Hydro-mechanical coupling analysis of carbon dioxide migration in saline aquifers

Carbon capture and storage (CCS) is a critical strategy for reducing atmospheric CO₂ and achieving global net-zero targets. This study presents a coupled hydro-mechanical finite element analysis of CO₂ injection in saline aquifers. A benchmark model with two aquifers and a sealing caprock was validated through comparison with established results, showing consistency in saturation, pressure, and leakage behavior. To improve realism, geological parameters reflecting natural conditions were intergrated. Sensitivity analyses assessed the effects of injection rate and permeability on caprock stability. Results indicate that higher injection rates increase pore pressure heterogeneity and shear strain. A critical threshold between 3.08 and 3.50 Mt/yr was identified, beyond which deformation intensifies. However, no structural failure occurred, as the damage factor remained below critical levels. These findings demonstrate the robustness of the coupled modeling approach and offer insights into the geomechanical response of saline formations under high-rate CO₂ injection.