致密气藏注CO_(2)提高采收率及封存效果主控因素研究  

Research on Key Factors Influencing CO_(2) Injection for Enhanced Gas Recovery and Sequestration in Tight Gas Reservoirs

作　　者：吴佳琦 杜旭林 白玉湖 徐兵祥 王苏冉 WU Jiaqi;DU Xulin;BAI Yuhu;XU Bingxiang;WANG Suran(CNOOC Research Institute Co.,Ltd.,Beijing 100028,China;State Key Laboratory of Offshore Oil and Gas Exploitation,Beijing 100028,China)

机构地区：[1]中海油研究总院有限责任公司,北京100028 [2]海洋油气高效开发全国重点实验室,北京100028

出　　处：《油气与新能源》2025年第2期92-102,共11页Petroleum and new energy

基　　金：国家自然科学基金面上项目“深层页岩储层井间窜扰缝内传质机理及缝网参数反演方法研究”(52474051)。

摘　　要：致密气藏注CO_(2)既可提高天然气资源采收率,又能有效实现碳封存,但由于CO_(2)提高采收率及封存效果受多因素影响,作用机制不明确,亟待开展更深入的研究。通过建立致密储层气水两相渗流的嵌入式离散裂缝模型,结合考虑气体组分变化和人工裂缝应力敏感,采用有限体积法对所建立的渗流数学模型进行离散求解,并通过商业软件tNavigator验证模型的有效性。在此基础上,重点分析了储层含水、人工裂缝、工作制度等多因素对CO_(2)提高采收率及封存效果的影响。结果表明:相较于衰竭开发,致密气藏注CO_(2)能有效提高气藏采收率并实现碳封存,其中转注时机、原始含水饱和度及裂缝半长是影响CO_(2)提高采收率及封存效果的主控因素。在开展注CO_(2)开发方案设计及地质封存选区评价时,应避开风险较大的高含水区域,并合理优化CO_(2)注入时机和压裂改造工艺。Injecting CO_(2) into tight gas reservoirs can enhance the recovery rate of natural gas resources while effectively achieving carbon sequestration.It is urgent to conduct further in-depth research since the effectiveness of CO_(2) extraction and sequestration is influenced by multiple factors and the underlying mechanisms remain unclear.This paper establishes an embedded discrete fracture model for gas-water two-phase flow in tight reservoirs,comprehensively considers variations in gas composition and the stress sensitivity of artificial fractures,discretely solves the developed flow mathematical model using the finite volume method,verifies the model’s validity by commercial software tNavigator,and significantly analyzes he impact of such various factors as reservoir water saturation,artificial fractures,and operational regimes on the effectiveness of CO_(2) extraction and sequestration.The research indicates that CO_(2) injection into tight gas reservoirs can effectively improve gas recovery rates and achieve carbon sequestration compared to depletion development and the timing of injection,initial water saturation,as well as fracture half-length are the key factors influencing CO_(2) extraction and sequestration effectiveness.when designing CO_(2) injection development plans and evaluating geological sequestration sites,it is essential to avoid high water saturation areas with greater risks and to optimize the timing of CO_(2) injection and fracturing modification processes.

关 键 词：致密气藏 注CO_(2) CO_(2)封存 提高采收率 主控因素 数值模拟 

分 类 号：TE357[石油与天然气工程—油气田开发工程]