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AssigneeBaker Hughes Incorporated
InventorJames Crews
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Fluids viscosified with viscoelastic surfactants (VESs) may have their viscosities affected (increased or reduced) by the indirect or direct action of a composition that contains at least one fatty acid that has been affected, modified or reacted with an alkali metal halide salt, an alkaline earth metal halide salt, and/or an ammonium salt and a water soluble base. The composition containing the resulting saponification product is believed to either act as a co-surfactant with the VES itself to increase viscosity and/or possibly by disaggregating or otherwise affecting the micellar structure of the VES-gelled fluid. In a non-limiting instance, a brine fluid gelled with an amine oxide surfactant has its viscosity broken with a composition containing naturally-occurring fatty acids in canola oil reacted with a water soluble base such as NaOH, KOH, NH4OH, and the like with an alkali halide salt such as CaCl2, MgCl2, NaCl, NH4Cl and the like.
A method for affecting the viscosity of an aqueous fluid gelled with a viscoelastic surfactant (VES) comprising providing to an aqueous fluid gelled with at least one VES a composition in an amount effective to increase or decrease the viscosity of the gelled aqueous fluid, where the composition comprises a soap reaction product of a fatty acid with an alkaline compound selected from the group consisting of alkali metal halide salts, alkaline earth metal halide salts, ammonium salts and combinations thereof, in the presence of a water soluble base selected from the group consisting of alkali metal bases, ammonia, ammonium hydroxide, methylamine, trimethylamine, ethylmethylamine, ethanolamine, triethanolamine, urea, choline, and mixtures thereof.
A method for affecting the viscosity of an aqueous fluid gelled with a viscoelastic surfactant (VES) comprising providing to an aqueous fluid gelled with at least one VES a composition comprising from about 50 to about 20,000 ppm of a soap reaction product of a fatty acid with an alkaline compound in the presence of a water soluble base, where the alkaline compound is selected from the group consisting of alkali metal halide salts, alkaline earth metal halide salts, ammonium salts and combinations thereof, where the fatty acid is selected from the group consisting of those found in plant oils and animal oils, where the alkali or alkaline earth metal halide salt has a cation selected from the group of consisting of Na+, K+, Li+, Cs+, Ca+, Mg+, Ba+, Sr+, NH4+, and mixtures thereof, and the ammonium salt is selected from the group consisting of ammonium bromide, ammonium iodide, ammonium bicarbonate and ammonium nitrate, and where the water soluble base is selected from the group consisting of alkali metal bases, ammonia, ammonium hydroxide, methylamine, trimethylamine, ethylmethylamine, ethanolamine, triethanolamine, urea, choline, and mixtures thereof.
An aqueous fluid comprising:
An aqueous fluid comprising:
Dependencies are inferred from the claim text.