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1、研究論文(Articles)科技導(dǎo)報2011,29(01)特低滲透儲層滲流特征和影響因素1,21,23何文祥,馬清,馬超亞1.長江大學(xué)地球化學(xué)系,湖北荊州4340232.長江大學(xué)油氣資源與勘探技術(shù)教育部重點實驗室,湖北荊州4340233.中國石油天然氣股份有限公司長慶油田分公司第七采油廠,陜西吳旗717606摘要為了研究特低滲透儲層滲流特征及影響因素,以鄂爾多斯盆地白豹油田為例,對特低滲透巖心的單相和兩相滲流特征進行分析。結(jié)果表明,特低滲巖心單相滲流具有擬啟動壓力梯度,滲透率越小,擬啟動壓力梯度越大;其滲流曲線不再為一條直線,而為下凹型曲線,呈現(xiàn)非達西滲流特征;其流變曲線不是直
2、線,而為上凸型曲線,流體為非牛頓假塑性流體,在較小外力作用下不發(fā)生流動,只產(chǎn)生彈性變形,只有當(dāng)外力大于某值時,流體才發(fā)生流動,且具有明顯的屈服應(yīng)力;動極限剪切應(yīng)力與滲透率的關(guān)系表明,動極限剪切應(yīng)力隨滲透率減小而急劇增大;隨著剪切速率的增大,視黏度逐漸降低,在剪切作用之后,流體濃度具有變小的特性;油水兩相滲流曲線說明束縛水飽和度和殘余油飽和度偏高,共滲區(qū)較窄,且隨著含水飽和度增大,油相滲透率快速下降,水相滲透率緩慢增長。巖心的滲透率大小、潤濕性、水鎖等因素均對滲流特征有影響。關(guān)鍵詞特低滲透儲層;啟動壓力梯度;單相滲流;非達西滲流中圖分類號TE348文獻標(biāo)識碼Adoi10.3981
3、/j.issn.1000-7857.2011.01.03SeepageCharacteristicsandInfluencingFactorsinUltra-lowPermeabilityReservoirs1,21,23HEWenxiang,MAQing,MAChaoya1.DepartmentofGeochemistry,YangtzeUniversity,Jingzhou434023,HubeiProvince,China2.KeyLaboratoryofExplorationTechnologiesforOilandGasResources,MinistryofEduc
4、ation;YangtzeUniversity,Jingzhou434023,HubeiProvince,China3.No.7ProductionPlant,ChangqingOilFieldCompany,ChinaNationalPetroleumCorporation,Wuqi717606,ShaanxiProvince,ChinaAbstractInordertostudyseepagecharacteristicsandinfluencingfactorsinultra-lowpermeabilityreservoirs,withsamplestakenfromOr
5、dos,experimentsofsinglephaseflowandoil-waterphaseflowwereconducted.Theresultsindicatethereexistsathresholdpressuregradientforsinglephaseflowsforpartofsamples.Theflowisofnon-darcyseepagewhenthepressuregradientislowanditchangesintodarcyflowathighpressure;butforothersamples,noobviousnon-darcyfl
6、owisfound.Thelowerthecorepermeabilityis,thehigherthepressureunderwhichnon-Darcystatewillretainandlesstheflowvolumewillbe.Theflowcurveforthecoreisnotastraightlinebutacurveprotrudingtotheshearingstressaxis.Thefluidisnon-Newtonianandfakeplasticfluid,whichdoesnotmovebesidessomeelasticdeformation
7、underaweakexternalforce,andwhichmovesunderastrongexternalforce,withanobviousyieldstress.Therelationbetweenmovingshearingstressandpermeabilityindicatesthattheshearingstressdecreasesrapidlywiththedecreaseofpermeability.Theapparentviscosityreducesslow