Coupled Effects of Stress, Moisture Content and Gas Pressure on the Permeability Evolution of Coal Samples: A Case Study of the Coking Coal Resourced from Tunlan Coalmine

Deep coalbed methane (CBM) is widely distributed in China and mainly commercially exploited the Qinshui basin. The situ stress moisture content are key factors affecting permeability of CH4-containing coal samples. Therefore, considering coupled effects compressing infiltrating on gas could be more accurate to reveal CH4 seepage characteristics CBM reservoirs. In this study, samples sourced from Tunlan coalmine were employed conduct triaxial loading tests. Several findings concluded: (1) test, effect confining gas-containing greater than that axial stress. (2) versus pressure curve presents a ‘V’ shape evolution trend, which minimum was obtained at 1.1MPa. (3) decreased exponentially with increasing content. Specifically, as 0.18% 3.15%, by about 70%. These results expected provide foundation for efficient exploitation