Coal reservoir characteristics of the Shizhuang South Block, Southeastern Qinshui Basin

The characteristics of coal reservoirs have considerable importance for the generation, accumulation, and production of coalbed methane. An analysis of geological and test data has been conducted to assess coal quality, pore permeability, and gas content. The results reveal that vitrinite reflectance falls within the range of 3.08% to 3.41%. Vitrinite constitutes the primary component, accounting for an average of 74.1%. The porosity of the coal is limited, with coal seam No.3 exhibiting porosity between 3.43% and 6.02%, and coal seam No.15 averaging at 4.74%. The permeability of the coal reservoirs is exceedingly low, spanning from 0.01 to 0.18 mD. The gas content varies significantly among coal seams, with coal seam No.15 generally outperforming coal seam No.3. Mechanical properties indicate that the coal displays a low Young's modulus, a high Poisson's ratio, and low compressive strength. Furthermore, the critical desorption pressures are relatively low, belonging to undersaturated coalbed methane reservoir.