초록 ▼

The present invention relates to a method of fracturing subterranean formations and placing proppant material in the created fracture utilizing carbon dioxide or nitrogen containing fluid. An aqueous liquid-liquid carbon dioxide emulsion fluid is prepared having an internal phase ratio in the range

The present invention relates to a method of fracturing subterranean formations and placing proppant material in the created fracture utilizing carbon dioxide or nitrogen containing fluid. An aqueous liquid-liquid carbon dioxide emulsion fluid is prepared having an internal phase ratio in the range of from about 50 to in excess of about 96 percent and introduced into the subterranean formation to be fractured. The emulsion is heated by the formation to a temperature above the critical temperature of carbon dioxide and the carbon dioxide is caused to be converted to a vapor whereupon the emulsion becomes a foam. The volume of liquid carbon dioxide is adjusted as the volume of proppant material varies to at least substantially maintain a constant internal phase ratio in the treatment fluid. When nitrogen is utilized, a foam is produced on the surface by admixing gaseous nitrogen with the gelled fluid. The formation is fractured by the treatment fluid and the proppant is placed in the created fracture. The fluid having maintained therein substantially a constant internal phase ratio is capable of transporting greater quantities of proppant than foams having a comparable quality.

대표청구항 ▼

A method of fracturing a subterranean formation penetrated by a well bore comprising: admixing an aqueous liquid containing varying quantities of a proppant material and a gelling agent with liquid carbon dioxide and a surfactant which is present in an amount sufficient to form an emulsion, said emu

A method of fracturing a subterranean formation penetrated by a well bore comprising: admixing an aqueous liquid containing varying quantities of a proppant material and a gelling agent with liquid carbon dioxide and a surfactant which is present in an amount sufficient to form an emulsion, said emulsion having an internal phase ratio of from about 50 to in excess of about 96 percent; adjusting the volume of carbon dioxide admixed with said aqueous liquid to at least substantially maintain said internal phase ratio constant as the quantity of said proppant is varied whereby the viscosity of said emulsion is caused to remain substantially unchanged as the quantity of said proppant varies; introducing said 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 and cause a fracture to be formed in said subterranean formation; maintaining said 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 foam from said emulsion, said foam having a viscosity immediately after formation which is substantially the same as the viscosity of the emulsion; and depositing at least a portion of said proppant material in said subterranean formation with said foam.