Geological CO ₂ sequestration is currently one of the main effective pathways to achieve industrial carbon reduction. The adsorption of CO ₂ by coal is a unique storage method for carbon sequestration in underground coal reservoirs. This study conducts isothermal adsorption experiments on high‐rank coal reservoirs with strong gas adsorption capacity in the southeastern part of the Qinshui Basin, exploring the CO ₂ adsorption mechanism, adsorption characteristics, and adsorption capacity of coal reservoirs under different temperature and pressure conditions (especially supercritical conditions). The following conclusions are drawn: (1) The amount of CO ₂ sequestered by coal seams exhibits a negative temperature effect, and the overall trend of adsorption corresponds to the Langmuir adsorption potential; however, under the same temperature and pressure conditions, high‐rank coal has a CO ₂ adsorption capacity 1.5 to 2 times that of CH ₄ . (2) Due to the adsorption characteristics of coal for CO ₂ , various models need to be adopted to simulate adsorption characteristics across different temperature and pressure stages. In subcritical conditions, the single‐layer adsorption theory Langmuir model and the multilayer adsorption characteristic Freundlich model, along with the Tempkin model considering adsorption heat, explain the changes in adsorption characteristics during the CO ₂ adsorption process by coal. In supercritical conditions, an improved D‐R model is used to explain the adsorption mechanism of different pores through micropore‐filling effects. (3) Finally, based on actual geological data and experimental adsorption amounts, the conventional adsorption model or improved D‐R model is applied to predict and assess the CO ₂ sequestration potential of the coal reservoirs in the study area. This study provides theoretical and practical reference significance for understanding the CO ₂ adsorption sequestration characteristics and quantifying sequestration amounts in deep coal reservoirs.

As the effective stress in coal-bearing reservoirs changes, the elastic wave velocities, stress sensitivity, and anisotropic characteristics of coal rocks exhibit certain variations. Therefore, this study selected samples from the same area (sandstone, mudstone, and anthracite) and conducted experiments on their transverse wave velocities (V_s) and longitudinal wave velocities (V_p) and wave velocity ratios in three directions (one perpendicular and two parallel to the layering), using the RTR-2000 testing system under loading pressure conditions. The results indicate that the longitudinal and transverse wave velocities of the coal rock samples show a phase-wise increase with rising pressure. The wave velocities and wave velocity ratios of sandstone, mudstone, and anthracite demonstrate certain anisotropic characteristics, with an overall trend of decreasing anisotropy strength that stabilizes over time. The anisotropic characteristics of the longitudinal wave velocities in sandstone and mudstone are stronger than those of the transverse wave velocities, whereas in anthracite, the anisotropic characteristics of the transverse wave velocities are stronger than those of the longitudinal wave velocities. Thus, it can be concluded that V_p is a sensitive parameter for detecting the anisotropic characteristics of sandstone and mudstone, while V_s serves as a sensitive parameter for detecting the anisotropic characteristics of anthracite.