Geological Storage Potential and Stability of CO2 in Abandoned Deep Coal Seams: A Case Study of the Wanglou Mine, China

This study assesses the CO₂ storage stability and potential of M3 and M4 deep coal seams in the Wanglou closed coal mine in northern Jiangsu, China. Based on eight primary indicators (coal seam cover performance, pressure-to-temperature ratio, depth-to-thickness ratio, groundwater pH value, structural complexity, permeability, degree of collapse in mined-out areas, and other geological factors) and two secondary indicators (fault intensity and density), we applied fuzzy comprehensive evaluation and theoretical modeling. Key findings indicate that the stability scores of the M3 and M4 seams are 86.621 and 89.268, respectively, both classified as “relatively stable.” The theoretical CO₂ storage capacities are 80.842 and 65.439 Mt. Nonminable areas are categorized into favorable, moderately favorable, and unfavorable zones. These outcomes offer crucial theoretical support for site selection in deep coal seam CO₂ geological storage projects, facilitating the green transition of the coal industry by efficiently utilizing abandoned resources.