Experimental investigation of steam-CO2-foam flooding: combination of CO2-foam flooding and steam injection as an effective enhanced oil recovery (EOR) method in heavy oil reservoirs

The effects of steam-CO2-foam flooding on the recovery of medium-heavy crude oil have been studied using sand pack models under reservoir conditions of 1550psi and 131 degrees F. In order to investigate the enhanced oil recovery (EOR) potential of steam-CO2-foam flooding, three different types of oil recovery experiments including CO2-foam flooding, CO2-foam flooding after water flooding, and steam-CO2-foam flooding have been conducted. Experiments for the first two cases were conducted using 1.3 PV injection of CO2-foam. In the other case, 0.3 PV of steam injection was followed by 1 PV of CO2-foam flooding. The ultimate oil recovery values obtained using the first two scenarios have been 57.5 and 41.21, respectively, indicating that applying CO2-foam flooding as a tertiary EOR method after water flooding is not favorable. The ultimate oil recovery obtained during the third scenario has been 75.64%, which clearly shows that steam-CO2-foam flooding improves oil recovery with lower pore volume of the injected CO2-foam. The effect of high surfactant concentration slug injection on the steam-CO2-foam flooding performance has also been investigated. The ultimate oil recovery obtained using slug with a high concentration of surfactant solution (0.75wt%) and CO2 has been 83.88% which shows that slug increases foam stability and improves CO2-foam sweep efficiency. (c) 2015 Curtin University of Technology and John Wiley & Sons, Ltd.