深层高阶煤层CO-ECBM技术研究与应用启示——以沁水盆地晋中地区为例

Research and insights for application of CO-ECBM technology in deep high-rank coal seams: a case study of Jinzhong block, Qinshui Basin

郑永旺 崔轶男 李鑫 肖翠 郭涛 张登峰

ZHENG Yongwang CUI Yinan LI Xin XIAO Cui GUO Tao ZHANG Dengfeng

1. 中国石化 华东油气分公司 勘探开发研究院, 南京 210000; 2. 中国石化 深层煤层气勘探开发重点实验室, 南京 210000; 3. 昆明理工大学 化学工程学院, 昆明 650500

1. Exploration and Development Research Institute, SINOPEC East China Oil and Gas Company, Nanjing, Jiangsu 210000, China; 2. SINOPEC Key Laboratory of Deep Coalbed Methane Exploration and Development, Nanjing, Jiangsu 210000, China; 3. Faculty of Chemical Engineering, Kunming University of Science and Technology, Kunming, Yunnan 650500, China

深层高阶煤层资源潜力大，但具有“强吸附、难解吸”的特点，常规开发方式难以实现效益动用。与化学驱、热力驱等其他提高采收率技术相比，CO2-ECBM(CO2地质封存及强化煤层开采)技术具有节能减排和提高煤层气采收率双重效益。为明确CO2吸附、解吸特性，论证CO2-ECBM技术提高深层高阶煤层气采收率可行性，助力深层高阶煤层气产能释放，以沁水盆地晋中地区为研究对象，开展深层高阶煤层CO2吸附、解吸特征研究实验。研究结果表明，随着平衡压力的增加，煤层对CH4的吸附量逐渐增加，而受煤层孔裂隙发育特征及CO2特征影响，煤层对CO2的吸附量呈先持续上升再在临界压力附近骤降后大幅上升的特征。深层高阶煤层对CO2的吸附能力约为CH4的2～5倍，超临界CO2在煤层中的吸附能力更强，CO2的敏感解吸压力为CH4的3/4，且吸附于煤层后，CO2呈现出明显的吸附、解吸滞后特征，大比例CO2以吸附封存和残余封存形式滞留在煤层中无法脱附，成为实现大规模封存CO2和替换CH4的有利条件。通过实验结果分析，明确了深层高阶煤层气开展CO2-ECBM具备大幅提高采收率的可行性。矿场应用中，可通过超前注气、加大注入压力等方式提高气藏压力水平，提升竞争吸附效率，同时低敏感解吸压力也表明注入CO2后返排率较高，需考虑CO2循环利用。

Deep high-rank coal seams have significant resource potential, but exhibit characteristics of “strong adsorption and weak desorption”, making it challenging to effectively utilize with conventional development methods. Compared with other enhanced recovery technologies such as chemical flooding and thermal flooding, CO2-ECBM (CO2 geological sequestration-Enhanced Coal Bed Methane Recovery) technology offers dual benefits of energy conservation and emission reduction, and increased recovery rates of coalbed methane. In order to clarify the characteristics of CO2 adsorption and desorption, demonstrate the feasibility of CO2-ECBM technology in enhancing the recovery of deep high-rank coalbed methane, and help release the productivity of deep high-rank coalbed methane, this study focused on the Jinzhong block, Qinshui Basin, and conducted experimental research on the CO2 adsorption and desorption characteristics of deep high-rank coal seams. The research results showed that the adsorption capacity of CH4 in coal seams increased gradually with rising equilibrium pressures. In contrast, the adsorption capacity of CO2 in coal seams initially increased, then sharply dropped near the critical pressure, followed by a significant rise, which was influenced by the pore and fracture development characteristics of the coal seams and the properties of CO2. The adsorption capacity of CO2 in deep high-rank coal seams was about 2 to 5 times that of CH4, and the adsorption capacity of supercritical CO2 in coal seams was stronger. The sensitive desorption pressure of CO2 was 3/4 of that of CH4. Once adsorbed in coal seams, CO2 showed an obvious adsorption/desorption lag, with a large proportion of CO2 remaining in coal seams in the form of adsorbed storage and residual storage, which provided favorable conditions for large-scale CO2 storage and CH4 replacement. Through the analysis of experimental results, it was clear that developing CO2-ECBM in deep high-rank coal seams was feasible and could significantly enhance coalbed methane recovery. In field application, the pressure level of gas reservoir could be increased through methods such as advanced gas injection and increasing injection pressure, thereby enhancing competitive adsorption efficiency. Additionally, the low sensitive desorption pressure indicated a high backflow rate after CO2 injection, suggesting that CO2 recycling should be considered.

中国石化科技部项目“华东探区深部煤层气富集规律与有效开发技术”(P23205)资助。

https://doi.org/10.11781/sysydz2025010143