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A method of fracturing a subterranean formation with a stabilized foamed fracturing fluid comprising from about 30 percent to in excess of about 95 percent by volume of carbon dioxide with the remainder comprising a substantially anhydrous liquid and a selected surfactant. The foam is formed in situ

A method of fracturing a subterranean formation with a stabilized foamed fracturing fluid comprising from about 30 percent to in excess of about 95 percent by volume of carbon dioxide with the remainder comprising a substantially anhydrous liquid and a selected surfactant. The foam is formed in situ by injection of a stabilized liquid-liquid emulsion containing liquid carbon dioxide into a well bore penetrating the formation. The temperature and pressure of the emulsion is controlled to maintain the carbon dioxide in the liquid phase during injection into the well bore. Thereafter, the carbon dioxide is heated by the subterranean formation to a temperature above about 88°F. at which time the stabilized emulsion spontaneously forms a high quality stabilized foam.

대표청구항 ▼

A method of fracturing a subterranean formation penetrated by a well bore comprising: admixing a substantially anhydrous liquid containing ethylene glycol and from about 0 to about 10 percent by weight aqueous fluid with a proppant material, liquid carbon dioxide and a selected surfactant to form a

A method of fracturing a subterranean formation penetrated by a well bore comprising: admixing a substantially anhydrous liquid containing ethylene glycol and from about 0 to about 10 percent by weight aqueous fluid with a proppant material, liquid carbon dioxide and a selected surfactant to form a stabilized emulsion, said emulsion comprising from about 30 to in excess of about 95 percent by volume carbon dioxide and said surfactant being present in said emulsion in an amount sufficient to stabilize said emulsion; introducing said stabilized emulsion into said well bore penetrating said subterranean formation at a temperature below the critical temperature of carbon dioxide and under sufficient pressure to maintain the carbon dioxide as a liquid; maintaining said stabilized emulsion within said formation for a sufficient time to permit said emulsion to be heated to a temperature above the critical temperature of carbon dioxide to form a stabilized foam from said emulsion, said foam having a viscosity immediately after formation which is substantially the same as the viscosity of the emulsion; contacting said formation with said foam at a pressure sufficient to create at least one fracture in said subterranean formation; and depositing said proppant material in said fracture in said subterranean formation.