RECOVERY OF OIL USING MICROEMULSIONS

摘要

Crude oil is a subterranean formation is recovered through the injection of at least one phase formed from a composition within the multiphase region of an oil-water-surfactant ternary diagram. One embodiment includes the injection of two or more mutually immiscible phases which would be in phase equilibrium within the multiphase region in the ternary diagram of a microemulsion system, at least one of the phases being a microemulsion. Low interfacial tensions exist between the immiscible phases in equilibrium. Where one of the phases in equilibrium comprises predominantly oil or predominantly water, in a further embodiment the microemulsion phase in equilibrium therewith can be injected alone to achieve efficient crude oil recovery. Where there are three phases in equilibrium, one of which comprises predominantly oil and another comprises predominantly water, in a further embodiment the remaining microemulsion phase in equilibrium therewith can be injected alone to achieve efficient crude oil recovery.