Enhanced oil recovery in low permeability reservoirs
First Claim
1. A method for enhancing hydrocarbon recovery in reservoirs with a permeability of less than about 10 millidarcy, the method comprising:
- (a) providing a subterranean reservoir with a depth of at least about 10,000 feet, bottom-hole injection pressure of at least about 15,000 psig, and a permeability of less than about 10 millidarcy comprising one or more hydrocarbons and water therewithin;
(b) providing a wellbore in fluid communication with the subterranean reservoir;
(c) dehydrating a carbon dioxide composition comprising at least 95% carbon dioxide and more than 150 parts per million of water to form a dehydrated carbon dioxide composition comprising less than 150 parts per million of water;
(d) injecting about 1% to about 2% hydrocarbon pore volumes of the dehydrated carbon dioxide composition into the subterranean reservoir through the wellbore under conditions such that any water in or near the wellbore is reduced or eliminated; and
(e) after injecting the dehydrated carbon dioxide composition into the subterranean reservoir, injecting a substantially anhydrous composition with less than 150 parts per million of water into the subterranean reservoir through the wellbore, the substantially anhydrous composition comprising carbon dioxide and one or more surfactants and being suitable to form a foam upon contact with water within the subterranean reservoir.
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Abstract
A method for enhancing hydrocarbon recovery in low permeability reservoirs comprises first providing a subterranean reservoir comprising one or more hydrocarbons and water therewithin and a wellbore in fluid communication with the subterranean reservoir. Next, a substantially anhydrous composition is injected into the reservoir through the wellbore. The substantially anhydrous composition comprises carbon dioxide and one or more surfactants. The composition is suitable to form a foam upon contact with the water within the reservoir. The method often results in reduced wellbore corrosion and hydrate formation, reduced reservoir fingering, and enhanced carbon dioxide sweep efficiency over conventional methods.
27 Citations
15 Claims
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1. A method for enhancing hydrocarbon recovery in reservoirs with a permeability of less than about 10 millidarcy, the method comprising:
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(a) providing a subterranean reservoir with a depth of at least about 10,000 feet, bottom-hole injection pressure of at least about 15,000 psig, and a permeability of less than about 10 millidarcy comprising one or more hydrocarbons and water therewithin; (b) providing a wellbore in fluid communication with the subterranean reservoir; (c) dehydrating a carbon dioxide composition comprising at least 95% carbon dioxide and more than 150 parts per million of water to form a dehydrated carbon dioxide composition comprising less than 150 parts per million of water; (d) injecting about 1% to about 2% hydrocarbon pore volumes of the dehydrated carbon dioxide composition into the subterranean reservoir through the wellbore under conditions such that any water in or near the wellbore is reduced or eliminated; and (e) after injecting the dehydrated carbon dioxide composition into the subterranean reservoir, injecting a substantially anhydrous composition with less than 150 parts per million of water into the subterranean reservoir through the wellbore, the substantially anhydrous composition comprising carbon dioxide and one or more surfactants and being suitable to form a foam upon contact with water within the subterranean reservoir. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method for enhancing hydrocarbon recovery in reservoirs with a permeability of less than about 10 millidarcy, the method comprising:
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(a) providing a subterranean reservoir with a depth of at least about 10,000 feet, bottom-hole injection pressure of at least about 15,000 psig, and a permeability of less than about 10 millidarcy comprising one or more hydrocarbons and water therewithin; (b) providing a wellbore in fluid communication with the subterranean reservoir; (c) providing dehydrated carbon dioxide with less than 150 parts per million of water; (d) injecting about 1% to about 2% hydrocarbon pore volumes of the dehydrated carbon dioxide into the subterranean reservoir through the wellbore; and (e) adding one or more surfactants to the dehydrated carbon dioxide after about 1% to about 2% hydrocarbon pore volumes of dehydrated carbon dioxide has been injected in step (d), wherein the dehydrated carbon dioxide reduces or eliminates water in or near the wellbore. - View Dependent Claims (14, 15)
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Specification