CO_(2)混相压裂液对低渗透储层岩心的微观作用机理  

Microscopic Mechanism of CO_(2) Miscible Fracturing Fluid on Low Permeability Reservoir Rocks

作　　者：李迎辉 王长权 王启夏 LI Yinghui;WANG Changquan;WANG Qixia(Jidong Oilfield Branch Company,PetroChina,Tangshan,Hebei 063200,P R of China;Hubei Key Laboratory of Drilling and Production Engineering for Oil and Gas,Yangtze University,Wuhan,Hubei 430100,P R of China)

机构地区：[1]中国石油冀东油田分公司,河北唐山063200 [2]油气钻采工程湖北省重点实验室(长江大学),湖北武汉430100

出　　处：《油田化学》2022年第2期306-310,323,共6页Oilfield Chemistry

基　　金：国家自然科学基金“高温高压CO_(2)-原油-地层水三相相平衡溶解度规律”(项目编号51404037),国家重大科技专项“渤海湾盆地黄骅坳陷滩海开发技术示范工程”(项目编号2011ZX05050)。

摘　　要：为明确CO_(2)混相压裂液与储层岩心的作用机理,以柳赞断块储层岩心为实例,利用岩心驱替、SEM、XRD和CT等实验方法开展CO_(2)混相压裂液体系中不返排酸、CO_(2)+增溶剂(或缩膨剂或降黏剂)在地层压力和地层温度下与岩心相互作用前后岩心孔隙结构、岩心矿物成分及渗透率的变化规律实验。研究表明:不返排酸和CO_(2)与不同水溶性添加剂混合形成碳酸溶液均具有溶蚀长石和黏土矿物的作用,且优先溶蚀长石,溶蚀后可生成高岭石和石英等矿物,其中不返排酸的溶蚀作用最强,其次是CO_(2)与增溶剂混合液、CO_(2)与降黏剂混合液;CO_(2)混相压裂液注入前后液测渗透率与气测渗透率呈相同的增大趋势,且液测渗透率增大幅度随气测渗透率的变化关系表现为很强的乘幂关系。该研究成果对CO_(2)混相压裂提高采收率技术提供一定的技术支持。The interaction mechanism between CO_(2) miscible fracturing fluid and reservoir core was clarified through the experiment of the change law of core pore structure,core mineral composition and permeability before and after the interaction of non flowback acid,CO_(2)+solubilizer(or swelling agent or viscosity reducer)in CO_(2) miscible fracturing fluid system with the core of Liuzan fault block under formation pressure and formation temperature by using the experimental methods such as core displacement,SEM,XRD and CT.The results showed that non flowback acid and the carbonic acid solution formed by the mixing of CO_(2) and different water-soluble additives could dissolve feldspar and clay minerals and preferentially dissolve feldspar to produce minerals such as kaolinite and quartz.The dissolution effect of non flowback acid was the strongest,followed by the mixture of CO_(2) and solubilizer and the mixture of CO_(2) and viscosity reducer.The liquid permeability and gas permeability showed the same increasing trend,and the increasing range of liquid permeability showed a strong power relationship with the change of gas permeability before and after CO_(2) miscible fracturing fluid injection.The research results provided some technical support for CO_(2) miscible fracturing EOR technology.

关 键 词：混相压裂 低渗透 相互作用 孔隙结构 岩心成分 

分 类 号：TE357.12[石油与天然气工程—油气田开发工程]