| abstract |
ABSTRACT The invention comprises a thickening agent comprising an aqueous-soluble polymeri-zation product of one or more water-soluble mono-mers which are sufficiently water-soluble to form at least a 10 weight percent solution when dis-solved in water and which undergo addition polym-erization to form polymers which are water-solu-ble; and at least one second monomer of the for-mula: III 32,120-F wherein R is a hydrocarbyl radical which contrib-utes hydrophobic character to the second monomer, Z is a divalent linking group, M is a divalent hydrocarbyl or substituted hydrocarbyl radical and Y is an ionic species which contributes hydro-philic character to the molecule. These compositions are useful for thick-ening aqueous mediums, in particular, for thicken-ing aqueous media containing water-soluble elector-lytes. Such thickened aqueous media retain their viscosity when subjected to shear, heat or high electrolyte concentrations. The thickened aqueous solutions may be used in enhanced oil recovery pro-cesses as fluid mobility control agents, fracturing fluids and drilling muds, as well as hydraulic fluids and lubricants. 32,120-F |