Spatiotemporal Impact of CO₂ Injection Rates on Plume Dynamics and Fault Reactivation in Geological Reservoirs: Insights from Numerical Simulation

Climate change remains one of the most pressing global challenges of the 21st century. The urgent need to mitigate climate change has brought carbon dioxide (CO2) sequestration into focus as a critical strategy for reducing atmospheric CO2 concentrations. This study examines the spatiotemporal impacts of varying CO2 injection rates (5, 10, and 15 kg/s) on plume dynamics and fault reactivation in faulted geological reservoirs through numerical simulations using COMSOL Multiphysics. The results demonstrate that higher injection rates enhance CO2 sequestration (191,738.88 tons at 15 kg/s) but reduce storage efficiency, with the 5 kg/s rate yielding the highest efficiency (0.073 tons/second). Increased injection rates also result in rapid pressure buildup, which poses significant risks to caprock integrity. CO2 plume migration becomes more pronounced at higher injection rates, particularly toward fault zones, leading to an elevated risk of fault reactivation (47% at 15 kg/s). These findings highlight the critical need to carefully balance injection rates in order to optimize storage capacity while minimizing safety risks in CO2 sequestration operations.