A Numerical Comparative Analysis of Gas and Foam Injection for Carbon Utilization and Storage in a Depleted Oil Formation

Abstract Carbon Capture, Utilization, and Storage (CCUS) strategies are increasingly important for reducing carbon emissions in the petroleum industry. Foam injection has emerged as a promising technique that not only enhances oil recovery but also improves CO2 storage capacity. In this study, we investigated the effectiveness of CO2 foam injection for simultaneously optimizing oil recovery and CO2 storage in a depleted oil reservoir. A hydrodynamic model was simulated to represent a formation with 30% residual oil, incorporating three CO2 trapping mechanisms: solubility, residual, and mineralization trapping. The findings reveal that foam injection resulted in oil recovery rates more than twice as high as those achieved with gas injection. Foam injection also improved CO2 retention, with almost 30% of injected CO2 remaining in the reservoir after 20 years, compared to 25% with gas injection. The theoretical CO2 storage capacity was enhanced by 2.3 times, potentially storing up to 1.72 gigatons of CO2 in the model. Residual trapping was the primary mechanism responsible for this increased storage, while solubility trapping was constrained by high brine salinity. This study demonstrates that CO2 foam injection can significantly improve both CO2 sequestration and oil recovery in depleted oil reservoirs, offering a dual benefit for CO2 injection in the petroleum industry.