Patent ID: 6767867
Filing Date: 2004-07-27
Classification: A61K,A61Q,C02F,C04B,C08B,C08F,C08L,C09K,D21H,Y10S

Abstract:
A method of treating a subterranean zone penetrated by a well bore comprising introducing into the subterranean zone an aqueous well treating fluid comprising water and a water soluble polymer complex fluid loss control additive that comprises 1 part by weight of a cationic, anionic or amphoteric polymer comprising 40 mole % of 2-acrylamido-2-methyl propane sulfonic acid, 30 mole % of acrylamide, 20 mole % of acrylic acid and 10 mole % of vinyl pyrrolidone and 1 part by weight of a nonionic host polymer comprising hydroxyethylcellulose having 1.5 moles of ethylene oxide substitution and wherein said cationic, anionic or amphoteric polymer is formed in the presence of said nonionic host polymer.