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  <xs:element id="obnk_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentProvisionForOffBalanceSheetContingencies" abstract="false" name="BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentProvisionForOffBalanceSheetContingencies" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
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  <xs:element id="obnk_ConstructionLandandLandDevelopmentLoansMember" abstract="true" name="ConstructionLandandLandDevelopmentLoansMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="obnk_BusinessCombinationRecognizedIdentifiableAssetAcquiredAndLiabilityAssumedInterestBearingDeposits" abstract="false" name="BusinessCombinationRecognizedIdentifiableAssetAcquiredAndLiabilityAssumedInterestBearingDeposits" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="obnk_LincolnAgencyLLCAndPulleyWhiteInsuranceAgencyIncMember" abstract="true" name="LincolnAgencyLLCAndPulleyWhiteInsuranceAgencyIncMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="obnk_PaymentsOfFHLBankBorrowingsLongTermAdvancesFinancingActivities" abstract="false" name="PaymentsOfFHLBankBorrowingsLongTermAdvancesFinancingActivities" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
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  <xs:element id="obnk_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOperatingLeaseRightOfUseAssets" abstract="false" name="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOperatingLeaseRightOfUseAssets" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
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  <xs:element id="obnk_AssetsAcquiredAbstract" abstract="true" name="AssetsAcquiredAbstract" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
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  <xs:element id="obnk_FederalHomeLoanBankMember" abstract="true" name="FederalHomeLoanBankMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
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  <xs:element id="obnk_MortgageBankingOperationsTableTextBlock" abstract="false" name="MortgageBankingOperationsTableTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:textBlockItemType"/>
  <xs:element id="obnk_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForAmortizationOfUnrealizedLossesOnAvailableForSaleSecuritiesTransferredToHeldToMaturityBeforeTax" abstract="false" name="OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForAmortizationOfUnrealizedLossesOnAvailableForSaleSecuritiesTransferredToHeldToMaturityBeforeTax" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="obnk_FinancingReceivablePurchasedWithCreditDeteriorationLoansAcquired" abstract="false" name="FinancingReceivablePurchasedWithCreditDeteriorationLoansAcquired" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="obnk_FederalHomeLoanBankAdvanceTwoMember" abstract="true" name="FederalHomeLoanBankAdvanceTwoMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="obnk_MortgageServicingRightHedgeImpact" abstract="false" name="MortgageServicingRightHedgeImpact" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
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  <xs:element id="obnk_ForwardCommitmenttoSellMember" abstract="true" name="ForwardCommitmenttoSellMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="obnk_BankingRegulationAbstract" abstract="true" name="BankingRegulationAbstract" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
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  <xs:element id="obnk_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentDeferredTaxAssets" abstract="false" name="BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentDeferredTaxAssets" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="obnk_ForwardCommitmenttoPurchaseMember" abstract="true" name="ForwardCommitmenttoPurchaseMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="obnk_LoansAndLeasesReceivableImpairedInterestOnNonaccrualLoans" abstract="false" name="LoansAndLeasesReceivableImpairedInterestOnNonaccrualLoans" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
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  <xs:element id="obnk_BusinessAcquisitionEquityInterestsIssuedOrIssuableNumberOfSharesConverted" abstract="false" name="BusinessAcquisitionEquityInterestsIssuedOrIssuableNumberOfSharesConverted" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:sharesItemType"/>
  <xs:element id="obnk_GovernmentNationalMortgageAssociationRepurchaseAsset" abstract="false" name="GovernmentNationalMortgageAssociationRepurchaseAsset" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
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  <xs:element id="obnk_MortgageBankingRevenueOrigination" abstract="false" name="MortgageBankingRevenueOrigination" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
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  <xs:element id="obnk_OfficeandOperationsExpense" abstract="false" name="OfficeandOperationsExpense" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="obnk_DebtSecuritiesFVNICost" abstract="false" name="DebtSecuritiesFVNICost" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
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  <xs:element id="obnk_BusinessCombinationRecognizedIdentifiableAssetAcquiredAndLiabilityAssumedNoninterestBearingDeposits" abstract="false" name="BusinessCombinationRecognizedIdentifiableAssetAcquiredAndLiabilityAssumedNoninterestBearingDeposits" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
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  <xs:element id="obnk_NotesPayableRelatedPartiesTransfersAndChanges" abstract="false" name="NotesPayableRelatedPartiesTransfersAndChanges" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="obnk_FinancingReceivableAllowanceForCreditLossRecoveryOriginatedFourYearsBeforeLatestFiscalYear" abstract="false" name="FinancingReceivableAllowanceForCreditLossRecoveryOriginatedFourYearsBeforeLatestFiscalYear" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="obnk_MortgageBankingRevenue" abstract="false" name="MortgageBankingRevenue" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="obnk_ResidentialRealEstateLoanMember" abstract="true" name="ResidentialRealEstateLoanMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="obnk_PaymentsForProceedsFromOtherInvestments" abstract="false" name="PaymentsForProceedsFromOtherInvestments" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="obnk_EffectiveIncomeTaxReconciliationTaxExemptIncomeBankOwnedLifeInsuranceIncome" abstract="false" name="EffectiveIncomeTaxReconciliationTaxExemptIncomeBankOwnedLifeInsuranceIncome" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
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  <xs:element id="obnk_FederalHomeLoanBankAdvancesandSecuritiesSoldUnderAgreementstoRepurchaseFairValue" abstract="false" name="FederalHomeLoanBankAdvancesandSecuritiesSoldUnderAgreementstoRepurchaseFairValue" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
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  <xs:element id="obnk_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesSecuritiesSoldUnderAgreementsToRepurchase" abstract="false" name="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesSecuritiesSoldUnderAgreementsToRepurchase" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
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</xs:schema>
