Assessing the efficiency of long-term CO₂ geological storage using an advanced multiphase compositional simulator

CO2 sequestration has a critical role in mitigating climate change impacts, thus we rely on numerical simulations to capture the processes of CO2 injection, migration, and long-term storage. This paper presents a comprehensive benchmarking study of an in-house built multiphase compositional simulator for CO2 storage modelling applications, emphasizing the accurate modeling of trapping mechanisms within geological formations. We perform rigorous tests to benchmark the simulator's performance against established analytical solutions, focusing on the evolution of CO2 plumes, leakage rates through abandoned wells, and interactions of CO2 with the formation water. Our results demonstrate the simulator's robustness in handling complex subsurface phenomena, including variable property simulations and the effects of hysteresis on plume behavior. These comparisons offer insights into the effects of parameter choices and boundary conditions on the simulation outcomes. Our work not only validates the simulator against known analytical solutions and numerical benchmarks, but also lays a foundation for future enhancements in our code, particularly in the area of geochemical interactions and the assessment of CO2 leakage on the security of the storage media. (c) 2026 Southwest Petroleum University. Publishing services by Elsevier B.V. on behalf of KeAi Communications Co. Ltd. This is an open access article under the CC BY-NC-ND license (http:// creativecommons.org/licenses/by-nc-nd/4.0/).