煤储层流体微观相互作用的动态地质效应

The production of coalbed methane (CBM) includes several processes such as the desorption and diffusion of gas from coal and the laminar flow of fluid (gas-water) in the coal seam. It is essentially a multiple and comprehensive geological interaction process among coal matrix, gas, and water, resulting from changes of temperature, pressure, and stress in coal reservoirs. To disclose these interaction mechanisms and multiple geological effects is a key of the study of the CBM production process. Based on series of low-field NMR simulation experiments on coals with varies of coal rank, this project would found several quantified methods for characterizing methane adsorption capacity, gas/water saturation, and relatively permeability curve of gas and water. This project would continence on researches about the mechanisms of the occurrences, transportation, and interactions of fluid in coal pore system. Then, this project would quantify the transformation of phase-states among the bulk-, capillary-, and adsorbed-methane and the bulk-, capillary-, and adsorbed- moistures with the changes of reservoir temperature and pressure, and evaluate the characteristics of relative permeability curves of gas and water for coals with different coal rank and coal petrologic type. This project would be concluded by founding the theoretical model for evaluation of multiple-stage and multiple-phase fluid transportation in CBM reservoirs, and disclosing the dynamic geologic effects resulting from the microscopic interactions of gas and water in coal reservoirs. This project could provide some critical suggestions for commercial and high-effective development of CBM in China.

煤层气的产出过程包括脱附、解吸、扩散、渗流等，其实质即"在压力、应力、温度环境下煤基质与气、水多相流体间的多级动态地质作用过程"。揭示煤储层与流体间微观相互作用机制，探讨其引起的综合动态地质效应，是揭示煤层气产出机理的关键所在。本项目基于对系列不同煤级煤的气、水低场核磁共振物理模拟实验，形成煤的甲烷吸附量、含气/水饱和度，气、水相对渗透率的定量、综合表征技术体系；揭示煤储层孔隙系统中气、水的赋存与运移规律，阐明煤储层多相介质系统中气、水微观作用机理；基于对"三态水"和"三态甲烷"随储层环境条件（温度、压力等）变化的相态转化与变化过程的定量解析，揭示不同煤级和不同煤岩类型煤的气、水相对渗透率曲线特征，构建煤储层多级、多相流的理论模型，综合阐明煤储层流体微观相互作用的动态地质效应，为我国煤层气的合理高效开发提供理论依据。

本项目基于对系列不同煤级煤的气、水低场核磁共振物理模拟实验，研究阐明了煤中“多态水（表面吸附态、毛管束缚态和自由态）”和“多态甲烷（吸附态、孔束缚态和游离态）”在煤中的赋存和运移规律；研发了基于低场核磁共振的煤储层润湿性、全孔径分布、甲烷吸附量和气、水相对渗透率的定量分析技术；提出了煤层注二氧化碳提高煤层气排采效率的定量化理论模型，揭示了煤层注二氧化碳引起的润湿性变化等气、水微观作用机理；最终形成了原位煤储层多相流体综合表征技术体系，为我国煤层气高效开发提供了技术支撑。. 基于本项目共发表第一/通讯作者国际SCI论文17篇、E I论文6篇、核心论文11篇；以第一发明人身份申报国家发明专利14项（授权7项，成果转让许可2项）。项目负责人受邀在国内外做学术报告8次，项目成员参加国内外学术会议并做学术报告10余次。本项目培养研究生18名，培养高级职称人员3人，项目负责人入选教育部长江学者（青年）特聘教授。