扩散吸附作用下CO_(2)非混相驱微观渗流特征模拟  

Simulation of microscopic seepage characteristics of CO_(2) immiscible flooding under the effect of diffusion and adsorption

作　　者：崔传智[1] 李静 吴忠维 CUI Chuanzhi;LI Jing;WU Zhongwei(School of Petroleum Engineering,China University of Petroleum(East China),Qingdao 266580,Shandong,China;School of Petroleum Engineering,Yangtze University,Wuhan 430100,China)

机构地区：[1]中国石油大学(华东)石油工程学院,山东青岛266580 [2]长江大学石油工程学院,武汉430100

出　　处：《岩性油气藏》2024年第6期181-188,共8页Lithologic Reservoirs

基　　金：国家自然科学基金面上项目“致密油藏多段压裂水平井时空耦合流动模拟及参数优化方法”(编号:51974343)资助。

摘　　要：利用数值模拟方法建立CO_(2)非混相驱数值模型,使用水平集法模拟扩散吸附作用下CO_(2)非混相驱和近混相驱的微观渗流规律,并对CO_(2)在孔隙中的微观渗流特征及扩散吸附特征进行研究,选取注入速度、扩散系数、吸附反应速率常数等参数研究近混相驱微观渗流特征的影响因素。研究结果表明:①相场法CO_(2)驱数值模拟采出程度为51.29%,水平集法CO_(2)驱数值模拟采出程度为53.60%,因此水平集法更适用于CO_(2)非混相驱的渗流过程模拟。②非混相驱条件下,CO_(2)优先向大孔隙扩散,采收率为87.7%,出口气体体积分数为71.60%,CO_(2)最大表面吸附浓度为3.16×10-4mol/m^(2);近混相驱条件下,CO_(2)更易向小孔隙扩散,采收率为91.1%,出口含气率为97.01%,CO_(2)最大表面吸附浓度为5.81×10-4mol/m^(2)。③近混相驱微观渗流特征受注入速度、扩散系数、吸附反应速率常数等因素影响。注入速度增大,出口含气率和采收率均提高;扩散系数和吸附反应速率常数增大,会使采收率提高,出口含气率下降。Based on a two-dimensional model,a numerical simulation method was used to establish a numerical model of CO_(2) immiscible flooding,and the level set method is used to simulate the microscopic seepage laws of CO_(2) immiscible flooding and near miscible flooding under diffusion and adsorption.The microscopic seepage characteristics and diffusion adsorption characteristics of CO_(2) in pores were studied,and the influences of the injection velocity,diffusion coefficient,and adsorption reaction rate constant on the microscopic seepage characteristics of near miscible flooding were analyzed.The results show that:(1)The degree of reserve recovery of the CO_(2) flooding numerical simulation using the phase field method is 51.29%,and the degree of reserve recovery of the CO_(2) flooding numerical simulation using the level set method is 53.60%.The level set method is more suitable for simulating the seepage process of CO_(2) immiscible flooding.(2)Under immiscible flooding conditions,CO_(2) preferentially diffuses into large pores,with a recovery efficiency of 87.7%,an outlet gas content rate of 71.60%,and a maximum CO_(2) surface adsorption concentration of 3.16×10-4 mol/m^(2).Under the conditions of near miscible flooding,CO_(2) is more likely to diffuse into small pores,with a recovery efficiency of 91.1%,an outlet gas content rate of 97.01%,and a maximum CO_(2) surface adsorption concentration of 5.81×10-4 mol/m^(2).(3)The microscopic seepage of miscible flooding is influenced by factors such as the injection velocity,diffusion coefficient,and adsorption reaction rate constant.The injection rate increases,resulting in an increase in both the gas content and recovery rate at the outlet.An increase in diffusion coefficient and adsorption reaction rate constant will lead to an increase in recovery efficiency and a decrease in outlet gas content.

关 键 词：CO_(2)非混相驱 微观渗流特征 注入速度 扩散系数 吸附反应速率常数 采收率 数值模拟 

分 类 号：TE357.45[石油与天然气工程—油气田开发工程] P618.13[天文地球—矿床学]