Combined Cyclic Solvent Injection and Waterflooding in the Post-Cold Heavy Oil Production with Sand Reservoirs

In this paper, cyclic solvent injection (CSI) and waterflooding (WF) were combined and studied to maximize their technical synergy and optimize the enhanced heavy oil recovery (EHOR) in the post-cold heavy oil production with sand (CHOPS) reservoirs. The original heavy oil sample was collected from the Colony formation in western Canada. The PVT data and viscosities of CH4/CO2/C3H8-saturated heavy oil were measured at different equilibrium pressures and Tres = 21 °C. A total of eight sandpacked laboratory tests were conducted to study and compare four different EHOR processes after the primary production: CSI, CSI + WF, simultaneous CSI + WF, and WF + CSI. In the last three processes, WF was applied after, simultaneously with, and prior to the CSI production, respectively. Three different pressure drawdown rates (6.8, 12.5, and 25.0 kPa/min) and two different solvents (CO2 and C3H8) were used to determine their specific effects on CSI + WF. The experimental results showed that CSI + WF had the highest hea...