Patent ID: 9033047
Filing Date: 2015-05-19
Classification: C09K,E21B,Y02P

Abstract:
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.