EFFECTIVENESS OF CO2-WAG INJECTION FOR ENHANCED OIL RECOVERY IN CARBONATES RESERVOIR: A SIMULATION STUDY

Abstract

This study evaluates the effectiveness of CO2-WAG injection in enhancing oil production and recovery factor (RF) in carbonate reservoirs, considering CO2 and water injection rates and CO2 breakthrough. A compositional sectoral reservoir model was used for numerical simulation and detailed reservoir model development based on contour map digitalization and logging data. The research scenarios included variations in CO2 and water injection rates, WAG ratios, and comparisons between CO2-WAG, CO2 Slug and Continuous CO2 injection to assess RF and CO2 breakthrough. The results demonstrate a positive linear relationship between injection rates and oil production and RF in CO2-WAG injection, with increases in CO2 and water injection rates up to 35,000 MMSCFD and 2,500 BWPD proving effective in enhancing RF. A 2:1 WAG ratio achieved a 66.2% RF and delayed CO2 breakthrough by 69 days compared to Continuous CO2 injection. The findings suggest that CO2-WAG injection with a 2:1 WAG ratio can be an effective field development strategy for increasing oil production and RF while reducing CO2 emissions.