SUNDAY AGBONS IGBINERE.

This research focuses on modeling and simulating CO₂ injection and storage in a depleted sandstone reservoir using the CMG-GEM compositional simulator to evaluate the potential of geological carbon sequestration as a sustainable emission reduction strategy. A 3D reservoir model was constructed based on available structural and petrophysical data to replicate the dynamic behavior of CO₂ during and after injection. The simulation was performed under varying pressure and compositional conditions to assess injectivity, storage capacity, and reservoir response over a 69-year period. Results revealed effective CO₂ migration through the formation, with plume dispersion influenced by permeability variations across the ten layers. The estimated total CO₂ storage capacity of the reservoir was approximately 136,863 tonnes, indicating substantial potential for long-term containment. Pressure analysis showed a gradual and controlled buildup within safe limits, confirming caprock stability and the absence of leakage or fracture risk. Additionally, the molality plots demonstrated consistent distribution of CO₂ within the formation, with concentration stabilization after a five-year halt and resumption of injection in 2050, reflecting strong reservoir retention. Overall, the study confirms that the selected depleted reservoir can serve as a viable site for CO₂ sequestration. The findings also highlight the importance of optimizing well placement, incorporating residual and mineral trapping mechanisms, and extending simulation timeframes to improve prediction accuracy and long-term storage performance.