Earth metal peroxide fluidized compositions
Disclosed is an alkaline earth metal peroxide concentrate, or fluidized suspension, for addition to aqueous hydraulic fracturing fluids to efficiently decrease the viscosity of the hydrated, hydrophilic polysaccharide polymer in the system. The concentrate comprises a hydrophobic, water insoluble liquid, an organophilic clay suspension agent, a polar activator, a sparingly-soluble alkaline earth metal peroxide, and an anionic surfactant. Advantageously, these concentrations, or suspensions, exhibit high flash points, making them easier to transport using commercial transportation means.
1. A method for reducing the viscosity of an aqueous gelled polymer-containing fracturing fluid during a hydraulic fracturing operation of a subterranean formation, the method comprising:
continuously adding a viscosity breaker composition to the fracturing fluid during the hydraulic fracturing operation, wherein the breaker composition comprises:
a hydrophobic liquid selected from one or more chemically manufactured Group IV and Group V category base oils, as classified by the American Petroleum Institute, and combinations thereof,
an organophilic clay suspension agent,
a polar activator,
a sparingly-soluble alkaline earth metal peroxide, and
a surfactant.
2. The method of claim 1 , wherein the polar activator is propylene carbonate.
3. The method of claim 1 , wherein the earth metal peroxide is calcium peroxide, magnesium peroxide, or a mixture thereof.
4. The method of claim 1 , wherein the hydrophobic liquid is present in an amount which is:
a) at least from about 20 vol. % to about 90 vol. % of the total composition volume, and
b) is sufficient to obtain a flash point greater than 200° F. for the peroxide/synthetic fluid composition when tested in accordance with ASTM D-93.
5. The method of claim 1 , wherein the surfactant is an ionic surfactant.