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  <xs:element id="smlp_DebtInstrumentRedemptionPriceOfferAmount" abstract="false" name="DebtInstrumentRedemptionPriceOfferAmount" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="smlp_DebtInstrumentTenderedAndValidlyAcceptedAndFullyDischargedAmount" abstract="false" name="DebtInstrumentTenderedAndValidlyAcceptedAndFullyDischargedAmount" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="smlp_DebtInstrumentCovenantExcessCashFlowOfferToPurchaseAssetSaleOfferExpired" abstract="false" name="DebtInstrumentCovenantExcessCashFlowOfferToPurchaseAssetSaleOfferExpired" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="smlp_DebtInstrumentNoticeOfRedemptionOnTenderOfferRedemptionAmount" abstract="false" name="DebtInstrumentNoticeOfRedemptionOnTenderOfferRedemptionAmount" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="smlp_DebtInstrumentRedemptionNoticeAmount" abstract="false" name="DebtInstrumentRedemptionNoticeAmount" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="smlp_DebtInstrumentsRedemptionPeriodOneMember" abstract="true" name="DebtInstrumentsRedemptionPeriodOneMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="smlp_DebtInstrumentsRedemptionPeriodTwoMember" abstract="true" name="DebtInstrumentsRedemptionPeriodTwoMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="smlp_DebtInstrumentRedemptionPeriodAfterTwoMember" abstract="true" name="DebtInstrumentRedemptionPeriodAfterTwoMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="smlp_MeadowlarkMidstreamGatheringSystemMember" abstract="true" name="MeadowlarkMidstreamGatheringSystemMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="smlp_A2015BlacktailReleaseMember" abstract="true" name="A2015BlacktailReleaseMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="smlp_NaturalResourceDamagesToFederalAndStateGovernmentsMember" abstract="true" name="NaturalResourceDamagesToFederalAndStateGovernmentsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="smlp_DamagesPayableToFederalGovernmentOverFiveYearsMember" abstract="true" name="DamagesPayableToFederalGovernmentOverFiveYearsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="smlp_DamagesPayableToStateGovernmentsOverSixYearsMember" abstract="true" name="DamagesPayableToStateGovernmentsOverSixYearsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="smlp_DamagesPayableToFederalCriminalOverFiveYearsMember" abstract="true" name="DamagesPayableToFederalCriminalOverFiveYearsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="smlp_EnvironmentalLossContingenciesPenaltiesAndFinesPaymentPeriod" abstract="false" name="EnvironmentalLossContingenciesPenaltiesAndFinesPaymentPeriod" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="smlp_AccrualForEnvironmentalLossContingenciesExpectedPayment" abstract="false" name="AccrualForEnvironmentalLossContingenciesExpectedPayment" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="smlp_SeniorNotesDue2025Member" abstract="true" name="SeniorNotesDue2025Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="smlp_SeniorNotesDueTwentyTwentySixMember" abstract="true" name="SeniorNotesDueTwentyTwentySixMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="smlp_SeniorUnsecuredNotesDueTwentyTwentySixMember" abstract="true" name="SeniorUnsecuredNotesDueTwentyTwentySixMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="smlp_LimitedPartnerCommonUnitsMember" abstract="true" name="LimitedPartnerCommonUnitsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="smlp_PartnersCapitalAccountUnitsIssuedForWarrantExercises" abstract="false" name="PartnersCapitalAccountUnitsIssuedForWarrantExercises" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:sharesItemType"/>
  <xs:element id="smlp_PartnersCapitalTable" abstract="true" name="PartnersCapitalTable" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType"/>
  <xs:element id="smlp_LondonInterbankOfferRateLIBORMember" abstract="true" name="LondonInterbankOfferRateLIBORMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="smlp_PartnersCapitalLineItems" abstract="true" name="PartnersCapitalLineItems" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="smlp_SeriesAPreferredUnitsMember" abstract="true" name="SeriesAPreferredUnitsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="smlp_PreferredUnitExchangeOffer" abstract="false" name="PreferredUnitExchangeOffer" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:sharesItemType"/>
  <xs:element id="smlp_PreferredUnitAndStockCorporateReorganization" abstract="false" name="PreferredUnitAndStockCorporateReorganization" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:sharesItemType"/>
  <xs:element id="smlp_PartnersCapitalIssuanceCosts" abstract="false" name="PartnersCapitalIssuanceCosts" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="smlp_CommonUnitsMember" abstract="true" name="CommonUnitsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="smlp_IncrementalCommonSharesAttributableToDilutiveEffectOfConversionAndEliminationOfNoncontrollingInterestNetIncome" abstract="false" name="IncrementalCommonSharesAttributableToDilutiveEffectOfConversionAndEliminationOfNoncontrollingInterestNetIncome" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:sharesItemType"/>
