CO_2 long-term diffusive leakage into biosphere in geological carbon storage  

作　　者：Qin-Yi Li Qun Chen Xing Zhang 

机构地区：[1]Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Engineering Mechanics,Tsinghua University

出　　处：《Chinese Science Bulletin》2014年第28期3686-3690,共5页

基　　金：supported by the National Natural Science Foundation of China (51006060, 51136001);the Tsinghua University Initiative Scientific Research Program

摘　　要：Prediction of CO2 leakage into biosphere is very important for risk assessment in geological carbon storage projects. Underground CO2 can be transported into biosphere through short term leakage due to fractures of wellbores or cap rocks, which has been extensively investigated, and long term leakage due to diffusion, which has few relevant studies. This paper presents a diffusive model for CO2 gradual leakage into biosphere during a long period after CO2 injection. First, the paper describes a general diffusive model with long term secondary trapping effects for CO2 fluxes from underground into biosphere. Secondly, a simplified one-dimensional model is presented and solved for the CO2 concentrations in groundwater. The results show that the groundwater CO2 concentration will reach the maximum value at about 50 th year after CO2 injection and then slowly decrease due to secondary trapping effects.Moreover, the partition coefficient is the dominant parameter for predicting the groundwater CO2 concentration while the convective mass transfer coefficient plays an insignificant role.Prediction of CO2 leakage into biosphere is very important for risk assessment in geological carbon storage projects. Underground CO2 can be transported into bio- sphere through short term leakage due to fractures of wellbores or cap rocks, which has been extensively investi- gated, and long term leakage due to diffusion, which has few relevant studies. This paper presents a diffusive model for CO2 gradual leakage into biosphere during a long period after CO2 injection. First, the paper describes a general dif- fusive model with long term secondary trapping effects for C02 fluxes from underground into biosphere. Secondly, a simplified one-dimensional model is presented and solved for the CO2 concentrations in groundwater. The results show that the groundwater CO2 concentration will reach the maximum value at about 50th year after CO2 injection and then slowly decrease due to secondary trapping effects. Moreover, the partition coefficient is the dominant parameter for predicting the groundwater CO2 concentration while the convective mass transfer coefficient plays an insignificant role.

关 键 词：CO2浓度 扩散模型 生物圈 碳储存 泄漏 地质 二氧化碳浓度 质量传递系数 

分 类 号：TD84[矿业工程—煤矿开采]