A multiphysical-geochemical coupling model for caprock sealing efficiency in CO_(2) geosequestration  

作　　者：Jianguo Wang Huimin Wang Xiaolin Wang Shengqi Yang Hongtao Wu Chunfai Leung Jiali Tian 

机构地区：[1]School of Mechanics and Civil Engineering,China University of Mining and Technology,Xuzhou,China [2]State Key Laboratory for Geomechanics and Deep Underground Engineering,China University of Mining and Technology,Xuzhou,China [3]College of Water Conservancy and Hydropower Engineering,Hohai University,Nanjing,China [4]School of Engineering,University of Tasmania,Hobart,Tasmania,Australia [5]Center for Offshore Research and Engineering,National University of Singapore,Singapore,Singapore

出　　处：《Deep Underground Science and Engineering》2023年第2期188-203,共16页深地科学（英文）

基　　金：National Natural Science Foundation of China,Grant/Award Number:51674246;Creative Research and Development Group Program of Jiangsu Province,Grant/Award Number:2014-27。

摘　　要：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.

关 键 词：caprock sealing efficiency CO_(2)diffusion CO_(2)geosequestration geochemical reaction sorption strain 

分 类 号：P3[天文地球—地球物理学]