablesRelatedToIncurredCostsAndLossesDomain" abstract="true" name="ReceivablesRelatedToIncurredCostsAndLossesDomain" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="oke_OtherComprehensiveIncomeLossPortionAttributabletoEquityMethodInvestmentsNetofTax" abstract="false" name="OtherComprehensiveIncomeLossPortionAttributabletoEquityMethodInvestmentsNetofTax" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="oke_A6.125NotesPayabledue2041Member" abstract="true" name="A6.125NotesPayabledue2041Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="oke_SellorMember" abstract="true" name="SellorMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="oke_LineOfCreditFacilitySwinglineSubfacility" abstract="false" name="LineOfCreditFacilitySwinglineSubfacility" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="oke_GatheringandExchangeServicesRevenueMember" abstract="true" name="GatheringandExchangeServicesRevenueMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="oke_PropertyDamageMember" abstract="true" name="PropertyDamageMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="oke_MedfordIncidentDomain" abstract="true" name="MedfordIncidentDomain" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="oke_InsuranceDeductibles" abstract="false" name="InsuranceDeductibles" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="oke_IntersegmentRevenuesbyNameDomain" abstract="true" name="IntersegmentRevenuesbyNameDomain" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="oke_A4.95NotesPayabledue2047Member" abstract="true" name="A4.95NotesPayabledue2047Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="oke_FinancialDerivativeInstrumentMember" abstract="true" name="FinancialDerivativeInstrumentMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="oke_UnconsolidatedAffiliatesMember" abstract="true" name="UnconsolidatedAffiliatesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="oke_CostOfSalesAndFuelAxis" abstract="true" name="CostOfSalesAndFuelAxis" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:dimensionItem" type="xbrli:stringItemType"/>
  <xs:element id="oke_ForwardStartingandTreasuryLockContractsAxis" abstract="true" name="ForwardStartingandTreasuryLockContractsAxis" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:dimensionItem" type="xbrli:stringItemType"/>
  <xs:element id="oke_NaturalGasPipelinesRegulatedMember" abstract="true" name="NaturalGasPipelinesRegulatedMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="oke_IndebtednessToAdjustedEBITDAFromAcquisitionsMaximum" abstract="false" name="IndebtednessToAdjustedEBITDAFromAcquisitionsMaximum" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:pureItemType"/>
  <xs:element id="oke_IncreaseDecreaseInCommodityExchangesAndImbalancesNet" abstract="false" name="IncreaseDecreaseInCommodityExchangesAndImbalancesNet" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="oke_DerivativeInstrumentByMethodForSettingNotionalAmountDomain" abstract="true" name="DerivativeInstrumentByMethodForSettingNotionalAmountDomain" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="oke_AdjustedEBITDA" abstract="false" name="AdjustedEBITDA" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="oke_A5.0NotesPayabledue2023Member" abstract="true" name="A5.0NotesPayabledue2023Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="oke_CommodityExchangesAndImbalancesLiabilitiesCurrent" abstract="false" name="CommodityExchangesAndImbalancesLiabilitiesCurrent" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="oke_A7.5NotesPayabledue2023Member" abstract="true" name="A7.5NotesPayabledue2023Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="oke_BusinessInterruptionInsuranceMember" abstract="true" name="BusinessInterruptionInsuranceMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="oke_AmountOfAccumulatedOtherComprehensiveIncomeLossAttributablePrimarilyToSettledInterestRateSwaps" abstract="false" name="AmountOfAccumulatedOtherComprehensiveIncomeLossAttributablePrimarilyToSettledInterestRateSwaps" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="oke_NGLandCondensateSalesMember" abstract="true" name="NGLandCondensateSalesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="oke_OtherComprehensiveIncomeLossBeforeReclassifications" abstract="false" name="OtherComprehensiveIncomeLossBeforeReclassifications" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="oke_OtherComprehensiveIncomeLossPortionAttributabletoEquityMethodInvestmentsTax" abstract="false" name="OtherComprehensiveIncomeLossPortionAttributabletoEquityMethodInvestmentsTax" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="oke_OtherComprehensiveIncomeLossReclassificationAdjustmentIncludedInNetIncomeNetOfTax" abstract="false" name="OtherComprehensiveIncomeLossReclassificationAdjustmentIncludedInNetIncomeNetOfTax" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="oke_CommodityExchangesAndImbalances" abstract="false" name="CommodityExchangesAndImbalances" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="oke_NoncustomerDomain" abstract="true" name="NoncustomerDomain" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="oke_ServicesMember" abstract="true" name="ServicesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="oke_VariableRateMember" abstract="true" name="VariableRateMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
</xs:schema>
