基于应力敏感的致密油藏孔隙结构及油水两相渗流特征  

Pore Structure and Oil-Water Two-Phase Seepage Characteristics of Tight Oil Reservoirs Based on Stress Sensitivity

作　　者：王长权[1] 田中敬[2] 王晨晨 陈亮[4] 王国庆 Wang Changquan;Tian Zhongjing;Wang Chenchen;Chen Liang;Wang Guoqing(Hubei Key Laboratory of Oil and Gas Drilling and Production Engineering,Yangtze University,Wuhan,Hubei 430100,China;China National Petroleum Jidong Oilfield Branch,Tangshan,Hebei 063000,China;Cooperative Innovation Center of Unconventional Oil and Gas,Yangtze University University,Wuhan,Hubei 430100,China;China Petroleum Xinjiang Oilfield Branch,Karamay,Xinjiang 834000,China)

机构地区：[1]长江大学油气钻采工程湖北省重点实验室,湖北武汉430100 [2]中国石油冀东油田分公司,河北唐山063000 [3]长江大学非常规油气湖北省协同创新中心,湖北武汉430100 [4]中国石油新疆油田分公司,新疆克拉玛依834000

出　　处：《特种油气藏》2023年第4期131-138,共8页Special Oil & Gas Reservoirs

基　　金：国家科技重大专项“低渗-致密砂岩储层体系表征及评价新方法”(2017ZX05009001—002);中国石油重点开发项目“低渗透油藏效益开发专项工程研究”(KF2018A05)。

摘　　要：针对致密油藏应力敏感性强引起流体渗流能力变差和产能降低的问题,选取冀东油田某致密储层岩心进行全直径岩心驱替实验和原位CT扫描实验,研究应力敏感作用下的致密油藏孔隙结构及油水两相渗流特征。研究表明:随净应力的增加,应力敏感性增强,岩心的喉道和较大孔隙受到压缩而发生变形,部分超微细小孔隙甚至闭合,油相相对渗透率下降速度和水相相对渗透率上升速度均增大,两相渗透率曲线逐渐下移;束缚水饱和度和残余油饱和度均增大,共渗点右移,两相渗流区逐渐变小,水驱油效率降低,说明油井见水后,含水率大幅增加,油水同产期较短,水驱突破快,水驱油效率下降,主要依靠补充地层能量降低应力敏感对油水两相渗流规律及采收率的影响。研究成果对致密油藏开发技术方案的制订具有重要指导意义。To address the problem of poor fluid permeability and reduced production capacity caused by strong stress sensitivity in tight reservoirs,a core from a tight reservoir in the Jidong Oilfield was selected for full-diameter core displacement experiments and in situ CT scanning experiments to study the pore structure and oil-water two-phase permeability characteristics of tight reservoirs under the stress sensitivity.The study shows that with the increase of net stress,the stress sensitivity increased,the throat and larger pores in the core were compressed and deformed,some of the ultra-fine pores were even closed,the falling speed of the relative permeability of the oil phase and the rising speed of the relative permeability of the water phase increased,and the two-phase permeability curve gradually shifted down;the saturation of irreducible water and residual oil increased,the co-permeability point shifted to the right,the two-phase permeability zone gradually became smaller,and the efficiency of water-oil displacement decreased;it indicated that after water breakthrough in the oil well,the water cut increased significantly,the oil-water production period was shorter,the breakthrough of water displacement was rapid,and the efficiency of water-oil displacement decreased.The impact of stress sensitivity on oil-water two-phase seepage law and recovery factor was mainly reduced by supplementing formation energy.The study results have important guidance significance for the development of technical solutions for tight reservoir development.

关 键 词：致密油藏 应力敏感 孔隙结构 油水两相渗流 相对渗透率 驱油效率 冀东油田 

分 类 号：TE357[石油与天然气工程—油气田开发工程]