注CO2过程中沥青质沉淀对低渗储层的伤害及对润湿性的影响  

Formation Damage and Wettability Change due to Asphaltene Precipitation during CO2 Injection in Low-permeability Reservoirs

作　　者：钱坤 杨胜来 黄飞 窦洪恩 王千 QIAN Kun;YANG Shenglai;HUANG Fei;DOU Hongen;WANG Qian(State Key Laboratory of Petroleum Resources and Prospecting,China University of Petroleum(Beijing),Beijing 102249,P R of China;Exploration and Development Research Institute,PetroChina,Beijing 100083,P R of China)

机构地区：[1]油气资源与探测国家重点实验室(中国石油大学(北京)),北京102249 [2]中国石油勘探开发研究院,北京100083

出　　处：《油田化学》2020年第3期536-541,共6页Oilfield Chemistry

基　　金：国家油气重大专项“大型油气田及煤层气开发”十三五课题:国内油气开发发展战略研究(项目编号2016ZX05016-006)。

摘　　要：沥青质沉淀是注CO2提高采收率过程中普遍存在的问题,常导致储层孔喉堵塞和润湿性改变。利用岩心驱替实验并结合核磁共振技术,定量表征了不同CO2注入压力下沥青质沉淀对低渗透储层的伤害程度和引起的润湿性变化。结果表明,随着CO2注入压力的增加,采出原油的黏度和沥青质含量不断减小,剩余油中的沥青质含量不断增加。CO2注入压力分别为9.1、16.2、24.1 MPa时,岩心的渗透率损失率为2.40%、7.41%、8.32%,岩心驱替后的混合润湿指数下降了0.04、0.12和0.14,表观接触角增加5°、12°、19°。CO2注入压力越高,沥青质沉淀越严重,对低渗储层的孔隙度和渗透率伤害越大。Asphaltene precipitation is a common problem in the process of CO2 enhanced oil recovery project,which usually causes the pore throat plugging and wettability change of the reservoir.The formation damage and wettability change due to asphaltene precipitation was quantitatively evaluated under different CO2 injection pressures through core flooding test and NMR technique.The Experiment results showed that the viscosity and asphaltene content of the produced oil decreased and the asphaltene content of the residual oil increased with increasing injection pressure of CO2.When the injection pressure of CO2 was 9.1,16.2 and 24.1 MPa,the permeability reduction of core was 2.40%,7.41%and 8.32%,the mixed wettability index decreased 0.04,0.12 and 0.14,and the apparent contact angle increased 5°,12°and 19°,respectively.The higher injection pressure of CO2,the more serious asphaltene precipitation was,which would result in greater damage to the porosity and permeability of low permeability reservoir.

关 键 词：二氧化碳(CO2) 沥青质 沉淀 核磁共振 渗透率 润湿性 

分 类 号：TE258[石油与天然气工程—油气井工程]