Carbon dioxide(CO2) geosequestration in deep saline aquifers has been currently deemed as a preferable and practicable mitigation means for reducing anthropogenic greenhouse gases(GHGs) emissions to the atmosphere, as...Carbon dioxide(CO2) geosequestration in deep saline aquifers has been currently deemed as a preferable and practicable mitigation means for reducing anthropogenic greenhouse gases(GHGs) emissions to the atmosphere, as deep saline aquifers can offer the greatest potential from a capacity point of view. Hence,research on core-scale CO2/brine multiphase migration processes is of great significance for precisely estimating storage efficiency, ensuring storage security, and predicting the long-term effects of the sequestered CO2in subsurface saline aquifers. This review article initially presents a brief description of the essential aspects of CO2subsurface transport and geological trapping mechanisms, and then outlines the state-of-the-art laboratory core flooding experimental apparatus that has been adopted for simulating CO2injection and migration processes in the literature over the past decade. Finally, a summary of the characteristics, components and applications of publicly reported core flooding equipment as well as major research gaps and areas in need of further study are given in relevance to laboratory-scale core flooding experiments in CO2geosequestration under reservoir conditions.展开更多
Precipitation or dissolution due to geochemical reactions has been observed in the caprocks for CO_(2)geosequestration.Geochemical reactions modify the caprock sealing efficiency with self-limiting or self-enhancement...Precipitation or dissolution due to geochemical reactions has been observed in the caprocks for CO_(2)geosequestration.Geochemical reactions modify the caprock sealing efficiency with self-limiting or self-enhancement.However,the effect of this modification on the caprock sealing efficiency has not been fully investigated through multiphysical-geochemical coupling analysis.In this study,a multiphysical-geochemical coupling model was proposed to analyze caprock sealing efficiency.This coupling model considered the full couplings of caprock deformation,two-phase flow,CO_(2)concentration diffusion,geochemical reaction,and CO_(2)sorption.The two-phase flow only occurs in the fracture network and the CO_(2)may partially dissolve into water and diffuse through the concentration difference.The dissolved CO_(2)has geochemical reactions with some critical minerals,thus altering flow channels.The CO_(2)in the fracture network diffuses into matrix,causing the matrix swelling.This fully coupling model was validated with a penetration experiment on a cement cube and compared with two other models for CO_(2)storage plumes.Finally,the effects of geochemical reactions on penetration depth and pore pressure were studied through parametric study.The numerical simulations reveal that the coupling of geochemical reactions and matrix diffusion significantly affect the caprock sealing efficiency.Geochemical reactions occur at a short time after the arrival of CO_(2)concentration and modify the fracture porosity.The CO_(2)diffusion into the matrix requires a much longer time and mainly induces matrix swelling.These effects may produce selfenhancement or self-limiting depending on the flow rate in the fracture network,thus significantly modifying caprock sealing efficiency.展开更多
To reduce the emissions of carbon dioxide(CO) into the atmosphere, it is proposed to inject anthropogenic COinto deep geological formations. Deep un-mineable coalbeds are considered to be possible COrepositories becau...To reduce the emissions of carbon dioxide(CO) into the atmosphere, it is proposed to inject anthropogenic COinto deep geological formations. Deep un-mineable coalbeds are considered to be possible COrepositories because coal is able to adsorb a large amount of COinside its microporous structure.However, the response of coalbeds is complex because of coupled flow and mechanical processes. Injection of COcauses coal to swell, which leads to reductions in permeability and hence makes injection more difficult, and at the same time leads to changes in the mechanical properties which can affect the stress state in the coal and overlying strata. The mechanical properties of coal under storage conditions are of importance when assessing the integrity and safety of the storage scheme. On the other hand, the geomechanical response of coalbed will also influence the reservoir performance of coalbed. This paper provides an overview of processes associated with coalbed geosequestration of COwhile the importance of geomechanical characteristics of coalbeds is highlighted. The most recent findings about the interactions between gas transport and geomechanical characteristics of coal will be discussed and the essence will be delivered. The author suggests areas for future research efforts to further improve the understanding of enhanced coalbed methane(ECBM) and coalbed geosequestration of CO.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.41274111)the financial support of the National Department Public Benefit Research Foundation of MLR,China(Grant No.201211063-4-1)the One Hundred Talent Program of CAS(Grant No.O931061C01)
