油層物理油藏工程-課件chap

1.2SolutionandSeparationprocessinagas-oilsystem

(油氣體系的溶解與分離)SUNRen-yuanSchoolofPetroleumEngineeringSep.,2009ProvincialBilingualTeachingDemonstrationCourseContentsSolubility(溶解度)ofgasinoilEquilibriumRelations(相態(tài)方程)SeparationofgasandoilProvincialBilingualTeachingDemonstrationCourse1Solubility(溶解度)ofgasinoil1.1Henry’sLaw(亨利定律)Rs=αPRs－Solubilityofagas,thevolumeofgasdissolvedinaunitvolumeofliquidatpressurep,(standard)m3/m3；P－absolutePressure,MPa；α－Solubilityfactor(溶解系數(shù)),(standard)m3/(m3·MPa)Solubilityofagasinaliquidisdirectlyproportionaltothesystempressure.ProvincialBilingualTeachingDemonstrationCourse1.2SolutionofNaturalGasinOilanditsinfluencingfactors

1.2.1SolutionofNaturalGasinOilSolubilityofdifferentgasesincrudeoilNotice：

Henry’slawisapplicabletothegas-liquidsystemwheregasandliquiddifferconsiderablyintheirproperties.ProvincialBilingualTeachingDemonstrationCourse

1.2.1SolutionofNaturalGasinOilTheheavierhydrocarbonshavehighersolubilitiesthanthelighterhydrocarbons.ProvincialBilingualTeachingDemonstrationCourse

1.2.2factorsinfluencingGassolubilityinOilNogasavailableSolutionoflighterhydrocarbons,lowαSolutionofheavierhydrocarbons,highαProvincialBilingualTeachingDemonstrationCourse

1.2.2factorsinfluencingGassolubilityinOilThesolubilityofnaturalgasincrudeoildependsonthepressure,thetemperatureandthecompositionsofboththenaturalgasandthecrudeoil.①T=C，P↗，Rs↗；②P=C,T↗，Rs↘；ProvincialBilingualTeachingDemonstrationCourse

1.2.2factorsinfluencingGassolubilityinOilThesolubilityincreaseswiththemolecularweightofgas.

Thesolubilityincreasesasthecompositionsofthegasandcrudeoilapproacheachother.ProvincialBilingualTeachingDemonstrationCourse2EquilibriumEquations(相態(tài)方程)2.1DerivationofEquilibriumequations1molemixtureofknowncompositioncomponentsmolefractionc1n1c2n2……cini……cmnmProvincialBilingualTeachingDemonstrationCourse2.1DerivationofEquilibriumequationsNl,Ng---thetotalnumberofmolesofliquidandgas.ni--themolefractionoftheithcomponentinthetotalmixture,xi,yi---themolefractionoftheithcomponentintheliquidandgas.ProvincialBilingualTeachingDemonstrationCourse2.1DerivationofEquilibriumequationski=yi/xiEquilibriumratio/equilibriumconstant(平衡比/平衡常數(shù)orProvincialBilingualTeachingDemonstrationCourseUsage:tocalculationdewpoint,bubblepoint,thequantitiesandcompositionsofthegasandliquidatequilibrium.Trialanderrormethod2.1DerivationofEquilibriumequationsProvincialBilingualTeachingDemonstrationCourse2.2ApplicationofEquilibriumEquations(1)Calculatethebubblepoint(泡點壓力)：

Ng=0Nl=1Assumeaninitialvalueofpb,determineki,calculate,if,wegettherightpb.Otherwise,tryanothervalue,untilProvincialBilingualTeachingDemonstrationCourse2.2ApplicationofEquilibriumEquations(2)Calculatethedewpoint(露點壓力)：

Ng=1Nl=0ProvincialBilingualTeachingDemonstrationCourse2.3EquilibriumConstant(平衡常數(shù))Equilibriumconstant/Equilibriumratio(平衡比/平衡常數(shù))ki

thedistributionratioofcomponentiinthegasphaseandliquidphasewhenthesetwophasesareatequilibriumatgivenpandT.

在一定的溫度和壓力下，系統(tǒng)中氣液兩相達到熱力學(xué)平衡時，組分i在氣相和液相中的分配比例yi，Xi----themolefractionsofthecomponentiinthegasphaseandliquidphaserespectively

ProvincialBilingualTeachingDemonstrationCourseNoheatingeffectwhenthecomponentsaremixed;Thevolumeoftheidealsolutionequalstothesumofthevolumesthecomponents.Theintermolecularforcesofattractionandrepulsionarethesamebetweenmolecules.2.3.1idealsolution

Theidealassumptionsonlyapplytolowpressuresandmoderatetemperatures,chemicallyandphysicallysimilarcomponentsandbehaviourbelowthecriticalpoint2.3EquilibriumConstant(平衡常數(shù))ProvincialBilingualTeachingDemonstrationCourse(1)Raoult‘sequation(拉烏爾方程)

(2)Dalton‘sequation(道爾頓方程)

Thepartialpressure(分壓)ofacomponentinthegasisequaltotheproductofthemolefraction,xiintheliquid,multipliedbythevaporpressureofthepurecomponentpvi.Thepartialpressureofacomponentpiisequaltothemolefractionofthatcomponentinthegasyi,timesthetotalpressureofthesystemp.ProvincialBilingualTeachingDemonstrationCourseForanidealsolution,theequilibriumratioofeachcomponentissimplydependsonpressureandtemperature.ProvincialBilingualTeachingDemonstrationCourse2.3.2Realsolution

Theequilibriumratioforacomponentofarealsolutionisdependentnotonlyonthetemperatureandpressure,butalsoon

thecomposition

ofthesystem.UsuallydeterminedbyexperimentsFig.1.2.6Comparisonofequilibriumratiosat30℃for6.8and34MPaconvergencepressure(FromNGAA)ProvincialBilingualTeachingDemonstrationCourseProvincialBilingualTeachingDemonstrationCourse3SeparationofgasfromoilThemannerofseparation:(1)Flashvaporization(接觸分離）

(2)StageSeparation(多級分離)(3)DifferentialVaporization(微分分離)

Theprocessinwhichthepressureonaliquidisreducedsuddenly,causingaflashseparationofgasfromoilandanequilibriumbetweenoilandgasisestablishedimmediately.

使油藏?zé)N類體系從油藏壓力和溫度狀態(tài)瞬時變到某一特定壓力和溫度狀態(tài)，實現(xiàn)油氣分離，并迅速達到相平衡的過程。3.1Flashvaporization(閃蒸脫氣、一次脫氣、接觸分離)ProvincialBilingualTeachingDemonstrationCourse3.1Flashvaporization(閃蒸脫氣、一次脫氣、接觸分離)Features:1)Theoilandgaskeepincontact2)ThecompositionofthesystemremainsunchangedProvincialBilingualTeachingDemonstrationCourse3.1FlashvaporizationbubblepointProvincialBilingualTeachingDemonstrationCourse3.2Stageseparation(多級分離)

Aprocessinwhichthefeedisseparatedintovaporandliquidphasesbytwoormoreequilibriumflashesatconsecutivelylowerpressures.

在脫氣過程中，分幾次降低壓力，每次降壓所分離出的氣體都及時地從油氣體系中放出，直至降至最后的指定壓力1)Moreoilisobtained.Theoilcontainsalargeamountoflighteroilcomponents.Thegashasasmallerspecificgravity.2)Thecompositionofthesystemischanged.ProvincialBilingualTeachingDemonstrationCourseTwo-stageseparationThree-stageseparationProvincialBilingualTeachingDe