煤田地质与勘探2026，Vol.54Issue(1)：225-233,9.DOI:10.12363/issn.1001-1986.25.06.0478
水盐环境下蒙脱石纳米孔中CH4与CO2的吸附分布特征及机制探讨
Distribution characteristics and mechanisms of CH4 and CO2 adsorption in montmorillonite nanopores in water-bearing and saline environments
摘要
Abstract
[Background]Carbon capture,utilization,and storage(CCUS)has emerged as a significant way to reduce greenhouse gas emissions under the guidance of the strategic goals of peak carbon dioxide emissions and carbon neutral-ity.With the continuous exploitation of unconventional hydrocarbon resources such as shale oil and gas,varying water-bearing and salinity conditions exert significant impacts on the occurrence stability and seepage behavior of CO2,thereby reducing the efficiency and safety of CO2 storage.Therefore,a thorough understanding of the competitive behavior and distribution patterns of CO2 and other gases in shale nanopores under varying water-bearing and salinity conditions has become a critical scientific issue in the optimization of CO2 storage and flooding processes.[Methods]To reveal the im-pacts of the water-bearing and saline environments on the occurrence and competitive behavior of typical gases,this study constructed slit-shaped nanopore models of montmorillonite under different water-bearing and salinity conditions through molecular dynamics simulations.Accordingly,it systematically analyzed the adsorption configurations,density distributions,diffusion behavior,and variations in interaction energy of CH4 and CO2 under various conditions.[Results and Conclusions]CH4 and CO2 exhibited significant differences in occurrence and migration behavior under dry,water-bearing,and saline conditions.In the dry system,CO2 formed adsorption layers along montmorillonite surfaces,while the density of adsorbed CH4showed a bimodal distribution,with a maximum reaching up to 1.78 g/cm3.After water was added to the dry system,water layers covered the montmorillonite surfaces,weakening gas-mineral interactions.Con-sequently,CO2 and CH4 migrated toward the nanopore center.Upon NaCl addition,CO2 formed secondary adsorption layers at the interfaces,with the peak density of adsorbed CO2 under a NaCl mass fraction of 20％recovering to about 17％of the peak value in the dry system.With an increase in salinity,both CO2 and CH4 displayed decreased self-diffu-sion coefficients,especially CO2,suggesting that CO2diffusion was more significanly restricted.While water films weakened the adsorption potential on the montmorillonite surfaces,Na+enhanced the interfacial re-adsorption of CO2 through electrostatic shielding and hydration clustering.The results of this study reveal the molecular-scale CO2 retain-ment in water-bearing and saline envionments.关键词
非常规油气/水盐环境/分子模拟/CO2/CH4/赋存状态Key words
unconventional oil and gas/water-vearing and saline environments/molecular simulation/CO2/CH4/occur-rence state分类
能源科技引用本文复制引用
都凯,芮振华,钱程,陈思维..水盐环境下蒙脱石纳米孔中CH4与CO2的吸附分布特征及机制探讨[J].煤田地质与勘探,2026,54(1):225-233,9.基金项目
国家重点研发计划项目(2022YFE0206700) （2022YFE0206700）
国家海外引进高层次领军人才支撑项目(2462021YJRC012) （2462021YJRC012）
