• / 10
  • 下载费用:5 下载币  

1-s2.0-S1876380414600434-main

关 键 词:
s2 S1876380414600434 main
资源描述:
RESEARCHPAPERPETROLEUMEXPLORATIONANDDEVELOPMENTVolume41,Issue3,June2014OnlineEnglisheditionoftheChineselanguagejournalCitethisarticleas:PETROL.EXPLOR.DEVELOP.,2014,41(3):377–386.Receiveddate:14Nov.2013;Reviseddate:23Apr.2014.*Correspondingauthor.E-mail:yzx@PetroChina.com.cnCopyright©2014,ResearchInstituteofPetroleumExplorationandDevelopment,PetroChina.PublishedbyElsevierBV.Allrightsreserved.Anewapproachtoestimatingrecoveryfactorforextra-lowpermeabilitywater-floodingsandstonereservoirsYUANZixue1,*,WANGJingyun2,LIShuxun1,RENJihong1,ZHOUMingqing11.PetroChinaResearchInstituteofPetroleumExploration2.PetroChinaExploration&ProductionCompany,Beijing100007,ChinaAbstract:ThemethodsofestimatingrecoveryfactorofnewlyaddedmeasuredreservesinexistingpetroleumreservesstandardizationofChinaareunsuitableforsandstoneoilreservoirsofextra-lowpermeabilitywithwaterflooding,sonewempiricalformulamethodandanalogousmethodforestimatingrecoveryfactorofthereservoirsarestudied.Thekeyparametersinfluencingrecoveryfactorareperme-ability,formationoilviscosity,porosity,mobilityandwellspacingdensity.Basedontherequirementssuchaslongerdevelopmenttime,reliablereservesandavailablereservoirparameters,37sandstoneoilreservoirsofextra-lowpermeabilitywereselected,and19recoveryfactormodelsweresummarized.Withconsiderationofhighmultipleregressioncoefficientandlowstandarderror,4empiricalformulaesuitableforreservoirofwater-flooddevelopmentwithverticalwellwereestablished.ComparisonofcalculatedresultsfromtheempiricalformulaeandcalibratedrecoveryfactorsofPetroChinarecentlyshowsthattheformulaematchwell.Itisimportanttochoosereservoirwithsuccessfulpilotsand/ordevelopedinlargescaleasbenchmarkreservoirsintheanalogyestimation.Basedontheprincipleofkeep-ingconsistentofanalogousmethodwithproductionperformance,apracticalexampleofChang8reservoir,Triassic,FXoilfieldwasgiventoillustratethedeterminationofrecoveryfactorofextra-lowpermeabilityreservoir.Empiricalformulamethodandanalogousmethodhavetheiradvantagesanddisadvantages,reservesestimatorsshouldpaygreatattentiontothereliabilityofdata,toapplicationconditionforempiricalformulamethodandtotheavoidanceofsinglereservoirsinanalogousmethod.Keywords:extra-lowpermeability;sandstonereservoir;waterflooddevelopment;recoveryfactorcalibration;empiricalformulamethod;analogousmethod;measuredreserves;provedreservesIntroductionSince2000,thedevelopmenttechnologiesforlowpermea-bilitysandstonereservoirshavebeenimprovedcontinuously,especiallyunder-balanceddrilling,advancedwaterinjectionandmassivehydraulicfracturinghavebeensuccessfullyappliedtopromotethesinglewellproductionandeconomicbenefits,makedifficultproducingoiloriginalinplaceinextra-lowpermeabilityreservoirsrecoverable,resultinginthesubstantialincreaseofprovedreservesinlowpermeabilityreservoirsfrom35%to70%ofthetotalprovedreservesan-nually.InChina’sexistingreservesstandard,methodsofcalibratingrecoveryfactorinnewaddedreservesaremainlysuitableforsandstonereservoirswithmiddleandhighper-meability,therelackmethodsofcalibratingrecoveryfactorforlowpermeabilityreservoirs,especiallyforextra-lowpermeabilityreservoirs.Inviewofthisissue,thispapermakesstatisticsonextra-lowpermeabilityblockswithahighdegreeofdevelopment,analyzesthefactorsaffectingtherecoveryfactor,establishesempiricalformulaetocalculaterecoveryfactor;meanwhilestudiestheanalogousmethodtodeterminetherecoveryfactorofextra-lowpermeabilityreservoirs,pro-posestheanalogouskeyparametersandanalyticaltechniquesforthiskindofreservoir.Finally,basedonthecharacteristicsofextra-lowpermeabilityreservoirs,thepaperanalyzestheadvantagesanddisadvantagesofthetwomethodsandthekeyproblemsthatshouldbepaidattentiontoinapplication.1Theextra-lowpermeabilitysandstonereservoirsandexistingproblemsinrecoveryfactorcalibration1.1ReservoiranddistributionExtra-lowpermeabilitysandstonereservoirsrefertothereservoirswhichhaveanairpermeabilityof(1−10)×10−3μm2,nooilflowingoutaftercommonformationtestingundernaturalconditions,andrequiremassivehydraulicfracturingandwaterinjectiontoputintoproduction.Thefluidflowinthiskindofreservoirdoesn’tfollowtheDarcy’slaw,andcrudeoilflowneedstoovercomethestartingpressuregra-dient.Mostofthesereservoirsarelithologic,attheburieddepthof2000m−3000m.Poorinphysicalproperties,thesereservoirsgenerallyhavehighproductionafterfracturingandYUANZixueetal./PetroleumExplorationandDevelopment,2014,41(3):377–386−378−rapidproductiondeclineintheinitialstage,andinlatestagelowproductionandslowdecline,generallythestablepro-ductionis1−2t/dafter1−6monthsonproduction.Thecrudeoilisfairlygoodinquality,belongingtomediumandlightoil,withasurfacedensityof0.845g/cm3to0.871g/cm3,andasurfaceviscosityof2.5−20mPa⋅s.ProvedOOIPofextralowpermeabilitysandstonereservoirsfoundbyPetroChinaCom-panyLimited(hereinafterreferredtoasPetroChina)mainlydistributesinCretaceousFuyuandYangdachengzireservoirsinDaqingandJilinareaofSongliaobasin,TriassicChang6andChang8reservoirsinChangqingareaofOrdosBasin[1−2].1.2ReservesincreasingandproducingstatusSincethelateperiodofthe1990s,PetroChinahavemadesuccessesindevelopingextra-lowpermeabilityreservoirswithmassivehydraulicfracturingandadvancedwaterinjec-tion,raisingsinglewelldailyoilproduction,andreservesofextralowpermeabilityoilreservoirgreatly,andpartoftheannualnewlyaddedprovedOOIPwasputintodevelopmenteachyear.Since2008,OOIPoflowpermeabilityreservoirs(airpermeabilityoflessthan50×10−3μm2)hasincreasedto70%oftheadditionalprovedOOIPeachyear.Inlowperme-abilityOOIP,ultralowpermeability(airpermeabilityoflessthan1×10−3μm2)OOIPaccountforthelargestproportion,fol-lowedbyOOIPofextralowpermeability[3].Bytheendof2012,provedreservesofextralowperme-abilitysandstoneoilreservoirsdevelopedbyPetroChinaac-countforapproximately60%ofthetotalprovedreservesofthiskindofreservoir,witharecoveryfactorof5%−35%,mainly15%−25%,andonaverage20.5%.Since2012,Chang-qingandJilinoilfieldhavesetuphorizontalwelldevelopmentpilotsofreservoirsofultralowpermeability(orcalledtightoilreservoir),wheregreatprogresshasmadeindrillingandfracturingtechnology,waterinjectionisbeingstudied[4−5].1.3MethodandexistingproblemsincurrentrecoveryfactorcalibrationIntheexistingpetroleumindustrystandardofChina“thecalculationmethodsofoilrecoverablereserves”(SY/T5367-2010)[6],therearecompletemethodsforreservecali-brationofwaterfloodingsandstonereservoirswithmediumandhighpermeabilityinearlydevelopment,butthereisnoempiricalformulasuitableforextralowpermeabilitysand-stonereservoirs.Thereare3empiricalformulaeforcalculat-ingrecoveryfactorofsandstonereservoirswithwaterflood-inginthisstandard[6]:RR0.2740.1116lg0.09746lgEKµ=−+−fkR0.018020.067410.0001675hSVT−+(1)Roi0.058420.08461lg(/)EKµ=++0.34640.003871fφ+(2)Table1RelationshipbetweenwellspacingdensityandrecoveryfactorfordifferenttypesofreservoirsTypeNumberofunitsMobility/(10−3μm2⋅(mPa⋅s)−1)EmpiricalformulaeI13300-600f2.012R0.6031eSE−=II27100-300f2.354R0.5508eSE−=III6730-100f2.635R0.5227eSE=IV195-30f5.423R0.4832eSE=V18<5f10.148R0.4015eSE−=EmpiricalFormula(3)isshowninTable1Accordingtostatisticsof25waterfloodingsandstoneres-ervoirs,Formula(1)wasestablishedbyYuQitaietal.Expertsin1996,whichissuitableforreservoirswithanairpermeabil-ityof(69-3000)×10−3μm2.Accordingtostatisticsof150wa-terfloodingsandstonereservoirs,Formula(2)wasestablishedbyLiuYufenandotherexpertsinthe1994,whichissuitableforreservoirswithanairpermeabilityof(4.8−8900)×10−3μm2.Accordingtostatisticsof144developmentunits,For-mula(3)wasestablishedbyZhangSufangandotherexpertsinthe1989.Itisworthnotingthat,inthestatisticdataofFormula(2),thereisonly1extralow-permeabilityunitwiththeairpermeabilityoflessthan10×10−3μm2,thereare6lowpermeabilityunitswiththeairpermeabilityof(10-50)×10−3μm2,accountingfor4.7%ofthetotalunits[7];InbasicdataofFormula(1),thenumberoflowpermeabilityreservoirsisnotavailable,theempiricalFormula(3)wassetupbasedonthemobilityinterval,thenumberofextralowpermeabilityunitsisnotavailabletoo.Intheory,thethreeempiricalformulaearenotapplicableforrecoveryfactorcalibrationofwaterflood-ingsandstonereservoirswithextralowpermeability,themainreasonsare:notonlybefore2000waterfloodingsandstonereservoirswithextralowpermeabilityhavesmallscalefrac-turingandtherewerelimitednumberofdevelopedreservoirsforstatisticsofextralowpermeabilityreservoirs;butmoreimportantly,extralowpermeabilityreservoirsdifferwidelyfromthemiddleandhighpermeabilitysandstonereservoirsinflowmechanismanddevelopmenttechnology(thelatterbasicwithoutfracturing,theformerneedmassivefracturing)(theformerdoesnotobeytheDarcy’slaw,thelatterdoes)[8].Tak-ingempiricalFormula(2)forwaterfloodingsandstoneinthepetroleumindustrystandardasanexample,thecalculatedrecoveryfactorofextralowpermeabilityunitsis5.1%−8.2%lowerthanthecalibratedone(Table2),whilethecalculatedrecoveryfactorofmediumpermeabilityunitsinDa27Blockisclosetothecalibratedone,showingthattheexistingem-piricalformulaeforcalibratingrecoveryfactorofwaterfloodingsandstonereservoirsaremoreapplicableformediumandhighpermeabilityreservoirs.Fornewreservoirsinamatureoilfieldorsimilarnewoil-fieldsadjacenttomaturefields,analogousmethodcanbetakentopredictandcalibraterecoverablereserves.Forextralowpermeabilitysandstonereservoirs,becauseofpoorphysicalproperties,lowproductionofwells,andlowannualYUANZixueetal./PetroleumExplorationandDevelopment,2014,41(3):