[H-SC06] CCUS (Carbon Dioxide Capture, Utilization, and Storage) for Climate Mitigation

[HSC06-07] Numerical simulation of CO₂ storage and CO₂ leakage along the fault during CO₂ geo-sequestration in saline aquifer using THMC software

*Huy Gia Lam ¹, Jui-Sheng Chen^1,2 (1.Graduate Institute of Applied Geology, National Central University, Taoyuan, Taiwan, 2.Center for Advanced Model Research Development and Application, National Central University, Taoyuan, Taiwan)

Keywords: CO2 geo-sequestration, THMC, CO2 movement, CO2 leakage, Fault

The urgency of addressing climate change is emphasized by the global carbon challenge, highlighting CO₂ geo-sequestration in saline aquifers as a key strategy for carbon capture and storage (CCS). However, many studies have yet to fully investigate the roles of CO₂ and brine densities, as well as the effects of density differences between CO₂ and brine and permeability differences between the caprock and saline aquifer on storage performance. Additionally, leakage risk remains a critical challenge, requiring accurate predictions to ensure storage site safety and efficiency. This study employs the THMC model, developed by the Center for Advanced Model Research Development and Application at National Central University, to simulate the complex interactions of thermo-hydro-mechanical-chemical (T-H-M-C) processes in underground CO₂ storage, focusing on CO₂ migration and stabilization under varying density and caprock permeability conditions while assessing potential leakage along faults. The findings indicate that CO₂ density significantly influences plume behavior, where low-density CO₂ with a high-density difference from brine rises rapidly due to buoyancy, increasing leakage risks, whereas high-density CO₂ with a lower density difference exhibits greater stability, reducing vertical migration. Furthermore, the results demonstrate that the THMC model effectively simulates CO₂ storage in deep saline aquifers, identifies potential leakage pathways, and provides insights for improving storage system safety and stability over a one-year injection period.