非均质多孔介质超临界CO_(2)非混相驱替特征及机理研究  

STUDY ON CHARACTERISTICS AND MECHANISM OF IMMISCIBLE DISPLACEMENT OF SUPERCRITICAL CO_(2)IN HETEROGENEOUS POROUS MEDIA

作　　者：赵海军[1,2] 魏爱华 彭昊 张凯[5] 陈媛瑶 ZHAO Haijun;WEI Aihua;PENG Hao;ZHANG Kai;CHEN Yuanyao(State Key Laboratory of Lithospheric and Environmental Coevolution,Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,China;Innovation Academy for Earth Science,Chinese Academy of Sciences,Beijing 100029,China;College of Earth and Planetary Sciences,University of Chinese Academy of Sciences,Beijing 100049,China;School of Water Resources and Environment,Hebei Geo University,Shijiazhuang 050031,China;College of Geoscience and Surveying Engineering,China University of Mining and Technology,Beijing 100083,China)

机构地区：[1]中国科学院地质与地球物理研究所,岩石圈演化与环境演变全国重点实验室,北京100029 [2]中国科学院地球科学研究院,北京100029 [3]中国科学院大学,地球与行星科学学院,北京100049 [4]河北地质大学,水资源与环境学院,石家庄050031 [5]中国矿业大学(北京)地球科学与测绘工程学院,北京100083

出　　处：《工程地质学报》2024年第5期1825-1837,共13页Journal of Engineering Geology

基　　金：国家自然科学基金项目(资助号:42141009,42372315)。

摘　　要：为深入理解超临界CO_(2)在非均质储层中的非混相驱替过程,探索其流动特性及对多孔介质流体动力学的影响,为CO_(2)增强油气采收率和地质碳储存技术提供科学依据,采用基于Navier-Stokes方程与Cahn-Hilliard方程耦合的微观两相流模型,结合Voronoi多边形构造技术建立了具有真实孔隙结构特征的非均质多孔介质模型。通过模拟计算,详细描述了不同条件下CO_(2)驱替过程中的流体动力学行为和界面特征,研究了流体界面形态的演变和驱替效率的影响因素。结果表明:超临界CO_(2)注入后,不同模型内均出现了指进特征和复杂的非混相界面;孔道结构特征决定了毛细力大小,影响CO_(2)驱替前缘的稳定性,大孔道易形成指进现象,而狭窄孔道受毛细阻力与黏滞力影响,促使CO_(2)渗流路径转向或分叉,并导致孔隙压力不均匀分布;孔道内的黏滞力阻碍CO_(2)推进,适度调节CO_(2)的黏度和密度有助于提高驱替效率;高毛管数条件下,驱替压力导致流体相界面变得不稳定,CO_(2)优势渗流通道数量增多,指进渗流通道宽度拓宽,在黏滞力作用下出现了非连续的卡断现象;长时间的驱替过程显著提高CO_(2)饱和度,但伴随高能耗损失,驱替效率在CO_(2)突破后期逐渐下降。因此,调控超临界CO_(2)的物理性质、优化控制注入速率,能有效改善CO_(2)在地层中的分布和驱替路径,是提高CO_(2)驱替效率和优化地层开发的重要手段。The study aimed to gain a deeper understanding of the immiscible displacement process of supercritical CO_(2) inheterogeneous reservoirs, investigating its flow characteristics and impact on fluid dynamics in porous media. Thisresearch provides a scientific basis for CO_(2)-enhanced oil and gas recovery as well as geological carbon storagetechnology. A microscopic two-phase flow model, based on the coupling of the Navier-Stokes equation and theCahn-Hilliard equation, was employed. Combined with Voronoi polygon construction technology, the studyestablished a heterogeneous porous medium model that realistically represents pore structure characteristics.Through simulation, the fluid dynamic behavior and interface characteristics of the CO_(2) displacement processunder different conditions were detailed, and the factors affecting the evolution of the fluid interface morphologyand displacement efficiency were analyzed. The results indicated that after the injection of supercritical CO2,multiple preferential flow channels and complex immiscible interfaces were formed. The characteristics of thepore structure determine the magnitude of capillary forces, which affect the stability of the CO_(2) displacementfront. Larger pores are prone to fingering, whereas narrower pores, with higher capillary resistance, can causeCO_(2) flow paths to divert or branch, leading to an uneven distribution of pore pressure. When the contact angle isacute and small, the suppression of CO_(2) fingering becomes more apparent. The properties of CO_(2) also directlyaffect the displacement effect, with adjustments in its viscosity and density helping to improve displacementefficiency. The injection rate significantly influenced CO_(2) displacement, with high-rate injection favoring theexpansion of preferential permeable channels and improving displacement efficiency. Although an extendeddisplacement process significantly increased CO_(2) saturation, it also involved high energy consumption, withdisplacement efficiency gradually decreasing in the

关 键 词：超临界CO_(2) 非混相驱替 相场法 非均质模型 孔隙尺度模拟 

分 类 号：TE38[石油与天然气工程—油气田开发工程]