文摘Carbon dioxide(CO2) geosequestration in deep saline aquifers has been currently deemed as a preferable and practicable mitigation means for reducing anthropogenic greenhouse gases(GHGs) emissions to the atmosphere, as deep saline aquifers can offer the greatest potential from a capacity point of view. Hence,research on core-scale CO2/brine multiphase migration processes is of great significance for precisely estimating storage efficiency, ensuring storage security, and predicting the long-term effects of the sequestered CO2in subsurface saline aquifers. This review article initially presents a brief description of the essential aspects of CO2subsurface transport and geological trapping mechanisms, and then outlines the state-of-the-art laboratory core flooding experimental apparatus that has been adopted for simulating CO2injection and migration processes in the literature over the past decade. Finally, a summary of the characteristics, components and applications of publicly reported core flooding equipment as well as major research gaps and areas in need of further study are given in relevance to laboratory-scale core flooding experiments in CO2geosequestration under reservoir conditions.
基金National Natural Science Foundation of China,Grant/Award Number:51674246Creative Research and Development Group Program of Jiangsu Province,Grant/Award Number:2014-27。
文摘Precipitation or dissolution due to geochemical reactions has been observed in the caprocks for CO_(2)geosequestration.Geochemical reactions modify the caprock sealing efficiency with self-limiting or self-enhancement.However,the effect of this modification on the caprock sealing efficiency has not been fully investigated through multiphysical-geochemical coupling analysis.In this study,a multiphysical-geochemical coupling model was proposed to analyze caprock sealing efficiency.This coupling model considered the full couplings of caprock deformation,two-phase flow,CO_(2)concentration diffusion,geochemical reaction,and CO_(2)sorption.The two-phase flow only occurs in the fracture network and the CO_(2)may partially dissolve into water and diffuse through the concentration difference.The dissolved CO_(2)has geochemical reactions with some critical minerals,thus altering flow channels.The CO_(2)in the fracture network diffuses into matrix,causing the matrix swelling.This fully coupling model was validated with a penetration experiment on a cement cube and compared with two other models for CO_(2)storage plumes.Finally,the effects of geochemical reactions on penetration depth and pore pressure were studied through parametric study.The numerical simulations reveal that the coupling of geochemical reactions and matrix diffusion significantly affect the caprock sealing efficiency.Geochemical reactions occur at a short time after the arrival of CO_(2)concentration and modify the fracture porosity.The CO_(2)diffusion into the matrix requires a much longer time and mainly induces matrix swelling.These effects may produce selfenhancement or self-limiting depending on the flow rate in the fracture network,thus significantly modifying caprock sealing efficiency.
文摘To reduce the emissions of carbon dioxide(CO) into the atmosphere, it is proposed to inject anthropogenic COinto deep geological formations. Deep un-mineable coalbeds are considered to be possible COrepositories because coal is able to adsorb a large amount of COinside its microporous structure.However, the response of coalbeds is complex because of coupled flow and mechanical processes. Injection of COcauses coal to swell, which leads to reductions in permeability and hence makes injection more difficult, and at the same time leads to changes in the mechanical properties which can affect the stress state in the coal and overlying strata. The mechanical properties of coal under storage conditions are of importance when assessing the integrity and safety of the storage scheme. On the other hand, the geomechanical response of coalbed will also influence the reservoir performance of coalbed. This paper provides an overview of processes associated with coalbed geosequestration of COwhile the importance of geomechanical characteristics of coalbeds is highlighted. The most recent findings about the interactions between gas transport and geomechanical characteristics of coal will be discussed and the essence will be delivered. The author suggests areas for future research efforts to further improve the understanding of enhanced coalbed methane(ECBM) and coalbed geosequestration of CO.
