Improvement of oil recovery using low oxygen water alternating air injection: A numerical simulation study

As the global energy demand continues to rise, the hydrocarbon industry faces declining production rates from conventional reservoirs, particularly those containing heavy oil. While Enhanced Oil Recovery (EOR) methods remain critical for meeting the growing energy demands, they must align with urgent global goals to reduce carbon emissions and mitigate climate change. This study addresses these challenges by investigating the Water Alternating Low Oxygen Air (LOA) Injection method, using numerical simulations to assess its efficiency and sustainability compared to conventional High-Pressure Air Injection (HPAI). Numerical simulations were conducted on light oil and heavy oil fluid data on homogeneous models and real rock and fluid data in field-scale models to evaluate Water Alternating Air (WAA)’s performance. Key parameters analyzed included cumulative oil recovery, recovery factor (RF), viscosity reduction, and sweep efficiency. The WAA technique leverages Low Temperature Oxidation (LTO) to delay air breakthrough, enhance heat management, and reduce oil viscosity. Simulations showed that WAA increased cumulative oil recovery by up to 257 % in heavy oil reservoirs compared to HPAI. In light oil scenarios, WAA sustained production for over 7300 days without oxygen breakthrough, effectively doubling production time. Field-scale modeling confirmed the method's efficacy in heterogeneous reservoirs, highlighting improved sweep efficiency and prolonged operational periods. By combining low-oxygen air and water injection cycles, WAA offers a scalable, economically viable, and environmentally friendly alternative to conventional air injection. These findings position WAA as a practical EOR solution that balances energy production with the broader imperative of reducing carbon emissions and advancing sustainable energy practices in the hydrocarbon industry.