VISCOUS OIL RECOVERY METHOD

摘要

VISCOUS OIL RECOVERY METHOD Our invention concerns a method for treating a well completed in a subterranean petroleum containing formation which will improve the rate at which steam can be injected into the formation for a steam push-pull or steam drive oil recovery method. This preconditioning process is applied to formations exhibiting very limited steam receptivity because the formation contains high oil viscosity and has high oil saturation and is completely liquid filled. The method involves injecting a heated non-condensable and oil soluble gas all in the gaseous phase into the formation at a controlled rate which will avoid permanently fracturing the formation and also avoid the immediate formation of an oil bank due to dissolution of the injected gaseous fluid into the oil. Ideally by controlling the injection rate, carbon dioxide first displaces water from the flow channels and then slowly dissolves in the oil. Steam injection can then be applied to the formation without the previously experienced loss in steam injectivity.