煤田地质与勘探2026，Vol.54Issue(1)：142-157,16.DOI:10.12363/issn.1001-1986.25.07.0572
ScCO2-水作用下页岩纳米孔与吸附性能演变机制
Evolutionary mechanisms of nanopores and adsorption capacity in shales under ScCO2-water-rock interactions
摘要
Abstract
[Background]Supercritical carbon dioxide(ScCO2)-enhanced shale oil and gas recovery serves as an effect-ive approach to geologic CO2 sequestration.Injecting ScCO2 into shale reservoirs can trigger complex ScCO2-water-rock interactions,thereby altering the material composition,nanopore structure,and adsorption capacity of shales.Examining their evolutionary processes represents a critical scientific issue in the evaluation of CO2 sequestration efficiency.[Meth-ods]This study investigated the shales of the Longmaxi Formation in the southeastern Chongqing area.Through simula-tion experiments on ScCO2-water-rock interactions and by integrating X-ray diffraction(XRD),low-pressure CO2/N2 ad-sorption,fractal theory,and isothermal adsorption experiments,this study explored the evolution mechanisms behind the material composition,nanopore structure,fractal heterogeneity,and adsorption capacity of shales under ScCO2-water-rock interactions.By controlling the time,temperature,and pressure of ScCO2-water-rock interactions,this study con-ducted in-depth analyses of factors affecting CO2 adsorption and sequestration efficiency.[Results and Conclusions]The ScCO2-water-rock interactions consisted primarily of organic matter extraction and dissolution,mineral dissolution,and ion-exchange reactions,which significantly reduced the mass fractions of the total organic carbon(TOC),carbon-ates,and clay minerals in shales.With an increase in the reaction time and pressure,the mass fractions of the organic and inorganic components in shales varied more significantly.Organic matter extraction and mineral dissolution led to in-creases in the volume and specific surface area of nanopores in shales.Elevated temperature primarily promoted the de-velopment of micropores measuring 0.9-1.5 nm in size.In contrast,a rise in pressure led to a significant increase in the volumes of both micropores(＜2 nm)and mesopores(2-50 nm)while also enhancing the heterogeneity of pore struc-tures.However,as the reaction time increased,secondary minerals precipitated and blocked pores.Notably,micropores and their heterogeneity were particularly susceptible to precipitation-induced volume reduction.Compared to subcritical temperature and pressure conditions,shales after CO2-water-rock interactions exhibited a surge in CO2 adsorption capa-city and rate under supercritical conditions.Therefore,maintaining the temperature and pressure conditions for ScCO2 is crucial to improvements in the CO2 adsorption capacity and sequestration efficiency of shale reservoirs.Notably,in the long-term CO2 sequestration process,the degradation of storage efficiency induced by secondary mineral precipitation-associated pore blocking warrants more attention.Overall,the results of this study provide a theoretical foundation for both the application of ScCO2-enhanced shale oil and gas recovery and the scientific optimization of geologic CO2 se-questration efficiency.关键词
超临界CO2/页岩/孔隙结构/分形/吸附/溶蚀/沉淀Key words
supercritical carbon dioxide(ScCO2)/shale/pore structure/fractal/adsorption/dissolution/precipitation分类
天文与地球科学引用本文复制引用
冯光俊,王猛,朱炎铭,宋昱,代旭光,郑司建,谢红,尚福华..ScCO2-水作用下页岩纳米孔与吸附性能演变机制[J].煤田地质与勘探,2026,54(1):142-157,16.基金项目
国家重点研发计划项目(2024YFC2909400) （2024YFC2909400）
国家自然科学基金项目(42202190,42402177) （42202190,42402177）
江苏省自然科学基金项目(BK20221147) （BK20221147）
国家资助博士后研究人员计划项目(GZC20233002) （GZC20233002）
