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  <xs:element id="smlp_ProfitLossExcludingSubsidiaryIncome" abstract="false" name="ProfitLossExcludingSubsidiaryIncome" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="smlp_ChangeInContractWithCustomerLiabilityNoncurrentRollForward" abstract="true" name="ChangeInContractWithCustomerLiabilityNoncurrentRollForward" 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_CommonUnitsMember" abstract="true" name="CommonUnitsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="smlp_SeniorSecuredNotesDue2026Member" abstract="true" name="SeniorSecuredNotesDue2026Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="smlp_RockiesSegmentMember" abstract="true" name="RockiesSegmentMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="smlp_SecuredNotesIndenture2026Member" abstract="true" name="SecuredNotesIndenture2026Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <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_SeniorNotesDue2026Member" abstract="true" name="SeniorNotesDue2026Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="smlp_ContributedCapitalFromPreferredUnitsExchange" abstract="false" name="ContributedCapitalFromPreferredUnitsExchange" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="smlp_DebtInstrumentCovenantExcessCashFlowOfferToPurchaseBasisPointIncreasePeriodTwo" abstract="false" name="DebtInstrumentCovenantExcessCashFlowOfferToPurchaseBasisPointIncreasePeriodTwo" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="smlp_DistributionOfAllAvailableCashMaximumPeriodFollowingEndOfQuarter" abstract="false" name="DistributionOfAllAvailableCashMaximumPeriodFollowingEndOfQuarter" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="smlp_DebtInstrumentCovenantExcessCashFlowOfferToPurchasePeriodOne" abstract="false" name="DebtInstrumentCovenantExcessCashFlowOfferToPurchasePeriodOne" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="smlp_LongTermIncentivePlanMember" abstract="true" name="LongTermIncentivePlanMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="smlp_DebtInstrumentCovenantFirstLienNetLeverageRatio" abstract="false" name="DebtInstrumentCovenantFirstLienNetLeverageRatio" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:pureItemType"/>
</xs:schema>
