Application of Vapor Extraction (Vapex) Process in High Pressure Heavy Oil Reservoirs Using Mixed Gases

Vapor Extraction (Vapex) process is a relatively new process for heavy oil recovery which uses vaporized solvents to enhance the production by decreasing the viscosity of oil. In reservoirs with high pressure conditions, like Kuh-e-Mund reservoir in Iran, pure vaporized solvents can not be used as they will condense which results in decreasing the efficiency and increasing the cost of the process. In this case the solvent should be accompanied by a non-condensable gas as carrier gas to prevent condensation. This experimental work investigates the applicability of Vapex process in an Iranian heavy oil reservoir with high viscosity and high reservoir pressure, using mixed gases. The experiments are performed at 200 and 400 psig pressures with propane as solvent and methane and carbon dioxide as non-condensable carrier gases. It can concluded from these results that using mixed gases in general lowers the overall recovery of the process compared with the previous results obtained using pure solvents. But in this case the recovery is a strong function of concentration of solvent in the gas mixture and also the properties of carrier gas.

Keywords:

Vapex Process , Heavy Oil , High Pressure , Non-condensable Gas , Mixed Gas , Hydrocarbon Solvent , Experimental Investigation