Predicting Water Abundance in the Strata Surrounding Coal Seams Based on the Hydrodynamic Evolution of Groundwater

Due to tectonics, it is impossible in some areas to accurately assess the water abundance of strata based solely on the current groundwater level. This study focused on an aquifer located ≈ 10 m above the no. 15 coal seam in the Shouyang Block of the Qinshui Basin, Shanxi Province, China. Well-logging data was used to determine the aquifer water abundance. After classifying and analyzing the water-rich aquifer and its effect on the water output of the discharge wells, development measures were proposed. The strongest hydrodynamic force was observed in the superposition area of the syncline core + syncline core. In contrast, the least hydrodynamic force was observed in the superposition area of the anticline core + anticline core. The southeastern and northeastern regions of the study area exhibited the greatest water abundance. Strongly hydrodynamic coalbed methane (CBM) wells have high daily water production, which makes drainage and pressure reduction challenging. Therefore, CBM development should be approached cautiously. CBM wells with strong water abundance have high water production, and efforts should be made to avoid aquifer communication during development. Wells with weak hydrodynamics and weak water abundance have low water production, making drainage and pressure reduction easier. Reducing reservoir damage can further enhance the gas production potential. The findings of this study provide a methodology and reference for calculating aquifer water abundance and forecasting daily water production.