Revealing reservoir dynamics: how CO2 injection reshapes permeability in coalbed methane recovery

作者：Yu Zhao, Hong Li, Xiaoming Li, Kaoshan Dai · 发表于：Geomechanics and Geophysics for Geo-Energy and Geo-Resources · 年份：2025 · DOI：10.1007/s40948-025-01018-1 · 被引用次数：3 · 研究领域：Coal Properties and Utilization、Hydrocarbon exploration and reservoir analysis、Hydraulic Fracturing and Reservoir Analysis

Abstract Coalbed methane (CBM) reservoirs have emerged as a crucial source of natural gas, but their efficient recovery remains challenging due to complex interactions between mechanical deformation, fluid migration, and permeability evolution. CO 2 -enhanced coalbed methane (CO 2 -ECBM) recovery has gained attention as a promising technique for improving gas extraction while simultaneously sequestering CO 2 . However, a comprehensive understanding of the reservoir's mechanical behaviour and permeability evolution during CO 2 injection is still lacking. To address this gap, we develop a 3D thermo-hydro-mechanical (THM) coupled numerical model to simulate the CO 2 -ECBM process. This model captures reservoir deformation, geological formation shifts, and surface responses while integrating field monitoring data to enhance accuracy and reliability. A key innovation of this study is the coupled analysis of simulated surface deformations with measured data, enabling a more precise assessment of permeability evolution and mechanical responses. A representative 2D cross-section of the coal seam is analysed to examine how injection pressure and production temperature influence gas pressure, permeability, and reservoir deformation. The results indicate that surface micro-deformation induced by CO 2 injection arises from the interplay of geo-stress, injection pressure, gas adsorption/desorption, and temperature effects. Notably, CO 2 adsorption-driven expansion outweighs CH 4 desorptio...