Groundwater Flow Fields and Patterns in Heterogeneous Aquifer Induced by Mine Water Injection and Storage Under Different Well Configurations

Mine water injection and storage (MWIS) represent a crucial method for the management of unconventional water resource in the mining regions of China. The flow fields and patterns within heterogeneity porous media during the MWIS process are complex and significantly influenced by well configurations. This study aims to offer a numerical perspective for the evaluation of MWIS flow fields and patterns associated with diverse well configurations in different heterogeneous aquifers. The simulation results of various well configuration scenarios, including vertical, slanted and horizontal wells, demonstrate that well configuration exerts a profound influence on the flow fields and patterns of MWIS. The injected mine water primarily spreads radially and groundwater level gradually diminishes as the distance from the wellbore increases in the vertical well. Conversely, horizontal wells can notably augment the contact area between the injected mine water and the aquifer, leading to a more uniform distribution of the flow field and higher injection efficiency. Slanted wells exhibit a combination of vertical and horizontal flow characteristics, which can be adjusted in accordance with specific geological conditions to optimize the MWIS effect. Overall, both horizontal and slanted wells exhibit water storage capacities that are approximately 1.77 to 2.65 times greater than that of vertical wells. Effective mine water capacity accumulates primarily during the initial phase, followed by a rapid decline in subsequent reserves. The results suggest that appropriate arrangement of well configurations and injection pressure can effectively enhance the MWIS efficiency. Hydraulic fracturing is the fundamental approach to sustaining MWIS capacity. This research provides a theoretical foundation and practical guidance for the design and optimization of MWIS, which is of great significance for the sustainable development of coal mines in the Ordos Basin, China.