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  <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_NortheastSegmentMember" abstract="true" name="NortheastSegmentMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="smlp_PaymentsToAcquireCommonUnits" abstract="false" name="PaymentsToAcquireCommonUnits" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="smlp_PermianBasinSegmentMember" abstract="true" name="PermianBasinSegmentMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="smlp_DebtInstrumentIssuedAsAPercentageOfFaceValue" abstract="false" name="DebtInstrumentIssuedAsAPercentageOfFaceValue" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="smlp_ContractWithCustomerLiabilityCurrentAdditions" abstract="false" name="ContractWithCustomerLiabilityCurrentAdditions" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" 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_PartnersCapitalDecreaseFromTaxWithholdingFromPreferredStockExchange" abstract="false" name="PartnersCapitalDecreaseFromTaxWithholdingFromPreferredStockExchange" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="smlp_AssetBackedLendingFacilityMember" abstract="true" name="AssetBackedLendingFacilityMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="smlp_PartnersCapitalAccountIncreaseFromAssumptionOfNoncontrollingInterest" abstract="false" name="PartnersCapitalAccountIncreaseFromAssumptionOfNoncontrollingInterest" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="smlp_PartnersCapitalMember" abstract="true" name="PartnersCapitalMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="smlp_ChangeInContractWithCustomerLiabilityNoncurrentRollForward" abstract="true" name="ChangeInContractWithCustomerLiabilityNoncurrentRollForward" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <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_CreditAgreementMember" abstract="true" name="CreditAgreementMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="smlp_AccruedAndUnpaidDistributions" abstract="false" name="AccruedAndUnpaidDistributions" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="smlp_PartnersCapitalTable" abstract="true" name="PartnersCapitalTable" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType"/>
  <xs:element id="smlp_ScheduleOfPartnerUnitsActivityTableTableTextBlock" abstract="false" name="ScheduleOfPartnerUnitsActivityTableTableTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:textBlockItemType"/>
  <xs:element id="smlp_GainLossOnECPWarrantsAndOther" abstract="false" name="GainLossOnECPWarrantsAndOther" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
</xs:schema>
