Coupled Thermal-Hydrodynamic-Chemical-Mechanical Processes Modeling for Caprock Integrity in CO2 Geological Storage
Seminar
Coupled thermal (T)–hydrodynamic (H)–chemical (C)–mechanical (M) processes have become increasingly important in studying the issues affecting subsurface flow systems, such as CO2 storage in deep geological formations. In this study, a mechanical module based on the extended Biot3D consolidation model was developed and incorporated into the well-established thermal–hydrodynamic-chemical simulator - TOUGHREACT, resulting in an integrated numerical THCM simulation program. The finite element method was employed to discretize space for rock mechanical calculation, and the Mohr-Coulomb failure criterion was used to determine whether the rock undergoes shear-slip failure. The program was applied to evaluate the thermal, hydrodynamic, chemical, and mechanical responses of CO2 geological storage at the Ordos CCS (CO2 Capture and Storage) Demonstration Project, China. The results demonstrate that the CO2-induced mineral reactions, specifically the CO2-water-rock interaction, has significant impact on the hydrogeological and mechanical properties of porous media, thereby changing their integrity and mechanical characteristics. The modeling tool developed could be very useful for evaluation of the storage capacity and safety of CO2 geological storage projects.
Tianfu Xu is currently a professor at Jilin University of China. He has been working at Lawrence Berkeley National Laboratory (LBNL) of USA for 16 years, in which he joined in 1996, initially as post-doctoral fellow, then become a scientist, and staff scientist. He received a bachelor’s degree in 1984 from Jilin University, an M.S. degree in 1993 from Delft University of Technology of The Netherlands, and a Ph.D. in 1996 from University of La Coruña, Spain. For the last 3 years, Tianfu has been working on developing new approaches to modeling multiphase non-isothermal fluid flow and chemical transport in unsaturated and saturated porous media and fractured rock systems. He is the chief developer of LBNL’s multi-phase non-isothermal reactive flow and chemical transport simulator TOUGHREACT. The program is widely used nationally and internationally for CO2 geological sequestration, geothermal energy development, nuclear waste disposal, environmental remediation, and increasingly for petroleum applications. Tianfu has authored and co-authored about 160 peer-reviewed journal papers. His papers have been cited by other researchers more than 8000 times (SCI citation).