CO2 storage in coal seams has become one effective method to reduce CO2 emission and help exploit coalbed methane (CBM). The permeability is a key parameter for CBM extraction. In deep coal seams (>800 m), CO2 exists in the supercritical state. In the present work, permeability tests were performed on briquettes before and after supercritical CO2 (SC-CO2) adsorption at various temperatures to investigate the effects of SC-CO2 adsorption on the permeability. Experimental results show that SC-CO2 adsorption leads to volumetric expansion and permeability augment. The permeability enhancement decreases continuously at 35°C, while it initially increases and reduces at pressures exceeding 9 or 10 MPa at 45 or 55°C, respectively. Besides, the permeability enhancement ratio shows a linear increase with the expansion. The research provides a basis for further research on the enhanced coalbed methane (ECBM) recovery.

中文翻译：

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不同温度下超临界CO2吸附后煤的渗透特性

在煤层中封存二氧化碳已成为减少二氧化碳排放和帮助开发煤层气（CBM）的一种有效方法。渗透率是煤层气开采的关键参数。在深层煤层（>800 m）中，CO2 以超临界状态存在。在目前的工作中，在不同温度下对超临界 CO2 (SC-CO2) 吸附前后的煤球进行渗透率测试，以研究 SC-CO2 吸附对渗透率的影响。实验结果表明，SC-CO2 吸附导致体积膨胀和渗透率增加。渗透率增强在 35°C 时持续降低，而在 45°C 或 55°C 时分别在超过 9 或 10 MPa 的压力下开始增加和减小。此外，渗透率增强率随着膨胀呈线性增加。