“Improved Oil Recovery & EOR using Biological Enzymes”

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

(extract)

Patent Application number: 20080142230 Issued: June 19, 2008 Disclosed is an improvement to water-alternating-gas (WAG) processes for tertiary oil recovery that utilizes an enzyme composition to increase the ability of the water phase to recover and mobilize oil. In particular an enzyme trademarked as GREENZYME®, by Apollo Separation Technologies, Inc. of Houston, Tex. GREENZYME® is a biological enzyme that is a protein based, non-living catalyst for penetrating and releasing oil from solid surfaces and demonstrates the following attributes: GREENZYME® has the effect of increasing the mobility of the oil by reducing surface tension, decreasing contact angles and preventing crude oil that has become less viscous by heating or other means, from re-adhering to itself as it cools. GREENZYME® is active in water and acts catalytically in contacting and releasing oil from solid surfaces. GREENZYME® is effective up to 270 degrees Celsius in liquid phase under pressure and is not restricted by variations in the American Petroleum Institute (API) specific gravity ratings of the crude oil. GREENZYME® is not reactive with miscible or immiscible gases. GREENZYME® is not a live microbe and does not require nutrients or ingest oil. GREENZYME® does not trigger any other downhole mechanisms, except to release oil from the solid substrates. (ie: one function). In an overview, the water-alternating-gas (WAG) and enzyme system [4] is comprised of four (4) stages. The first stage includes a normal water composition injection stage [10] with at least one injection well, an alternative period of idle process known as the soak stage [20], followed by the gas injection stage [30] and then a recovery stage [40] of produced oil by one or more producing wells that are designed and configured to recovery oil from one or more injection wells. This water-alternating-gas (WAG) and enzyme system [5] is sequential and repeated based on the economics and availability of gas to inject, water availability, energy requirements to both produce oil and recover and re-inject the gas, and increased production and recovery rates achieved thru the combination of gas injection and enzyme addition. The water composition of the water composition injection stage [10] may include any substance known to those in the art. During the water composition injection stage [10], enzymes [115], such as GREENZYME® [110], are added to water and flow to an injection pump [150] where it is then pumped down an injection pipe [130], through the downhole well bore [135] and into the oil well formation [140]. The water composition acts to release the oil from solid surfaces, increase the mobility of the oil by reducing surface tension, decreasing contact angles, preventing crude oil that has become less viscous by heating or other means, from re-adhering to itself as it cools and acts catalytically in contacting and releasing oil from solid surfaces. Blockages in the oil well formation [140] may be reduced or eliminated as well. The enzymes [115] are pushed into the oil well formation [140] to further contact oil particles [142] thereby increasing contact volume. The soak stage [20] as it is known, allows the water and enzyme [115] composition to permeate the oil well formation [140] and the enzymes [115] to reach maximum oil releasing efficiency. The enzymes [115] remains active in the water or hot water compositions and acts catalytically in contacting and releasing oil from solid surfaces. It is not restricted by variations in the American Petroleum Institute (API) specific gravity ratings of the crude oil. The soak stage [20] lasts between 0-30 days depending on the type and size of the oil well formation [140]. The soak stage [20] may be omitted when the gas injection stage [30] immediately follows the water composition injection stage [40]. Normally following the soak stage [20] is a gas injection stage [30] to which a gas injection pump [160] is connected to the oil well formation [140] via an injection pipe [130] and a wellbore [135]. Miscible, near miscible or immicsible gas flows into the gas injection pump [160] where it is under pressure and flows into the oil well formation [140] via an injection pipe [130] and a wellbore [135]. The gas then displaces the water composition and enzymes [115] pushing oil particles [142] toward the part of the oil well formation [140] where recovery operations occur. Following the gas injection stage [30] is the recovery stage [40] in which one or more extraction pump [165] is connected to the oil well formation [140] via a retrieval pipe [170] and an uphole well bore [175]. In the recovery stage [40], the extraction pump [165] is activated causing the oil particles [142] to be transferred from the oil well formation [140] through the uphole well bore [175] and retrieval pipe [170] to be transferred for refining. This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to make and use the invention. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.