Enhanced oil recovery with hydrophobically associating polymers containing sulfonate functionality
 This invention relates to a method for enhanced recovery of petroleum from a subterranean oil-bearing formation. More particularly, this invention relates to secondary or tertiary recovery of oil employing a polymer thickened aqueous drive fluid. The polymeric viscosifier for the drive fluid is selected from a class of hydrophobically associating water soluble polymers containing one or more water soluble monomers and a water insoluble monomer or group. The water soluble groups are acrylamide and a salt of an ethylenically unsaturated sulfonic acid and the water insoluble group is a higher alkyl acrylamide. These polymers, when dissolved in an aqueous brine solution, have the ability to substantially increase the viscosity of the solution. The control of displacement fluid mobility results in more uniform sweep efficiency and improved oil recovery. In addition, aqueous solutions of these hydrophobically associating polymers exhibit enhanced viscosification, reduced salt sensitivity and other desirable rheological properties found useful in chemically enhanced oil recovery processes. 
Exxon Research and Engineering Company
C Y
C09K Y10S
inventional additional
Salvatore J. Paul L. Jan
Pace Valint Bock