关闭煤矿煤层CO₂地质封存是CO₂封存的重要方式之一，也是短期内实现碳减排指标的有效手段之一。以江苏省徐州市三河尖关闭煤矿为例，分析了已采7号煤和9号煤的煤岩煤质特征，统计了剩余煤炭资源储量，运用模糊综合评价法，选取了稳定系数、上覆岩层性质、地质构造复杂程度、地下水指标、封存煤层压温比、封存煤层深厚比、封存煤层渗透率、采空塌陷程度和其他因素等9个主要影响因素指标对7号煤和9号煤封存CO₂稳定性进行评价，建立关闭煤矿煤层CO₂封存评价方法并评估CO₂封存潜力。结果表明，三河尖关闭煤矿7号煤和9号煤剩余储量较大，CO₂封存稳定性综合评价结果分别为86.209和87.698，评价等级均为较稳定，封存潜力较高。根据建立的关闭煤矿煤层CO₂封存评价方法，计算获得三河尖关闭煤矿7号和9号煤层CO₂理论封存量分别为207.6 Mt和80.9 Mt，并据此划分封存有利区为有利区、较有利区和不利区3个等级。研究可为关闭煤矿煤层CO₂封存研究提供基础依据。

Geological sequestration of CO₂ in closed coal mines' coal seams is a significant method for CO₂ sequestration and an effective strategy to achieve short-term carbon emission reduction goals. This study focuses on the Sanhejian coal mine in Xuzhou City, Jiangsu Province. The study scrutinizes the features of the coal rock and the quality of the mined No. 7 and No. 9 coal seams. Additionally, it calculates the remaining coal resource reserves. The study also applies the fuzzy comprehensive evaluation method to identify nine main influencing factors for the CO₂ storage stability of the No. 7 and No. 9 coals. These factors include the stability factor, the nature of the overlying rock strata, the complexity of the geotectonic structure, the index of groundwater, the ratio of the sealed coal bed pressure to temperature, the ratio of the sealed coal bed depth to depth, the permeability of sealed coal beds, the degree of the hollowing-out collapse, and other relevant factors. We assessed the stability of CO₂ storage in No. 7 and No. 9 coals based on key influencing elements. We developed a CO₂ storage evaluation method to assess the CO₂ storage capacity of coal seams in sealed coal mines. The findings indicate that the remaining reserves of No. 7 coal and No. 9 coal in the Sanhejian closed coal mine are substantial. The comprehensive evaluation results for CO₂ storage stability are 86.209 and 87.698, respectively, indicating a higher level of stability and greater potential for storage. The CO₂ storage capacity of the No. 7 and No. 9 coal seams in the closed coal mines of Sanhejian was determined using the established evaluation method. We calculated the theoretical storage capacity to be 207.6 Mt and 80.9 Mt, respectively. This led to the division of the storage area into three levels: favorable, more favorable, and unfavorable. The work can establish a fundamental foundation for investigating the storage of CO₂ in coal seams within decommissioned coal mines.