Title : Enhanced oil recovery and CO? storage using polymer-enhanced CO? foam: Foam strength and mobility control
Abstract:
Enhanced oil recovery (EOR) and geological CO₂ storage are critical for meeting global energy demands while mitigating climate change. This study investigates the performance of polymer‐enhanced CO₂ foam (PEF) as an advanced method for both EOR and CO₂ sequestration. Conventional CO₂ foams suffer from rapid instability and poor mobility control under harsh reservoir conditions—typically characterized by high temperatures (80 °C) and elevated salinity (~15,000 mg/L). This study investigates the performance of polymer-enhanced CO₂ foam (PEF) for improved mobility control and oil recovery under simulated reservoir conditions. The PEF system was formulated using a 0.1 wt% anionic Alpha Olefin Sulfonate (AOS) surfactant and 0.5 wt% hydrolyzed polyacrylamide (HPAM) in a 4.0 wt% NaCl brine. Core flooding experiments were conducted on four sister core samples with porosities ranging from 17.68% to 20.10% and gas permeabilities between 1.25 and 1.60 mD, at 10 bar and 60°C, maintaining a foam quality of 70%. Results showed that conventional CO₂ foam achieved a recovery factor of 58.0% at an injection rate of 3ft/day (with a maximum differential pressure of 10.39 psi), which increased to 64.5% at 6 ft/day (13.00 psi). In contrast, the polymer-enhanced foam yielded recovery factors of 68.3% and 69.8% at 3 ft/day and 6 ft/day, respectively, with corresponding differential pressures of 10.04 psi and 17.15 psi. These findings underscore the potential of PEF to enhance sweep efficiency and stability in EOR operations while contributing to effective CO₂ sequestration.
Keywords: CO₂ Foam; Enhanced Oil Recovery; Hydrolyzed Polyacrylamide; Foam Stability; Mobility Control; CO₂ Storage
