According to the present invention, a composition and method for hydraulically fracturing a subterranean formation is provided. The composition comprises an aqueous mixture of a hydrated
polysaccharide, preferably a
galactomannan gum, the hydrated
polysaccharide having a plurality of bonding sites; a crosslinking agent for crosslinking the hydrated
polysaccharide at the bonding sites at the conditions of the subterranean formation with a polyvalent
metal ion to form a polyvalent
metal crosslink, thereby increasing the
viscosity of the hydrated polysaccharide; and a controlled
solubility compound for releasing a chelating agent for controllably breaking the polyvalent
metal crosslink and bonding with the polyvalent metal
ion released by breaking the crosslink, thereby decreasing the
viscosity of the hydrated polysaccharide. The method comprises the steps of injecting the above-described composition into the subterranean formation at fracturing pressures; allowing the controlled
solubility compound to begin breaking the polyvalent metal crosslink, thereby reducing the
viscosity of the hydrated polysaccharide and yielding a lower viscosity fluid; and removing the lower viscosity fluid from the subterranean formation.