Oil recovery - from underground reservoirs by alternating gas propulsion and water injection

摘要

Oil is recovered from a reservoir with is not 1 injection boring and is not 1 prodn. boring by (a) recovering oil through the prodn. boring by propulsion by a gas in soln., while the press. drops to a point below that of bubble-formation, but within the critical gas satn. of the reservoir at the press. existing in the reservoir, (b) stopping the gas propulsion and injecting water via the injection boring, while maintaining the existing press. in the reservoir and at the same time recovering oil from the reservoir through the prodn. boring to a point where the rate of oil prodn. has reached a particular end point (c) stopping water injection and producing oil from the reservoir through the prodn. boring by propulsion of the gas in soln., while the press. drops to below the point of bubble-formation but within the critical gas satn. of the reservoir at the press. then existing in the reservoir, (d) stopping the gas propulsion and injecting water through the injection boring and at the same time producing oil from the reservoir through the prodn. boring to a point at which the rate of oil prodn. has reached a particular end-point, and (e) repeating steps (a) and (b) until the end-press. of the reservoir has been reached. Increased prodn. is achieved.