Enzyme enhanced oil recovery (EEOR) for water alternating gas (WAG) systems

Abstract

The present disclosure relates to the release or recovery of subterranean hydrocarbon deposits and, more specifically, to a system and method for enhanced oil recovery (EOR), by utilizing enzyme compositions and water-alternating-gas (WAG) methods for injecting water compositions, followed by miscible, near miscible or immiscible gas into subterranean formations for oil recovery operations.

Description

FIELD OF INVENTION [0001]The present disclosure relates to the release or recovery of subterranean hydrocarbon deposits and, more specifically, to a system for enhanced oil recovery (EOR), by utilizing enzyme compositions and water-alternating-gas (WAG) methods for injecting ambient, cold or heated fluids containing enzymes, followed alternatingly, with gas injection into subterranean formations.BACKGROUND OF INVENTION [0002]It is a common practice to treat production wells and other subterranean formations with various methodologies in order to increase petroleum, gas, oil or other hydrocarbon production using enhanced (secondary or tertiary) oil recovery. Enhanced oil recovery processes include Water-Alternating-Gas (WAG), cyclic steam, steamflood, in-situ combustion, the addition of micellar-polymer flooding, and microbial solutions.DEFINITIONS [0003]One common practice regarding enhanced oil recovery is to treat viscous crude in subterranean formations using cyclic steam to incr...

AI Technical Summary

Benefits of technology

[0055]Another embodiment includes the use of an enzyme composition for treatment between liquid and gas injection cycles or treatment of the well during or after the water injection cycle such that the enzyme can be injected as a heated liquid into the well if needed. The use of an enzyme heated to 80 to 90 degrees Celsius before injection into a well to minimize pour point flow restrictions and to maximize injection pressure efficiency of the injected water or gas is another aspect of the disclosure. It is noted that the enzyme is active in a diluted range of 0.01 to 100 percent and is suitable, but not limited to, a working range of 3 to 10 percent for injection with water. Injection of enzyme may have different points of addition and can occur along with large injections of water that are part of a designed WAG treatment or in concentrated or diluted enzyme fluids that are injected “on the fly” to water injection lines that actively pump water. Metered addition of enzyme to maximize efficient use of enzyme and optimize WAG performance is also possible.

[0056]Another embodiment includes the use of an enzyme composition in combination with water in a WAG treatment to extend the effective consumption of miscible or immiscible gas being injected thus improving overall capacity while offsetting or minimizing reduced recoverability normally associated with reduced use of gas injection. Some oil wells have formations that are suitable for straight gas injection where no WAG treatment is used. This also means a high rate of gas injection that may or may not be sustainable as demand for straight gas and WAG injection grows.

[0057]Another embodiment includes the use of an enzyme composition to be injected into a subsurface formation to improve the mobility of heavier crude oils going from the injection well to one or more producing wells and to prevent plugging in producing wellbores or restricted flow areas as well as plugging the pipelines.

[0058]Another embodiment is the use of an enzyme composition for penetrating asphaltenes and waxes at the injection wellbore prior to or during WAG injection as well as minimizing similar build up that can occur at one or more producing wellbores during production.

Problems solved by technology

Secondly, displacing the low-viscosity crude oil away from the injection well toward an oil production well in fluid communication with the oil-bearing formation and continuously recovering the low-viscosity crude oil from the oil production well.

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