377–386−379−Table2ComparisonofrecoveryfactorcalculatedbyFormula(2)andcalibratedrecoveryfactorforwaterfloodingsandstonereservoirsOil-fieldBlockForma-tionReservoirReservoirtypeCalibrationtime(year-month)Airper-meability/10−3μm2Formationoilviscosity/(mPa·s)Poro-sity/%Wellspacingdensity/(well·km−2)RecoveryofOOIP/%Calculatedrecoveryfactor/%Calibratedrecoveryfactor/%Da’anDa208Quan3-4memberFuyu,yangda-chengziUltralowpermeability2010-120.44.1010.519.259.18.416.2Da’anDa26Yao1memberPutaohuaExtralowpermeability2012-115.24.1016.79.199.916.121.2HaituoziHai24Yao2-3memberSaertuExtralowpermeability2010-124.516.7015.412.9712.011.419.6Da’anDa27Nen3memberHeidi-miaoMiddlepermeability2010-12187.07.1923.115.0020.032.831.8oilrecoveryrate(generally0.3%−0.6%),currentlytherecov-eryofOOIPisverylow,mostlylessthan10%,resultinginthelackofanalogousreservoirswithreliablerecoveryfactorinsomeregions,andthusthelowprecisionofcalibratedrecov-eryfactor.2KeyparametersinfluencingrecoveryfactorFactorsaffectingrecoveryfactorofoilreservoirsmainlyincludereservoirphysicalproperties,fluidpropertiesandde-velopmentmodeetc.Forwaterfloodingsandstonereservoirswithextralowpermeability,twomainparameterscharac-terizingreservoirphysicalpropertiesarepermeabilityandporosity;amainparametercharacterizingfluidpropertiesisformationoilviscosity,whichreflectsformationtemperature,gas-oilratioandsurfaceoildensityetccomprehensively;amainparametercharacterizingfluidflowpropertiesinporousmediaisoilmobility;amainparameterindicatingeffectofwaterinjectiondevelopmentiswellspacingdensity,smallerwelldistancebetweeninjectorandproducercanimproveoildisplacementefficiencyandvolumetricsweepefficiency,thusincreaseproductionandrecoveryfactor.Basedonstatisticsof37extralowpermeabilityreservoirs,recoveryfactoriscorre-latedwithpermeabilityandmobilityclosely,followedbywellspacingdensityandporosity,andpoorlycorrelatedwithfor-mationoilviscosity(Fig.1).ItcanbeseenfromFig.1,thecorrelationbetweenforma-tionoilviscosityandrecoveryfactorispoorerthanthatbe-tweenpermeabilityandrecoveryfactor,contradictingwiththecommonideathatthecorrelationbetweenformationoilvis-cosityandrecoveryfactorisstrong.Analysisshowsthattwomainreasonsarebehindthis:(1)Thereisacorrelationbe-tweenformationoilviscosityandpermeability.IllustratedbyFig.2,mostoilreservoirsfollowthepatternbelow:thesmallertheformationoilviscosityis,thelowerthepermeabil-ityis,conversely,thehighertheformationoilviscosityis,thehigherthepermeabilityis,andthewiderrangeofpermeabilityis,thatistosay,permeabilityandformationoilviscosityarepositivelycorrelated.Buttherelationshipofthemwithrecov-eryfactorisexactlyoppositetothis.Thatistosay,asperme-abilityincreases,recoveryfactorgoesup;asoilviscosityFig.1Relationshipbetweenrecoveryfactorandpermeability,porosity,formationoilviscosity,wellspacingdensity,andoilmobilityincreases,recoveryfactorgoesdown.Itisfoundbyanalysisthatrecoveryfactorshouldreducewiththeincreaseofoilviscosity,butinfactrecoveryfactorrisesbecausepermeabil-ityincreases,whichcounteractstheeffectofoilviscosityin-creaseonrecoveryfactor(Fig.1c).