热-流耦合与热-流-固耦合作用下的水气交替及间歇注入对咸水层CO_(2)溶解封存的影响

Impact of Water Alternating Gas and Intermittent Injection on CO_(2)Dissolution During CO_(2)Sequestration in Saline Aquifers Considering Thermal-Hydraulic Coupling and Thermal-Hydraulic-Mechanical Coupling Effects

基于TOUGH+软件架构,结合更为准确的物理性质计算模型,建立了适用于咸水层CO_(2)封存的热-流耦合模拟方法,并使用固定应力分割迭代耦合模型将其与RGMS软件耦合,改进了热-流-固双向耦合模拟方法,建立了准确性更高的热-流-固迭代耦合模拟方法。基于鄂尔多斯盆地地质特征构建的地质模型,使用热-流与热-流-固迭代耦合方法模拟咸水层CO_(2)溶解封存过程,研究了水气交替及间歇注入方案对CO_(2)溶解量、孔隙压力和地层形变的影响。结果表明:热-流-固迭代耦合模拟能帮助设计更加合理的注入方案;仅用水气交替注入方式可提高CO_(2)溶解量;间歇注入有助于孔隙压力与地层形变恢复。研究结果可为咸水层CO_(2)溶解封存提供理论指导。

Based on TOUGH+and a more accurate physical property calculation model,a thermal-hydraulic cou⁃pling simulation method suitable for CO_(2)sequestration in saline aquifers is established.The method was further cou⁃pled with RGMS using the fixed-stress split iteration model,improved from the fixed-stress split two-way model,to obtain a more accurate thermal-hydraulic-mechanical iteratively coupling simulation method.Based on the geo⁃logical characteristics of the Ordos Basin,a geological model is constructed,and the thermal-hydraulic and thermalhydraulic-mechanical coupling simulation methods mentioned above are used to simulate the process of CO_(2)dissolu⁃tion during CO_(2)sequestration in saline aquifers.The impacts of water alternating gas injection and intermittent injec⁃tion schemes on CO_(2)dissolution,pore pressure,and formation deformation are investigated.The following results are found:the thermal-hydraulic-mechanical iteratively coupling model can better assist in designing more reason⁃able injection schemes;only water alternating gas injection can enhance CO_(2)dissolution;intermittent injection con⁃tributes to the recovery of pore pressure and formation deformation.The results can provide theoretical guidance for the CO_(2)sequestration in saline aquifers by CO_(2)dissolution.