基于核磁共振和磁共振成像的低渗透岩芯CO_(2)-H_(2)O两相驱替特征研究  

CO_(2)-H_(2)O two-phase displacement characteristics of low permeability core using nuclear magnetic resonance and magnetic resonance imaging techniques

作　　者：赵艳[1,2] 杨柳[1,2] 奚茹茹 耿振坤 张谦 马雄德[1,2] ZHAO Yan;YANG Liu;XI Ru-ru;GENG Zhen-kun;ZHANG Qian;MA Xiong-de(School of Water and Environment,Chang’an University,Xi’an,Shaanxi 710054,China;Key Laboratory of Subsurface Hydrology and Ecological Effects in Arid Region of Ministry of Education,Chang’an University,Xi’an,Shaanxi 710054,China;Petro China Changqing Oilfield Company Planning Department,Xi’an,Shaanxi 710018,China)

机构地区：[1]长安大学水利与环境学院,陕西西安710054 [2]长安大学旱区地下水文与生态效应教育部重点实验室,陕西西安710054 [3]中国石油长庆油田分公司规划计划部,陕西西安710018

出　　处：《岩土力学》2023年第6期1636-1644,共9页Rock and Soil Mechanics

基　　金：国家自然科学基金(No.42007174);中国博士后科学基金(No.2021M692736);长安大学中央高校基本科研业务费专项资金(No.300102293206)。

摘　　要：致密岩石的孔隙结构特征对CO_(2)和水之间的驱替行为以及CO_(2)相的流动特征具有重要影响,且残余水饱和度最终将影响碳封存的效率和安全性,因此,深入探究致密岩芯CO_(2)-H_(2)O两相驱替特征具有重要意义。利用取自鄂尔多斯盆地深部储层的天然低渗透岩芯,利用核磁共振(NMR)及磁共振成像(MRI)技术对其内部的气液两相驱替特征及其影响因素进行了可视化研究。在将岩芯孔隙结构进行定性和定量化表征后,可知不同的驱替模式与岩芯孔隙结构密切相关:具有较强非均质性和各向异性的岩芯更有利于指进现象的发生,具有较大孔隙度和较高渗透率的岩芯则呈现活塞式驱替模式。指进现象有助于气相的运移,会造成气相的提前突破,导致较高的残余水饱和度及较低的驱替效率。The pore structure characteristics of tight rocks have an important impact on the displacement behavior between CO_(2)and water,as well as the flow characteristics of CO_(2).The residual water saturation will ultimately affect the efficiency and safety of CO_(2)geological storage.Therefore,it is of great significance to further explore the CO_(2)-H_(2)O two-phase displacement characteristics of tight cores.In this study,the two-phase displacement characteristics and its influencing factors of natural low-permeability cores from deep reservoirs in Ordos Basin were visualized using nuclear magnetic resonance(NMR)and magnetic resonance imaging(MRI)techniques.After qualitative and quantitative characterization of core pore structure,it is found that displacement patterns are closely related to core pore structure.Cores with strong heterogeneity and anisotropy are more conducive to the formation of fingering phenomena,while cores with large porosity and high permeability show piston-like displacement pattern.Fingering phenomena contributes to the migration of gas phase and can lead to the premature breakthrough of CO_(2),resulting in high residual water saturation and low displacement efficiency.

关 键 词：CO_(2)地质封存 驱替效率 孔隙结构特征 相对渗透率 核磁共振 

分 类 号：TU457[建筑科学—岩土工程]