Performance and enhanced oil recovery efficiency of an acid-resistant polymer microspheres of anti-CO_(2) channeling in low-permeability reservoirs  

作　　者：Hai-Zhuang Jiang Hong-Bin Yang Ruo-Sheng Pan Zhen-Yu Ren Wan-Li Kang Jun-Yi Zhang Shi-Long Pan Bauyrzhan Sarsenbekuly 

机构地区：[1]State Key Laboratory of Deep Oil and Gas,China University of Petroleum(East China),Qingdao,266580,Shandong,PR China [2]Oil and Gas Engineering Research Institute,CNPC Jilin Oilfield Company,Songyuan,138000,Jilin,PR China [3]School of Petroleum Engineering,China University of Petroleum(East China),Qingdao,266580,Shandong,PR China [4]School of Energy and Petroleum Industry,Kazakh-British Technical University,Almaty,050000,Kazakhstan

出　　处：《Petroleum Science》2024年第4期2420-2432,共13页石油科学（英文版）

基　　金：supported by the Fund of State Key Laboratory of Deep Oil and Gas,China University of Petroleum (East China) (SKLDOG2024-ZYRC-06);Key Program of National Natural Science Foundation of China (52130401);National Natural Science Foundation of China (52104055,52250410349);Major Science and Technology Project of China National Petroleum Corporation Limited (2021ZZ01-08);Shandong Provincial Natural Science Foundation,China (ZR2021ME171)。

摘　　要：CO_(2) flooding is a vital development method for enhanced oil recovery in low-permeability reservoirs,However,micro-fractures are developed in low-permeability reservoirs,which are essential oil flow channels but can also cause severe CO_(2) gas channeling problems.Therefore,anti-gas channeling is a necessary measure to improve the effect of CO_(2) flooding.The kind of anti-gas channeling refers to the plugging of fractures in the deep formation to prevent CO_(2) gas channeling,which is different from the wellbore leakage.Polymer microspheres have the characteristics of controllable deep plugging,which can achieve the profile control of low-permeability fractured reservoirs.In acidic environments with supercritical CO_(2),traditional polymer microspheres have poor expandability and plugging properties.Based on previous work,a systematic evaluation of the expansion performance,dispersion rheological properties,stability,deep migration,anti-CO_(2) channeling and enhanced oil recovery ability of a novel acid-resistant polymer microsphere(DCNPM-A)was carried out under CQ oilifield conditions(salinity of85,000 mg/L,80℃,pH=3).The results show that the DCNPM-A microsphere had a better expansion performance than the traditional microsphere,with a swelling rate of 13.5.The microsphere dispersion with a concentration of 0.1%-0.5%had the advantages of low viscosity,high dispersion and good injectability in the low permeability fractured core.In the acidic environment of supercritical CO_(2),DCNPM-A microspheres showed excellent stability and could maintain strength for over 60 d with less loss.In core experiments,DCNPM-A microspheres exhibited delayed swelling characteristics and could effectively plug deep formations.With a plugging rate of 95%,the subsequent enhanced oil recovery of CO_(2) flooding could reach 21.03%.The experimental results can provide a theoretical basis for anti-CO_(2)channeling and enhanced oil recovery in low-permeability fractured reservoirs.

关 键 词：Low-permeability reservoir Anti-CO_(2)channeling Polymer microsphere Acid resistance 

分 类 号：TE348[石油与天然气工程—油气田开发工程]