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1、研究论文（Articles）科技导报2011，29（01）特低渗透储层渗流特征和影响因素1，21，23何文祥，马清，马超亚1.长江大学地球化学系，湖北荆州4340232.长江大学油气资源与勘探技术教育部重点实验室，湖北荆州4340233.中国石油天然气股份有限公司长庆油田分公司第七采油厂，陕西吴旗717606摘要为了研究特低渗透储层渗流特征及影响因素，以鄂尔多斯盆地白豹油田为例，对特低渗透岩心的单相和两相渗流特征进行分析。结果表明，特低渗岩心单相渗流具有拟启动压力梯度，渗透率越小，拟启动压力梯度越大；其渗流曲线不再为一条直线，而为下凹型曲线，呈现非达西渗流特征；其流变曲线不是直
2、线，而为上凸型曲线，流体为非牛顿假塑性流体，在较小外力作用下不发生流动，只产生弹性变形，只有当外力大于某值时，流体才发生流动，且具有明显的屈服应力；动极限剪切应力与渗透率的关系表明，动极限剪切应力随渗透率减小而急剧增大；随着剪切速率的增大，视黏度逐渐降低，在剪切作用之后，流体浓度具有变小的特性；油水两相渗流曲线说明束缚水饱和度和残余油饱和度偏高，共渗区较窄，且随着含水饱和度增大，油相渗透率快速下降，水相渗透率缓慢增长。岩心的渗透率大小、润湿性、水锁等因素均对渗流特征有影响。关键词特低渗透储层；启动压力梯度；单相渗流；非达西渗流中图分类号TE348文献标识码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
