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  <xs:element id="mplx_MarkWestEMGJeffersonDryGasGatheringCompanyL.L.C.Member" abstract="true" name="MarkWestEMGJeffersonDryGasGatheringCompanyL.L.C.Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="mplx_MarkWestUticaEMGMember" abstract="true" name="MarkWestUticaEMGMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="mplx_SherwoodMidstreamLLCMember" abstract="true" name="SherwoodMidstreamLLCMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="mplx_OtherVIEsandNonVIEsMember" abstract="true" name="OtherVIEsandNonVIEsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="mplx_BakkenPipelineSystemMember" abstract="true" name="BakkenPipelineSystemMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="mplx_TexasCityLogisticsLLCMember" abstract="true" name="TexasCityLogisticsLLCMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="mplx_EquityMethodInvestmentsIncludingHeldForSale" abstract="false" name="EquityMethodInvestmentsIncludingHeldForSale" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="mplx_SalesRevenueGoodsRelatedPartyNetZero" abstract="false" name="SalesRevenueGoodsRelatedPartyNetZero" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="mplx_MarathonPetroleumCorporationMember" abstract="true" name="MarathonPetroleumCorporationMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="mplx_AccountsPayableCurrentRelatedParty" abstract="false" name="AccountsPayableCurrentRelatedParty" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="mplx_OperatingLeaseLiabilityNoncurrentRelatedParty" abstract="false" name="OperatingLeaseLiabilityNoncurrentRelatedParty" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="mplx_StockholdersEquityTable" abstract="true" name="StockholdersEquityTable" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType"/>
  <xs:element id="mplx_StockholdersEquityLineItems" abstract="true" name="StockholdersEquityLineItems" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="mplx_AdjustedEBITDA" abstract="false" name="AdjustedEBITDA" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="mplx_CapitalExpenditures" abstract="false" name="CapitalExpenditures" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="mplx_InterestAndOtherFinancialCosts" abstract="false" name="InterestAndOtherFinancialCosts" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="mplx_DistributionsadjustmentsRelatedToEquityMethodInvestments" abstract="false" name="DistributionsadjustmentsRelatedToEquityMethodInvestments" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="mplx_AdjustedEBITDAattributabletononcontrollinginterests" abstract="false" name="AdjustedEBITDAattributabletononcontrollinginterests" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="mplx_FairValueInputsAssetsandLiabilitiesQuantitativeInformationTable" abstract="true" name="FairValueInputsAssetsandLiabilitiesQuantitativeInformationTable" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType"/>
  <xs:element id="mplx_FairValueInputsAssetsandLiabilitiesQuantitativeInformationLineItems" abstract="true" name="FairValueInputsAssetsandLiabilitiesQuantitativeInformationLineItems" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="mplx_FairValueInputsProbabilityOfRenewal" abstract="false" name="FairValueInputsProbabilityOfRenewal" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="mplx_NumberofRenewals" abstract="false" name="NumberofRenewals" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:pureItemType"/>
  <xs:element id="mplx_PurchasedproductcostsMember" abstract="true" name="PurchasedproductcostsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="mplx_ProductSalesMember" abstract="true" name="ProductSalesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="mplx_ServiceRevenueProductRelatedMember" abstract="true" name="ServiceRevenueProductRelatedMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="mplx_DerivativeInstrumentsNotDesignatedasHedgingInstrumentsRealizedGainLossNet" abstract="false" name="DerivativeInstrumentsNotDesignatedasHedgingInstrumentsRealizedGainLossNet" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="mplx_ANDXLPMember" abstract="true" name="ANDXLPMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="mplx_MPLXRevolvingCreditFacilityDueJuly2027Member" abstract="true" name="MPLXRevolvingCreditFacilityDueJuly2027Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="mplx_MPLXRevolvingCreditFacilityDueApril2031Member" abstract="true" name="MPLXRevolvingCreditFacilityDueApril2031Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="mplx_SwingLineLoanMember" abstract="true" name="SwingLineLoanMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="mplx_LineOfCreditFacilityRemainingBorrowingCapacityPercentage" abstract="false" name="LineOfCreditFacilityRemainingBorrowingCapacityPercentage" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="mplx_SeniorNoteDueApril2036Member" abstract="true" name="SeniorNoteDueApril2036Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="mplx_SeniorNoteDueApril2056Member" abstract="true" name="SeniorNoteDueApril2056Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="mplx_SeniorNotesDueMarch2026Member" abstract="true" name="SeniorNotesDueMarch2026Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="mplx_PercentofPar" abstract="false" name="PercentofPar" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="mplx_OtherFinancialCosts" abstract="false" name="OtherFinancialCosts" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="mplx_ContractBalancesTable" abstract="true" name="ContractBalancesTable" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType"/>
  <xs:element id="mplx_ContractwithCustomerAssetIncreaseDecrease" abstract="false" name="ContractwithCustomerAssetIncreaseDecrease" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="mplx_ContractWithCustomerAssetIncreaseDecreaseNoncurrent" abstract="false" name="ContractWithCustomerAssetIncreaseDecreaseNoncurrent" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="mplx_ContractWithCustomerNonCurrentAssetReclassifiedToReceivable" abstract="false" name="ContractWithCustomerNonCurrentAssetReclassifiedToReceivable" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="mplx_DeferredRevenueFromContractsWithCustomersCurrent" abstract="false" name="DeferredRevenueFromContractsWithCustomersCurrent" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="mplx_DeferredRevenueNoncurrentPeriodIncreaseDecrease" abstract="false" name="DeferredRevenueNoncurrentPeriodIncreaseDecrease" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="mplx_DeferredRevenueNoncurrentRevenueRecognized" abstract="false" name="DeferredRevenueNoncurrentRevenueRecognized" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="mplx_DeferredRevenueFromContractsWithCustomersNoncurrent" abstract="false" name="DeferredRevenueFromContractsWithCustomersNoncurrent" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="mplx_ContributionOfNetAssets" abstract="false" name="ContributionOfNetAssets" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="mplx_IncreaseDecreaseInAccrualsForCapitalExpenditures" abstract="false" name="IncreaseDecreaseInAccrualsForCapitalExpenditures" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="mplx_CommitmentsAndContingenciesTable" abstract="true" name="CommitmentsAndContingenciesTable" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType"/>
  <xs:element id="mplx_CommitmentsAndContingenciesLineItems" abstract="true" name="CommitmentsAndContingenciesLineItems" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
</xs:schema>
