The purpose of this study was to develop a method for evaluating the risk of CO2 leakage, and to study the effects of complex bedded sandstone-shale sequences of a storage formation on the risk of CO2 leakage by using the case of a deep saline aquifer CO2 sequestration demonstration project in Taiwan. The risk of CO2 leakage for any kind of storage site with or without complex lithology was evaluated using the safety index (SFI), which was defined in this study and calculated from the combined contributions of all of the safe trapping mechanisms. The risk of CO2 leakage quantitatively evaluated using the SFI was dynamic over the span of CO2 storage time.The engineering strategies of maximizing the contributions of the safe trapping mechanisms can lower the risk of CO2 leakage in a storage formation with complex bedded sandstone-shale sequences by choosing an appropriate well location based on the SFI. The presence of Fe/Mg minerals lowers the risk of CO2 leakage. The transmissibility of the injection layer was not a mitigating factor for the risk of CO2 leakage. For the risk assessment of any kind of CO2 storage formation with or without complex lithologies, the best scenario should be decided based on the estimation of the SFI, which is the standard criterion used in this study.
All Science Journal Classification (ASJC) codes
- Industrial and Manufacturing Engineering
- Management, Monitoring, Policy and Law