  <xs:element id="smlp_LongTermIncentivePlanMember" abstract="true" name="LongTermIncentivePlanMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="smlp_SMCLongTermIncentivePlanMember" abstract="true" name="SMCLongTermIncentivePlanMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="smlp_PhantomShareUnitsAndAssociatedDistributionEquivalentRightsMember" abstract="true" name="PhantomShareUnitsAndAssociatedDistributionEquivalentRightsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="smlp_ShareBasedCompensationArrangementByShareBasedPaymentAwardGrantDateFairValue" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardGrantDateFairValue" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="smlp_ShareBasedCompensationArrangementByShareBasedPaymentAwardStockConversionConversionRatio" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardStockConversionConversionRatio" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:pureItemType"/>
  <xs:element id="smlp_NumberOfDirectors" abstract="false" name="NumberOfDirectors" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:integerItemType"/>
  <xs:element id="smlp_ShareBasedCompensationArrangementByShareBasedPaymentAwardCanceledAndConvertedShares" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardCanceledAndConvertedShares" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:sharesItemType"/>
  <xs:element id="smlp_ShareBasedCompensationArrangementByShareBasedPaymentAwardVestedAwardAssumedPayoutPercentage" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardVestedAwardAssumedPayoutPercentage" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:pureItemType"/>
  <xs:element id="smlp_EffectiveIncomeTaxRateReconciliationCorporateReorganization" abstract="false" name="EffectiveIncomeTaxRateReconciliationCorporateReorganization" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="smlp_EffectiveIncomeTaxRateReconciliationTransactionCosts" abstract="false" name="EffectiveIncomeTaxRateReconciliationTransactionCosts" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="smlp_EffectiveIncomeTaxRateReconciliationRemovalOfNoncontrollingInterests" abstract="false" name="EffectiveIncomeTaxRateReconciliationRemovalOfNoncontrollingInterests" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="smlp_EffectiveIncomeTaxRateReconciliationRemovalOfNontaxableIncome" abstract="false" name="EffectiveIncomeTaxRateReconciliationRemovalOfNontaxableIncome" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="smlp_OfficeSpaceMember" abstract="true" name="OfficeSpaceMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="smlp_IncrementalBorrowingRate" abstract="false" name="IncrementalBorrowingRate" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:percentItemType"/>
  <xs:element id="smlp_FinanceAndOperatingLeaseRightOfUseAsset" abstract="false" name="FinanceAndOperatingLeaseRightOfUseAsset" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="smlp_LeaseLiabilitiesCurrentAbstract" abstract="true" name="LeaseLiabilitiesCurrentAbstract" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="smlp_FinanceAndOperatingLeaseLiabilityCurrent" abstract="false" name="FinanceAndOperatingLeaseLiabilityCurrent" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="smlp_LeaseLiabilitiesNoncurrentAbstract" abstract="true" name="LeaseLiabilitiesNoncurrentAbstract" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="smlp_FinanceAndOperatingLeaseLiabilityNoncurrent" abstract="false" name="FinanceAndOperatingLeaseLiabilityNoncurrent" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="smlp_LesseeOperatingLeaseLiabilityPaymentsDueYearSix" abstract="false" name="LesseeOperatingLeaseLiabilityPaymentsDueYearSix" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="smlp_LesseeOperatingLeaseLiabilityPaymentsDueAfterYearSix" abstract="false" name="LesseeOperatingLeaseLiabilityPaymentsDueAfterYearSix" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="smlp_FinanceLeaseLiabilityPaymentsDueYearSix" abstract="false" name="FinanceLeaseLiabilityPaymentsDueYearSix" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="smlp_FinanceLeaseLiabilityPaymentsDueAfterYearSix" abstract="false" name="FinanceLeaseLiabilityPaymentsDueAfterYearSix" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="smlp_AdjustedEarningsBeforeInterestTaxesDepreciationAndAmortization" abstract="false" name="AdjustedEarningsBeforeInterestTaxesDepreciationAndAmortization" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="smlp_RockiesBSegmentMember" abstract="true" name="RockiesBSegmentMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="smlp_RockiesCSegmentMember" abstract="true" name="RockiesCSegmentMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="smlp_ReconciliationOfNetIncomeToEBITDAAdditionsAbstract" abstract="true" name="ReconciliationOfNetIncomeToEBITDAAdditionsAbstract" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="smlp_CorporateAndOtherExpenses" abstract="false" name="CorporateAndOtherExpenses" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="smlp_AdjustedEarningsBeforeInterestTaxesDepreciationAndAmortizationProportionalEquityMethodInvestmentAdjustment" abstract="false" name="AdjustedEarningsBeforeInterestTaxesDepreciationAndAmortizationProportionalEquityMethodInvestmentAdjustment" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="smlp_AdjustmentsRelatedToCapitalReimbursementActivity" abstract="false" name="AdjustmentsRelatedToCapitalReimbursementActivity" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="smlp_MoonriseMidstreamLLCMember" abstract="true" name="MoonriseMidstreamLLCMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
</xs:schema>
