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US 7,399,732 B2Granted
Fracturing fluid containing amphoteric glycinate surfactant
AssigneesCalfrac Well Services Ltd., Chemergy Ltd.
InventorsTravis L. Allan, Junad Amin, Alan K. Olson, Ronald G. Pierce
Life of this patent
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Abstract
An improved method and fracturing fluid for hydraulic fracturing of a subterranean formation, the fracturing fluid including a surfactant, a water soluble or dispersible anionic organic salt, an acid and a low molecular weight organic solvent.
Claims25
A fluid for fracturing a subterranean formation comprising:
- (i) a surfactant having the general formula
- where R1-R2 are each an aliphatic group of C1-C4, branched or straight chained, saturated or unsaturated, R3 is a group of C12-22, branched, straight or cyclic, saturated or unsaturated;
- (ii) a water soluble or dispersible anionic organic or inorganic salt;
- (iii) an acid;
- and
- (iv) a low molecular weight organic solvent;
- wherein the ratio of said salt to said surfactant is in the range of 1:4 to 1:2;
- wherein said acid is selected from the group consisting of formic acid, citric acid, hydrochloric acid and acetic acid;
- and
- wherein the viscosity of the fluid can be lowered by raising the pH thereof.
7 more elements
A visco-elastic fluid for fracturing a subterranean formation, the viscosity of the fluid being breakable subsequent to fracturing, said visco-elastic fluid comprising:
- (i) a surfactant having the general formula
- where R1-R2 are each an aliphatic group of C1-C4, branched or straight chained, saturated or unsaturated, R3 is a group of C12-22, branched, straight or cyclic, saturated or unsaturated;
- (ii) a water soluble or dispersible anionic organic or inorganic salt;
- (iii) an acid;
- and
- (iv) a viscosity reducing agent comprising a low molecular weight organic solvent comprising an alcohol;
- wherein said acid is selected from the group consisting of formic acid, citric acid, hydrochloric acid and acetic acid.
4 more elements
A method of fracturing a subterranean formation comprising the steps of:
- providing a visco-elastic surfactant based hydraulic fracturing fluid comprising:
- (i) a surfactant having the general formula
- where R1-R2 are each an aliphatic group of C1-C4, branched or straight chained, saturated or unsaturated, R3 is a group of C12-22, branched, straight or cyclic, saturated or unsaturated;
- (ii) a water soluble or dispersible anionic organic or inorganic salt;
- (iii) an acid;
- and
- (iv) a low molecular weight organic solvent,
- pumping said fracturing fluid through a well bore and into a subterranean formation at a sufficient pressure to cause fracturing of said formation;
- and
- lowering the viscosity of said fluid subsequent to said fracturing to facilitate formation clean-up, wherein said acid is selected from the group consisting of formic acid, citric acid, hydrochloric acid and acetic acid.
7 more elements
Dependencies are inferred from the claim text.