Patent ID: 7385019
Filing Date: 2008-06-10
Classification: C09K

Abstract:
1. A polymer fluid, the polymer comprising: non-ionic hydrosoluble functional groups corresponding to one or more of the following monomers: acrylamide, N substituted acrylamide derivatives and N-vinylamides; ionic functional groups corresponding to one or more of the following monomers: acrylic acid, methacrylic acid, maleic anhydride, acrylamidomethylpropylsulphonate, styrene sulphonic acid, vinyl sulphonic acid, vinylpyridine, quaternary ammonium salts of vinylpyridine, N-vinylimidazole, quaternary ammonium salts of N-vinylimidazole, and monomers of general formulae:  where R A=O or NH, R R R hydrophobic functional groups corresponding to one or more of the following monomers: monomers of general formula —(CH where R the viscosity of the fluid increasing when the fluid is subjected to shear, wherein the ionic monomers comprise at least one of vinylpyridine with a pH of less than 2 or quaternary ammonium salts thereof, and N-vinylimidazole having a pH of less than 7 or quaternary ammonium salts thereof and wherein the proportion of ionic monomer units in the polymer is more than 0.1 mol %.