Experimental investigation of steam‐CO 2 ‐foam flooding: combination of CO 2 ‐foam flooding and steam injection as an effective enhanced oil recovery (EOR) method in heavy oil reservoirs

The effects of steam‐CO 2 ‐foam flooding on the recovery of medium–heavy crude oil have been studied using sand pack models under reservoir conditions of 1550 psi and 131 °F. In order to investigate the enhanced oil recovery (EOR) potential of steam‐CO 2 ‐foam flooding, three different types of oil recovery experiments including CO 2 ‐foam flooding, CO 2 ‐foam flooding after water flooding, and steam‐CO 2 ‐foam flooding have been conducted. Experiments for the first two cases were conducted using 1.3 PV injection of CO 2 ‐foam. In the other case, 0.3 PV of steam injection was followed by 1 PV of CO 2 ‐foam flooding. The ultimate oil recovery values obtained using the first two scenarios have been 57.5 and 41.21, respectively, indicating that applying CO 2 ‐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‐CO 2 ‐foam flooding improves oil recovery with lower pore volume of the injected CO 2 ‐foam. The effect of high surfactant concentration slug injection on the steam‐CO 2 ‐foam flooding performance has also been investigated. The ultimate oil recovery obtained using slug with a high concentration of surfactant solution (0.75 wt%) and CO 2 has been 83.88% which shows that slug increases foam stability and improves CO 2 ‐foam sweep efficiency. © 2015 Curtin University of Technology and John Wiley & Sons, Ltd.