Patent ID: 7012044

Claim:
A method of fracturing a subterranean formation, comprising: forming a base fluid by blending together water and a carboxylated guar polymer, maintaining said base fluid substantially free from cation producing additives that interfere with the anionic groups of said carboxylated guar polymer; adding a crosslinking agent to the base fluid to form a gel; and injecting the gel into at least a portion of the subterranean formation at high pressure to form fractures within the formation; wherein a test gel of the carboxylated guar polymer maintains a viscosity of at least 360 cps at 105 s −1 , after viscosity testing maintained for seven hours at a shear rate of 105 s −1 and a temperature of 150° F.; and wherein said test gel is prepared by adding 0.9 gram of said carboxylated guar polymer to 500 ml of water containing 0.5ml of a 50 weight percent aqueous TMAC solution; rapidly agitating the water, carboxylated guar polymer and TMAC for 30 minutes; adjusting the pH to 5.1 with glacial acetic acid; and then adding 0.50 ml of a zirconium lactate based crosslinking agent, which has a zirconium concentration measured and reported as the oxide of 8.5 weight percent ZrO 2 , with good agitation until gelation occurs.