| 摘要 |
A water-soluble, charge, random copolymer of acrylamide and an alkali metal salt of an acrylamido-alkanoic acid such as alkali metal 3-acrylamido-3-methylbutanoate, having an average molecular weight of greater than about 50,000 or a critical temperature, Tc, of greater than 100.degree.C. in aqueous solutions containing up to 3 weight percent of CaCl2, has been found to maintain unusually stable and effective viscosities in the presence of salts such as NaCl and CaCl2 when added to water in minor amounts, thus making it a highly effective mobility control agent for secondary and tertiary oil recovery methods. Also within the scope of the invention are the acid form of the polymer, as well as terpolymers which additionally contain olefinically unsaturated monomers such as acrylic acid or sodium acrylate. |
