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  <xs:element id="fet_ContractwithCustomerLiabilityCumulativeCatchupAdjustmenttoRevenueChangeinMeasureofProgressPercent" abstract="false" name="ContractwithCustomerLiabilityCumulativeCatchupAdjustmenttoRevenueChangeinMeasureofProgressPercent" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="fet_DrillingTechnologiesMember" abstract="true" name="DrillingTechnologiesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="fet_CompletionsMember" abstract="true" name="CompletionsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="fet_ContractWithCustomerLiabilityDeferredRevenue" abstract="false" name="ContractWithCustomerLiabilityDeferredRevenue" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="fet_ContractWithCustomerContractDuration" abstract="false" name="ContractWithCustomerContractDuration" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="fet_DebtConversionOriginalDebtInterestRateOfDebtPercentPayableInCashOrAdditionalNotes" abstract="false" name="DebtConversionOriginalDebtInterestRateOfDebtPercentPayableInCashOrAdditionalNotes" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="fet_ProductionEquipmentMember" abstract="true" name="ProductionEquipmentMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="fet_PaymentsRelatedToBusinessAcquisitionsAndDispositions" abstract="false" name="PaymentsRelatedToBusinessAcquisitionsAndDispositions" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="fet_ProductionMember" abstract="true" name="ProductionMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="fet_DebtInstrumentConvertibleTradingPeriodConversionPrice" abstract="false" name="DebtInstrumentConvertibleTradingPeriodConversionPrice" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types:perShareItemType"/>
  <xs:element id="fet_DebtInstrumentFixedChargeCoverageRatio" abstract="false" name="DebtInstrumentFixedChargeCoverageRatio" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:pureItemType"/>
  <xs:element id="fet_OtherDebtMember" abstract="true" name="OtherDebtMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="fet_CoiledTubingMember" abstract="true" name="CoiledTubingMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="fet_DebtConversionOriginalDebtInterestRateOfDebtPercentPayableInCash" abstract="false" name="DebtConversionOriginalDebtInterestRateOfDebtPercentPayableInCash" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="fet_SummaryOfIntangibleAssetsTableTextBlock" abstract="false" name="SummaryOfIntangibleAssetsTableTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:textBlockItemType"/>
  <xs:element id="fet_DrillingAndDownholeMember" abstract="true" name="DrillingAndDownholeMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="fet_ContractWithCustomerAssetCostsinExcessofBillings" abstract="false" name="ContractWithCustomerAssetCostsinExcessofBillings" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="fet_AssetAcquisitionTermOfExpectedPayment" abstract="false" name="AssetAcquisitionTermOfExpectedPayment" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="fet_A125OfBorrowingBaseMember" abstract="true" name="A125OfBorrowingBaseMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="fet_DebtInstrumentFixedChargeCoverageRatioConsecutiveDaysThreshold" abstract="false" name="DebtInstrumentFixedChargeCoverageRatioConsecutiveDaysThreshold" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="fet_PatentsAndTechnologyMember" abstract="true" name="PatentsAndTechnologyMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="fet_AdjustmentsToAdditionalPaidInCapitalLiabilityAwardsConvertedToShareSettled" abstract="false" name="AdjustmentsToAdditionalPaidInCapitalLiabilityAwardsConvertedToShareSettled" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="fet_PaymentsForCapitalLeaseObligations" abstract="false" name="PaymentsForCapitalLeaseObligations" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="fet_A2021NotesMember" abstract="true" name="A2021NotesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="fet_ContractwithCustomerAssetCumulativeCatchupAdjustmenttoRevenueChangeinMeasureofProgressPercent" abstract="false" name="ContractwithCustomerAssetCumulativeCatchupAdjustmenttoRevenueChangeinMeasureofProgressPercent" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="fet_A2025NotesMember" abstract="true" name="A2025NotesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="fet_CDORRateMember" abstract="true" name="CDORRateMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="fet_EuropeAndAfricaMember" abstract="true" name="EuropeAndAfricaMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="fet_ValveSolutionsMember" abstract="true" name="ValveSolutionsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="fet_StimulationandInterventionMember" abstract="true" name="StimulationandInterventionMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="fet_DebtInstrumentPercentageOfBorrowingBase" abstract="false" name="DebtInstrumentPercentageOfBorrowingBase" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="fet_IncreaseDecreaseInDeferredLoanCosts" abstract="false" name="IncreaseDecreaseInDeferredLoanCosts" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="fet_PaymentsForRepurchaseOfSeniorNotes" abstract="false" name="PaymentsForRepurchaseOfSeniorNotes" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="fet_DebtInstrumentMandatorilyConvertibleFaceAmount" abstract="false" name="DebtInstrumentMandatorilyConvertibleFaceAmount" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="fet_ScheduleOfFiniteLivedAndIndefiniteLivedIntangibleAssetsByMajorClassTable" abstract="true" name="ScheduleOfFiniteLivedAndIndefiniteLivedIntangibleAssetsByMajorClassTable" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType"/>
  <xs:element id="fet_ContingentRestrictedStockMember" abstract="true" name="ContingentRestrictedStockMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="fet_A80OfBorrowingBaseMember" abstract="true" name="A80OfBorrowingBaseMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="fet_FiniteLivedAndIndefiniteLivedIntangibleAssetsLineItems" abstract="true" name="FiniteLivedAndIndefiniteLivedIntangibleAssetsLineItems" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
</xs:schema>
