OPTIMIZATION OF CO₂ INJECTION FOR ENHANCED OIL RECOVERY AND GEOSTORAGE IN TIGHT SANDSTONE OIL RESERVOIR OF THE NIGER DELTA BASIN

The growing need for sustainable petroleum production and greenhouse gas reduction has driven interest in carbon dioxide (CO₂)-based Enhanced Oil Recovery (EOR) as a dual-purpose technology for increasing oil recovery while enabling carbon sequestration. This study investigates the potential of CO₂ injection for enhanced oil recovery and geo-storage in tight sandstone reservoirs within the Niger Delta Basin, Nigeria. Laboratory-based simulations and analytical modeling were used to evaluate the influence of injection rate, permeability, wettability, and fracture dip angle on oil displacement efficiency and CO₂ storage performance. Results show that at lower injection rates (0.2 mL/min), delayed breakthrough (0.85 PV) was observed with a recovery factor of 88.2%, while moderate rates (0.5 mL/min) achieved optimal recovery (91.4%) and balanced CO₂ retention (58.1%). Higher rates (1.0 mL/min) led to early breakthrough (0.55 PV) and reduced storage efficiency (54.9%). Overall, findings demonstrate that CO₂ injection enhances oil recovery by 85–93% and achieves up to 65% storage efficiency, depending on reservoir conditions. The study confirms that CO₂-EOR is technically feasible for the Niger Delta Basin, offering both economic and environmental benefits by improving hydrocarbon recovery and reducing carbon emissions.