The low wettability and poor permeability of deep coal seams limit the efficacy of conventional water injection for gas recovery. Here, we report an acidic ZnO/SDBS nanofluid system that simultaneously modifies coal surface chemistry and pore structure through an integrated interfacial engineering approach. Under optimized conditions (1.0 wt % ZnO, 0.15 wt % SDBS, pH = 3), the nanofluid reduces the coal contact angle to 27.9°, enhances wettability by 67.4%, and increases total pore volume by 41.3% while reducing specific surface area. These changes promote competitive water adsorption, suppress methane adsorption, and improve gas transport pathways. The results demonstrate a scalable, chemical-based process intensification strategy for enhancing coal seam methane extraction, with potential applications in other subsurface resource recovery operations involving low-permeability porous media.
Liu et al. (Thu,) studied this question.