Advantageous Seepage Channel in Coal Seam and its Effects on the Distribution of High-yield Areas in the Fanzhuang CBM Block, Southern Qinshui Basin, China

Results of stress sensitivity experiments show that, when the confining pressure reaches 15.5 MPa, six coal cores have strong stress sensitivity effect (SSE) and cleat compressibility varying from 0.0286 to 0.0725 MPa−1. The development of coalbed methane (CBM) is a process of drainage and pressure reduction, which causes inevitable stress-related damage to coal reservoirs. CBM production is affected by different stress-related damage levels, and the damage level depends on different reservoir conditions, working systems, and development stages. The Gu, Huagu, and Pu-Punan zones have high-yield wells with NW–SE distribution, while the Huayna and Huaxi zones have high-yield wells with NE–SW distribution. Based on the stress damage mechanism of reservoir permeability, the factors that control SSE are tectonic stress field, reservoir pressure, and fracture pressure, which in turn affect the productivity changes of CBM wells.