Methods, additives and compositions for temporarily sealing high temperature permeable formations
AssigneeHalliburton Company
InventorsHui-Min Hsu, John W. Burnham
Life of this patent
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Abstract
Methods, additives and compositions for selectively temporarily sealing high temperature permeable formations penetrated by well bores. The compositions are formed by dispersing a granular additive into an aqueous medium which contains a galactomannan gum treated with potassium pyroantimonate whereby the hydration rate of the gum is retarded at temperatures below about 120.degree. F. but increases at temperatures thereabove. When the composition is introduced into a high temperature permeable formation, it is heated whereby the treated galactomannan gum hydrates and the composition is formed into a stiff gel.
Claims25
An aqueous composition for temporarily sealing high temperature permeable formations comprising:
- an aqueous medium which contains a pH control agent present in an amount sufficient to maintain the pH of said composition above about 10;
- a galactomannan gum which has been treated with potassium pyroantimonate whereby the hydration rate of said gum is retarded at temperatures below about 120.degree. F. but the rate of hydration increases at temperatures thereabove, said treated gum being present in said composition in an amount whereby upon the hydration thereof said composition is formed into a stiff gel;
- and
- a water soluble gelling agent which hydrates rapidly in said aqueous medium present in said composition in an amount sufficient to increase the viscosity of said composition whereby said gum is suspended therein but said composition is still readily pumpable.
A granulated additive which when dispersed in an aqueous medium forms a viscous slurry suitable for introduction into a high temperature permeable formation and which when heated by the formation sets up into a stiff gel temporarily sealing the formation comprising:
- a particulate galactomannan gum which has been treated with potassium pyroantimonate whereby when said gum is dispersed in an aqueous medium having a pH above about 10 and a temperature below about 120.degree. F., the rate of hydration of said gum is retarded but when said aqueous medium containing said gum is heated to temperatures above about 120.degree. F. the rate of hydration of said gum increases;
- a water soluble gelling agent which hydrates rapidly in said aqueous medium to increase the viscosity thereof and maintain said particulate treated gum in suspension therein present in said additive in an amount whereby the weight ratio of gelling agent to treated galactomannan gum in said additive is in the range of from about 0.014 to about 0.14;
- and
- a pH control agent of a type and present in said additive in an amount effective to provide and maintain an aqueous medium pH of above about 10.
A method of temporarily sealing a high temperature permeable formation comprising the steps of:
- dispersing a granular additive into an aqueous medium having a pH maintained above about 10 and a temperature below about 120.degree. F., said additive comprising:
- a particulate galactomannan gum which has been treated with potassium pyroantimonate whereby when said gum is dispersed in an aqueous medium having a pH above about 10 and a temperature below about 120.degree. F., the rate of hydration of said gum is retarded, but when said aqueous medium containing said gum is heated to temperatures above about 120.degree. F. the rate of hydration of said gum increases;
- a water soluble gelling agent which hydrates rapidly in said aqueous medium to increase the viscosity thereof and maintain said particulate treated gum in suspension therein present in said additive in an amount whereby the weight ratio of gelling agent to treated galactomannan gum in said additive is in the range of from about 0.014 to about 0.14;
- and
- introducing the resultant aqueous suspension of treated gum into said high temperature permeable formation whereby said aqueous suspension is heated above about 120.degree. F. and said treated gum is hydrated to form a stiff gel which temporarily seals said formation.
Dependencies are inferred from the claim text.