Geochemical Impacts on CO<sub>2</sub> Storage Efficiency in Deep Aquifers: A Cameroon Gulf of Guinea Case Study

Carbon dioxide (CO 2 ) storage serves as a greenhouse gas mitigation strategy employed by numerous nations. This study aims to explore the feasibility of CO 2 storage in the Rio del Rey Basin, Gulf of Guinea region. We employ a compositional flow model, which has been validated using data from a Subsurface interpretation project in Cameroon.This work is aimed at conducting compositional numerical simulations to investigate the impact of geochemistry on CO 2 aquifer storage. A conceptual development CO 2 storage study has been considered for a deep aquifer reservoir formation Miocene Rio del Rey Basin, Cameroon Gulf of Guinea. The reservoir formations in this basin are set to have very good petrophysical and geological properties for it to be considered as a storage system.The aquifer formation contains various amounts of minerals which in turn would alter the injection of CO 2 as the chemical and geological properties of the storage system change. Some of the chemicals would alter the CO 2 fluid and rock properties and consequently the reservoir injection and storage rates and quantities of injected and stored CO 2 due to minerals precipitation and vaporization phenomena within the storage system. This presents a major concern as the impact of geochemistry on CO 2 injection and storage is not well understood to date which means that the development and operational strategies and costs of such a project are not fully understood and present significant deployment risk and uncertainties.The simulation results show that aquifer geochemistry strongly affects CO 2 brine water storage efficiency at different scales.