Fracturing using gel with ester delayed breaking
AssigneeBJ Services Company
InventorsJeffrey C. Dawson, Hoang Van Le
Life of this patent
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Abstract
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.
Claims11
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;
- and
- contacting 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.
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;
- and
- a citric acid ester to form a gelling fluid;
- and
- contacting 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.
Dependencies are inferred from the claim text.