致密砂岩油藏裂缝与基质间渗吸特征及主控因素  

Dynamic imbibition characteristics between fractures and matrix in tight sandstone reservoirs and main controlling factors

作　　者：林魂 宋西翔 罗超 孙新毅 杨兵 董利飞 LIN Hun;SONG Xixiang;LUO Chao;SUN Xinyi;YANG Bing;DONG Lifei(Chongqing University of Science&Technology,Chongqing City,401331,China;Chongqing Three Gorges University,Chongqing City,404130,China)

机构地区：[1]重庆科技学院,重庆401331 [2]重庆三峡学院,重庆404130

出　　处：《油气地质与采收率》2022年第5期133-140,共8页Petroleum Geology and Recovery Efficiency

基　　金：重庆市自然科学基金面上项目“考虑化学渗透压的页岩储层压裂液渗吸机理与模型研究”(cstc2019jcyj-msxmX0457);重庆市教委科学技术研究项目“页岩气压裂液返排控制机理与环保处理技术研究”(KJQN202101516)。

摘　　要：为提高致密砂岩油藏水驱基质动用程度,以鄂尔多斯盆地A83区块长8储层为研究对象,建立了基于核磁共振在线扫描的岩心水驱渗吸实验,研究了裂缝性致密砂岩储层水驱开发中基质的动用特征,从孔隙尺度定量评价了3类孔隙的采出程度,并对影响渗吸效率的4个因素进行了分析。结果表明,水驱动态渗吸过程可以划分为3个阶段:驱替作用下大孔隙采出程度快速增加、渗吸作用下微小孔隙采出程度缓慢增加、动态渗吸达到平衡。渗吸过程中微小孔隙动用程度最大,对总采出程度的贡献率最高,中孔隙作为连接微小孔隙和大孔隙的流动通道,动用程度最小。整个动态渗吸过程就如同一个有机体,想要最大程度提高总采出程度,就必须控制好驱替速度(0.1 mL/min)、表面活性剂质量分数(0.05%)和焖井时间(占总时间75%),最大程度地发挥渗吸和驱替2种采油方式的作用,确保在提高微小孔隙采出程度的同时也尽可能地增大大孔隙的采出程度。Taking Chang8 reservoir in A83 area of Ordos Basin as the research object,a core displacement experiment based on the online scanning of nuclear magnetic resonance(NMR)was performed to explore the method of enhanced oil re⁃covery(EOR)in tight sandstone reservoirs and solve the problem of low production of matrix during water flooding.Specifi⁃cally,the process of dynamic imbibition between fractures and matrix in water flooding was simulated;the recovery of three types of pores was quantitatively evaluated regarding pore scale,and four factors affecting imbibition efficiency were ana⁃lyzed.The results show that the process of dynamic imbibition of water flooding can be divided into three stages,i.e.,the stage of a rapid rise of recovery of the macropores under the displacement effect,the stage of a slow rise of recovery of the micropores under the imbibition effect,and the stage of basically reaching dynamic imbibition balance.In the process of im⁃bibition,the recovery of micropores registers the largest,which is the main contributor to total recovery,and the recovery of the mesopores,flow channels connecting the micropores and the macropores,registers the smallest.To sum up,the whole process of dynamic imbibition is like an organism.For the maximization of the total recovery rate,it is necessary to control the injection rate(0.1 mL/min),surfactant concentration(0.05%),and soaking time(accounting for 75%of the total).In ad⁃dition,we should make the best use of the two oil recovery methods of the imbibition and displacement to ensure that the re⁃covery of the micropores and macropores is increased as much as possible.

关 键 词：致密砂岩 动态渗吸 核磁共振 微观孔隙 渗吸效率 鄂尔多斯盆地 

分 类 号：TE312[石油与天然气工程—油气田开发工程]