Evaluating Storage Potential and Integrity of Depleted Reservoirs for CO₂ Injection

Abstract

As global industrial activity grows, carbon dioxide emissions increase, intensifying greenhouse effect and climate change and demanding solutions beyond renewable energy. This study investigates CO₂ sequestration in subsurface formations as a promising mitigation strategy to support international climate goals and reduce carbon levels. Using CMG 2021 software, different trapping mechanisms, including structural, residual, and solubility trapping, were evaluated in detail to determine their individual and combined contributions to overall storage capacity. Results show that integrating all three mechanisms increases storage potential by 30% compared with structural trapping alone. In addition, geological uncertainty was addressed through Monte Carlo simulations. For that, multiple realizations were generated by varying key reservoir parameters such as porosity, permeability and hysteresis-related parameter. This probabilistic approach allows for a more robust assessment of storage capacity variability and enhances prediction confidence. Furthermore, caprock integrity was evaluated using a two-way geomechanical coupling approach with the Bendis model. The findings indicate that injection-induced pressure reduces effective stresses within the caprock, which may promote tensile failures and create potential leakage pathways. This integrated analysis demonstrates that coupling numerical simulation and probabilistic tools support safer, more effective CO₂ storage, which offers a viable long-term solution for global climate change mitigation efforts.