杏子川地区长6储层压裂液原位置换原油  

In-Situ Displacement of Crude Oil by Fracturing Fluid in Chang-6 Reservoir in Xingzichuan

作　　者：柏浩 周福建 吴俊霖 丁志远 杨飒飒 盛连奇 姚二冬 BAI Hao;ZHOU Fujian;WU Junlin;DING Zhiyuan;YANG SaSa;SHENG Lianqi;YAO Erdong(National Key Laboratory of Petroleum Resources and Engineering,China University of Petroleum,Beijing 102249)

机构地区：[1]中国石油大学(北京)油气资源与探测国家重点实验室,北京102249

出　　处：《钻井液与完井液》2024年第3期396-404,共9页Drilling Fluid & Completion Fluid

基　　金：国家自然科学基金“纳米乳液在致密砂岩储层中的吸附特性及其解水锁机制研究”(52004306);中国石油天然气集团有限公司-中国石油大学(北京)战略合作科技专项“鄂尔多斯盆地致密油-页岩油富集、高效开发理论与关键技术研究”(ZLZX2020-02)。

摘　　要：杏子川地区延长组长6储层具有含油饱和度低、油湿性强,非均质性强(渗透率为0.10~1.0 mD)等特征。常规压裂液体系润湿改性能力弱、渗吸置换效果差,亟需研究具有渗吸提采功能的压裂液。借助了核磁共振T_(2)谱手段,测试了不同组成和配比的化学剂对长6储层岩心内微-纳孔径原油的动用能力,并探究了压裂液原位置换原油的影响因素及其渗吸机理。结果表明:带负电的阴离子试剂AX-2更适合动用长6低含油饱和度储层,0.10%AX-2渗吸采收率大于30%,纳米小孔与微米大孔动用程度分别为42.08%与22.62%;将表面活性剂AX-2复配成为10 nm尺寸的纳米乳液AX-1,抗吸附能力更强,动用效果更佳,纳米孔与微米孔动用程度可提升至58.26%与29.70%;界面张力为1.5 mN/m时AX-1最适合动用长6储层原油,此时液体具有较高的渗吸动力与原油剥离能力。优选体系复配后现场压裂稳定,试油效果良好,平均日产油量超过26 t。The Chang-6 reservoir in the Yanchang formation in Xingzichuan area is characteristic of low oil saturation,strong oil wetting and strong heterogeneity(permeability=0.10–1.0 mD).In fracturing operations in this area,it was found that the conventional fracturing fluids have weak wettability alteration ability and poor imbibition displacement effect.To efficiently develop this reservoir,it is imperative to use a fracturing fluid with the ability of production enhancement by imbibition.Using NMR T_(2) spectrum,chemicals of different compositions were tested for their ability to produce the crude oils stored in the micrometer-nanometer sized pores in the Chang-6 reservoir,and the factors affecting fracturing fluids’in-situ displacement of crude oil as well as the imbibition mechanism of the in-situ displacement are investigated.The results of the study show that compared with other agents,AX-2,a negatively charged ionic surfactant agent,is more suitable for producing the low oil saturation Chang-6 reservoir.Using 0.10%of AX-2,the imbibition recovery of oil is greater than 30%,and the percent oil produced from the small nanometer-sized pores is 42.08%,while that from the large micrometer-sized pores is 22.62%.If AX-2 is used to formulate a 10-nanometer nanoemulsion AX-1,it has stronger anti-adsorption ability and better performance in producing the oil from the Chang-6 reservoir;the percent oil produced from the nanometer pores is increased to 58.26%,while that from the micrometer pores is increased to 29.7%.An AX-1 emulsion with surface tension of 1.5 mN/m is the best emulsion for producing the Chang-6 reservoir,since this emulsion has higher imbibition force and crude oil stripping capacity.The fracturing fluid optimized with the AX-1 emulsion is used in field fracturing operations,and good results were obtained,the average daily production rate of crude oil reached 26 tons.

关 键 词：低含油饱和度 纳米乳液 核磁T2谱 渗吸置换 长6砂岩 

分 类 号：TE357.12[石油与天然气工程—油气田开发工程]