| 摘要 |
--A method for recovering viscous oil from a subterranean, viscous oil-containing formation underlain by a water zone. Steam is injected into the formation via the injection well at the oil/water contact and oil is recovered from the formation until steam breakthrough occurs at the production well thereby forming a hot plate at the oil/water contact. Thereafter, the production well is shut-in and a combustion-supporting gas, preferably pure oxygen, is injected into the formation at the oil/water contact causing an in-situ combustion reaction to occu at the oil/water contact and pressurization of the formation. Injection of the combustion-supporting gas is continued until th formation is pressurized to a specific pressure not to exceed th pressure at which fracture of the overburden above the formation would occur. Thereafter, the injection well is shut-in and oil is recovered from the formation via the production well. If desired, after injection of the combustion-supporting gas is discontinued, the formation may be subjected to a soak period by shutting-in the injection and production wells for a time sufficient to allow the injected combustion-supporting gas to be consumed in the in-situ combustion reaction.
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