结构无序性对多孔介质中CO_(2)驱指进及提采的影响  

Effect of structural disorder on fingering and enhanced oil recovery of CO_(2) flooding in porous media

作　　者：和龙 何文静 牛泽豪 HE Long;HE Wen-jing;NIU Ze-hao(College of Mechanical and Electrical Engineering,Shaanxi University of Science&Technology,Xi′an 710021,China)

机构地区：[1]陕西科技大学机电工程学院,陕西西安710021

出　　处：《陕西科技大学学报》2024年第4期94-100,共7页Journal of Shaanxi University of Science & Technology

基　　金：国家自然科学基金项目(52106204);陕西省西安市科协青年人才托举计划项目(095920221332)。

摘　　要：在CO_(2)非混相驱替过程中,指进的发生显著降低采收率.已有研究主要关注驱替条件及流体物性等对指进的影响,而多孔介质非均质性的影响仅局限于润湿性的作用,储层孔隙的结构无序性对指进模式的调控及提采机制仍有待探究.本文提出了定量描述多孔介质无序性的无量纲参数——偏移度,建立了无序多孔介质模型,采用相场法追踪相界面演变,研究CO_(2)驱中偏移度及驱替压力对指进的影响.结果发现,偏移度增大时促进指进的形成,导致残余油饱和度升高.在不同的注入压力下,获得了两种典型的流动模式:指进和稳定驱替.随着偏移度的增加,从指进转变到稳定驱替所需要的临界压力逐渐增大.且随着注入压力的增大,不同偏移度下突破时刻的残余油饱和度均下降,但同一压力下,偏移度越高,残余油饱和度越大.这将有助于我们了解不同储层结构中CO_(2)驱替前沿运移规律,对提高原油采收率具有指导意义.During the CO_(2) immiscible displacement process,the presence of fingering significantly hampers the recovery rate.Previous researches have primarily concentrated on assessing the impact of displacement conditions and fluid properties on fingering.The role of heterogeneity in porous media was limited to wettability.The disordered configuration of reservoir pores remains an unexplored aspect in terms of its influence on fingering and enhanced oil recovery mechanisms.We used a nondimensional parameter to quantitatively characterize the structural disorder in porous media during displacement,established a model for disordered porous media,employed the phase field method to monitor the two-phase interface,and investigated the effects of structural disorder and displacement pressure on fingering in CO_(2) flooding.The findings reveal that an increase in offset facilitates fingering formation,resulting in a rise in residual oil saturation.Two distinct flow patterns:fingering,and stable displacement,emerge under varying injection pressures.With an escalating offset,the critical pressure needed to transition from fingering to stable displacement gradually rises.Additionally,under different injection pressures,the residual oil saturation at the breakthrough time decreases as the offset increases.Nevertheless,at the same pressure level,a higher offset corresponds to a greater residual oil saturation.These insights contribute to a better understanding of CO_(2) displacement front migration patterns in diverse reservoir structures,offering valuable guidance for enhancing oil recovery.

关 键 词：指进 CO_(2)驱 无序多孔介质 提采 

分 类 号：TE31[石油与天然气工程—油气田开发工程]