(2)Reservoirphysicalpropertieshavedifferentdistributionfromformationoilprop-erties.SandstonereservoirsinChinaaremostlycontinentaldeposits,withwiderrangeofairpermeabilityandstronghet-erogeneity;incontrasttopermeabilitydistribution,oilproper-tieshavenolargechange,formationoilviscosityisnarrowinrange.Forexample,airpermeabilityofmiddleandhighper-meabilityreservoirsinDaqingplacanticlineoilfieldofChinais50−800×10−3μm2,formationoilviscosityis3−12mPa⋅s;whereasairpermeabilityofFuyangreservoirwithlowper-meabilityintheoutskirtsofDaqingplacanticlineoilfieldis(0.4−36.7)×10−3μm2,formationoilviscosityis4−10mPa⋅s.InOrdosBasin,centralnorthofChina,reservoirsfromChang8ofTriassicYanchangFormationuptoJurassicYananYUANZixueetal./PetroleumExplorationandDevelopment,2014,41(3):377–386−380−Fig.2RelationshipofpermeabilityandformationoilviscosityFormationhaveawideairpermeabilityof(0.1−500.0)×10−3μm2,mainpermeabilityislessthan50×10−3μm2,andforma-tionoilviscosityof0.93−11.91mPa⋅s.Inthesameoilfieldorreservoir,permeabilityrangeismuchwiderthanformationoilviscosityrange.Forexample,airpermeabilityofFuyangres-ervoirinDong162block,Yushulinoilfield,Daqingareais(0.1−36.7)×10−3μm2,formationoilviscositybasicallyiscon-stantat3.9mPa⋅s[9].PermeabilityofChang8reservoirofYanchangFormationinBaimablockofXifengoilfieldofChangqingareais(0.1−56.9)×10−3μm2,formationoilviscos-ityis1.33−1.67mPa⋅swithlittlechange[10].Inconclusion,thedifferenceinrecoveryfactorbetweendifferentblocksinthesamereservoirofcertainoilfieldisattributedtopermeabilityvariation,whileoilviscosityhaslittleimpactonrecoveryfactor.Butfordifferentoilfields,oftheeffectofoilviscosityonrecoveryfactorincreasestosomeextent,underthesamepermeability,oilviscositywillbethekeyparameterinfluenc-ingrecoveryfactor.Forinstance,FuyangreservoirinToutaioilfieldofDaqingarea[11]andChang8reservoirofYanchangFormationinXifengoilfieldofchangqingarea[10],aresimilarinairpermeability,theformer1.19×10−3μm2,thelatter1.02×10−3μm2,respectively,howevertheirformationoilvis-cosityis4.2mPa⋅sand1.5mPa⋅s,respectively,Fuyangreser-voir,higherinoilviscosity,ispoorerindevelopmenteffec-tivenessandlowerinrecoveryfactor(around15%),incon-trast,Chang8reservoirofXifengoilfieldshowgooddevel-opmentresults,andhigherrecoveryfactorofaround20%.3Empiricalformulamethod3.1SelectionofbasicdataBasicdatausedinestablishingempiricalformulacamefromDaqing,JilinandChangqingarea.DatastatisticunitisdevelopingunitinChinapetroleumindustry,whichmeansthatonereservoirorpackageofseveralreservoirsformonedevelopingtargetzoneinverticaldirection,oneblockorpackageofseveralblocksformonedevelopingblockinoneoilfieldinplane,oneunitrequireonedevelopmentwellpat-terntoproduceindevelopmentprogram.Accordingtothecharacteristicsofsandstonereservoirswithextralowperm
展开阅读全文
  石油文库所有资源均是用户自行上传分享,仅供网友学习交流,未经上传用户书面授权,请勿作他用。
0条评论

还可以输入200字符

暂无评论,赶快抢占沙发吧。

关于本文
本文标题:1-s2.0-S1876380414600434-main
链接地址:http://www.oilwenku.com/p-70324.html

当前资源信息

吾王的呆毛

编号: 20180607204836063571

类型: 共享资源

格式: PDF

大小: 558.09KB

上传时间: 2018-06-08

广告招租-6
关于我们 - 网站声明 - 网站地图 - 资源地图 - 友情链接 - 网站客服客服 - 联系我们
copyright@ 2016-2020 石油文库网站版权所有
经营许可证编号:川B2-20120048,ICP备案号:蜀ICP备11026253号-10号
收起
展开