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  <xs:element id="fet_IncreaseDecreaseInCostAndEstimatedProfitInExcessOfBillings" abstract="false" name="IncreaseDecreaseInCostAndEstimatedProfitInExcessOfBillings" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="fet_IncreaseDecreaseInAccountsPayableDeferredRevenueAndOtherAccruedLiabilities" abstract="false" name="IncreaseDecreaseInAccountsPayableDeferredRevenueAndOtherAccruedLiabilities" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="fet_PaymentOfCapitalLeaseObligations" abstract="false" name="PaymentOfCapitalLeaseObligations" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <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_ContractWithCustomerAssetCumulativeCatchUpAdjustmentToRevenueChangeInMeasureOfProgressPercent" abstract="false" name="ContractWithCustomerAssetCumulativeCatchUpAdjustmentToRevenueChangeInMeasureOfProgressPercent" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <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_ContractWithCustomerContractDuration" abstract="false" name="ContractWithCustomerContractDuration" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="fet_ScheduleOfFiniteLivedAndIndefiniteLivedIntangibleAssetsByMajorClassTable" abstract="true" name="ScheduleOfFiniteLivedAndIndefiniteLivedIntangibleAssetsByMajorClassTable" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType"/>
  <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_FiniteLivedAndIndefiniteLivedIntangibleAssetsLineItems" abstract="true" name="FiniteLivedAndIndefiniteLivedIntangibleAssetsLineItems" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="fet_A2029BondsMember" abstract="true" name="A2029BondsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <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_A2017CreditFacilityMember" abstract="true" name="A2017CreditFacilityMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="fet_U.S.LineMember" abstract="true" name="U.S.LineMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="fet_CreditFacilityUnusedPortionGreaterThan50Member" abstract="true" name="CreditFacilityUnusedPortionGreaterThan50Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="fet_CreditFacilityUnusedPortionLessThanOrEqualTo50Member" abstract="true" name="CreditFacilityUnusedPortionLessThanOrEqualTo50Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="fet_A2017CreditFacility12.5OfBorrowingBaseMember" abstract="true" name="A2017CreditFacility12.5OfBorrowingBaseMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="fet_SecuredOvernightFinancingRateSOFRFloorMember" abstract="true" name="SecuredOvernightFinancingRateSOFRFloorMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="fet_CORRARateMember" abstract="true" name="CORRARateMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="fet_CanadianSubsidiariesMember" abstract="true" name="CanadianSubsidiariesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="fet_DebtInstrumentCovenantLeverageRatioMaximum" abstract="false" name="DebtInstrumentCovenantLeverageRatioMaximum" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:pureItemType"/>
  <xs:element id="fet_DebtInstrumentCovenantMinimumLiquidityTestAmount" abstract="false" name="DebtInstrumentCovenantMinimumLiquidityTestAmount" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="fet_DebtInstrumentPurchasePricePercentageOfPrincipal" abstract="false" name="DebtInstrumentPurchasePricePercentageOfPrincipal" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:pureItemType"/>
  <xs:element id="fet_NumberOfBusinessDays" abstract="false" name="NumberOfBusinessDays" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:integerItemType"/>
  <xs:element id="fet_LineOfCreditFacilityMaturityExtensionThresholdPeriod" abstract="false" name="LineOfCreditFacilityMaturityExtensionThresholdPeriod" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="fet_LineOfCreditFacilityIncrementalCommitments" abstract="false" name="LineOfCreditFacilityIncrementalCommitments" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <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_DebtInstrumentFixedChargeCoverageRatio" abstract="false" name="DebtInstrumentFixedChargeCoverageRatio" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:pureItemType"/>
  <xs:element id="fet_DebtInstrumentFixedChargeCoverageRatioConsecutiveDaysThreshold" abstract="false" name="DebtInstrumentFixedChargeCoverageRatioConsecutiveDaysThreshold" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="fet_DrillingAndCompletionsSegmentMember" abstract="true" name="DrillingAndCompletionsSegmentMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="fet_ArtificialLiftAndDownholeSegmentMember" abstract="true" name="ArtificialLiftAndDownholeSegmentMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="fet_DrillingAndCompletionsMember" abstract="true" name="DrillingAndCompletionsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="fet_ArtificialLiftAndDownholeMember" abstract="true" name="ArtificialLiftAndDownholeMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="fet_DrillingMember" abstract="true" name="DrillingMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="fet_SubseaMember" abstract="true" name="SubseaMember" 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_CoiledTubingMember" abstract="true" name="CoiledTubingMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="fet_DownholeMember" abstract="true" name="DownholeMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <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_ValveSolutionsMember" abstract="true" name="ValveSolutionsMember" 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_EmployeesMember" abstract="true" name="EmployeesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="fet_NonEmployeeMembersOfBoardOfDirectorsMember" abstract="true" name="NonEmployeeMembersOfBoardOfDirectorsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="fet_TimeBasedRestrictedStockUnitsMember" abstract="true" name="TimeBasedRestrictedStockUnitsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="fet_TimeBasedRESMember" abstract="true" name="TimeBasedRESMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="fet_PerformanceRestrictedStockRelativeTSRMember" abstract="true" name="PerformanceRestrictedStockRelativeTSRMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="fet_PerformanceRestrictedStockEBITDAMember" abstract="true" name="PerformanceRestrictedStockEBITDAMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="fet_NumberOfPerformancePeriods" abstract="false" name="NumberOfPerformancePeriods" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:integerItemType"/>
  <xs:element id="fet_PercentageOfTargetUnitsGranted" abstract="false" name="PercentageOfTargetUnitsGranted" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="fet_JohnIvascuMember" abstract="true" name="JohnIvascuMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
</xs:schema>
