Method for temporarily sealing a permeable formation

Claim 1

The method as defined in claim 1 wherein the slurry includes in addition a degradation agent for a hydrated cross-linked galactomannan gum said degradation agent characterized as having a characteristic time delay effectiveness in degradating said gum.

Claim 2

A method for temporarily plugging a permeable formation located adjacent to a well bore located in a subterranean formation which comprises injecting into said formation prior to any substantial hydration of the treated galactomannan gum a slurry composition which comprises: a. from about 300 to about 750 pounds of a galactomannan gum which is pretreated with an effective amount of a material which releases borate ions when dispersed in an aqueous solution to render the gum less hydrophilic than normal when dispersed in an aqueous solution having about a neutral to alkaline pH value and normal hydrophilic characteristics in aqueous solution having an acidic pH value; b. a water-soluble organic polymeric suspending agent of at least one of a water-soluble homopolymer or copolymer of acrylamide or methacrylamide from about 6 to about 30 pounds; c. a buffering agent in an amount ranging from about 24 to about 60 pounds wherein said buffering agent is at least one of NaH2PO4-Na2HPO4, boric acid-borax, sodium carbonate-sodium bicarbonate, sodium bicarbonate, citric acid-sodium hydroxide, or boric acid-sodium hydroxide; d. at least one of an acidic material which releases an ion in aqueous solution which cross-links a hydrated galactomannan gum upon hydrolysis decreases the pH of an aqueous solution said acid material further characterized as having a characteristic time delayed hydrolysis rate, in an amount sufficient to overcome the effect of said buffering agent after a period of time; e. a sufficient quantity of an aqueous solution to make about 1, 000 gallons of said slurry composition.