초록 ▼

A well treatment fluid composition comprises a solvent (such as water), a polymer soluble or hydratable in the solvent, a crosslinking agent, an inorganic breaking agent, and an ester compound. Preferably, the hydratable polymer is a polysaccharide, such as galactomannan, cellulose, or derivatives t

A well treatment fluid composition comprises a solvent (such as water), a polymer soluble or hydratable in the solvent, a crosslinking agent, an inorganic breaking agent, and an ester compound. Preferably, the hydratable polymer is a polysaccharide, such as galactomannan, cellulose, or derivatives thereof. The crosslinking agent is preferably a borate, titanate, or zirconium-containing compound. The inorganic breaking agent is preferably a metal-based oxidizing agent, such as an alkaline earth metal or transition metal-based oxidizing agent. The ester compound is preferably an ester of polycarboxylic acid, such as an ester of oxalate, citrate, or ethylenediamine tetraacetate. One example of a suitable ester compound is acetyl triethyl citrate.

대표청구항 ▼

1. A method of fracturing a subterranean formation, the method comprising:obtaining a well treatment fluid comprising a solvent, a polymer which is either soluble or hydratable in the solvent, a crosslinking agent, a breaking agent, and an ester; andcontacting the well treatment fluid and least a po

1. A method of fracturing a subterranean formation, the method comprising:obtaining a well treatment fluid comprising a solvent, a polymer which is either soluble or hydratable in the solvent, a crosslinking agent, a breaking agent, and an ester; andcontacting the well treatment fluid and least a portion of the subterranean formation at pressures sufficient to form fractures in the formation; wherein the ester is acetyl methyl citrate, acetyl ethyl citrate, acetyl propyl citrate, acetyl butyl citrate, or acetyl triethyl citrate. 2. The method of claim 1, wherein the solvent is water. 3. The method of claim 1, wherein the polymer is a galactomannan gum, a glucomannan gum, a guar, a derived guar, cellulose, a cellulose derivative, guar gum, a guar gum derivative, locust bean gum, Karaya gum, carboxymethyl cellulose, carboxymethyl hydroxyethyl cellulose, or hydroxyethyl cellulose. 4. The method of claim 1, wherein the polymer is polyvinyl alcohol, polyacrylamide, or poly-2-amino-2-methyl propane sulfonic acid. 5. The method of claim 1, wherein the crosslinking agent is a boron compound, a titanium compound, a zirconium compound, or mixtures thereof. 6. The method of claim 1, wherein the breaking agent is a percarbonate, a perborate, a peroxide, or a perphosphate. 7. The method of claim 1, wherein the breaking agent is an alkaline earth metal percarbonate, an alkaline earth metal perborate, an alkaline earth metal peroxide, an alkaline earth metal perphosphate, a zinc peroxide, a zinc perphosphate, a zinc perborate, or a zinc percarbonate. 8. The method of claim 1, wherein the breaking agent is calcium peroxide, magnesium peroxide, or zinc peroxide. 9. The method of claim 1, wherein the ester is acetyl methyl citrate, acetyl ethyl citrate, acetyl propyl citrate, or acetyl butyl citrate. 10. The method of claim 1, wherein the ester is acetyl triethyl citrate. 11. A method of fracturing a subterranean formation, the method comprising:contacting water or brine with guar gum, hydroxypropyl guar, carboxymethyl guar, carboxymethyl hydroxypropyl guar, or carboxymethyl hydroxyethyl cellulose to form a base gel,contacting the base gel with:a borate, titanate or zirconium crosslinking agent;an alkaline earth peroxide or zinc peroxide; anda citric acid ester to form a gelling fluid; andcontacting the gelling fluid and at least a portion of the subterranean formation at pressures sufficient to form fractures in the formation; wherein the citric acid ester is acetyl methyl citrate, acetyl ethyl citrate, acetyl propyl citrate, acetyl butyl citrate, or acetyl triethyl citrate.