Carbon Capture Optimisation for a Greener Tomorrow Using a Proxy Model-Driven Numerical Simulation

Abstract As the urgency to combat climate change grows, the role of Carbon Capture, Utilization, and Storage (CCUS) in mitigating greenhouse gas emissions becomes increasingly pivotal for a more sustainable oil industry. However, the entrapment of CO2 in depleted reservoirs faces a significant challenge—cap rock integrity failure leading to CO2 leakages into surrounding aquifers. Previous studies have predominantly focused on CO2 storage modeling, neglecting optimization strategies that reduce leakage risks and how such optimization may impact storage performance. Consequently, limited knowledge exists on rock property sensitivity to cap rock leakage. This study centres on coupling flow-geomechanics simulation with proxy modeling to optimize CO2 storage and minimize leakage. A reservoir slab with varying permeability was modelled to investigate the efficiency of structural, stratigraphic, and residual trapping mechanisms. Incorporating a structural trapping mechanism alone resulted in 19.84% of CO2 entrapment. However, residual trapping contributed to 78.71% and solubility trapping led to 60.98% entrapment. The Barton-Bandis model was utilized to simulate cap rock integrity failure a sensitivity analysis was conducted. From this analysis, CO2 leakage through cap rock is mostly influenced by fracture-effective stress. Hence, there is a need to always monitor injection pressure since it can increase stress. The presence of a cap rock is integral to preventing the migration of captured CO2.