METHOD OF RECOVERING OIL USING CONTINUOUS STEAM FLOOD FROM A SINGLE VERTICAL WELLBORNE

摘要

A method for recovery of oil from a subterranean, viscous oil-containing formation penetrated by one or more wells each of which is provided with at least two separate flow paths, the first flow path in fluid communication with the bottom of the formation from adjacent or below the formation and the second flow path in fluid communication with substantially the full vertical thickness of the formation. Steam is injected into the formation via the second flow path and fluids including oil are recovered from adjacent or below the bottom of the formation via the first flow path at a predetermined rate which is substantially less than the injection rate of steam so as to increase the formation pressure to a desired level. Formation pressure is maintained at the desired level while continuing injection of steam and production of fluids including oil until the fluids recovered contain an unfavorable amount of water. In a preferred embodiment, the tubing providing the first flow path may be progressively withdrawn or lowered into the wellbore to obtain improved steam-oil ratios and/or higher oil production rates. This method provides maximum gravity drive displacement of oil from the formation.