A New Polymer for Enhanced Oil Recovery

Abstract A new water soluble acrylic polymer has been developed for use as a mobility control agent in enhanced oil recovery. This polymer was designed to meet the fundamental requirements for a mobility control application, including cost effectiveness, stability to mechanical shear, non-plugging in porous media, demonstrable tertiary oil recovery, stability in the presence of salts and chemicals, and retention of viscosity after extended exposure to elevated temperatures. This polymer has been extensively tested in the laboratory and compared to existing mobility control polymers, such as partially hydrolyzed polyacrylamides and polysaccharides. One of the major attributes that this polymer demonstrated was a retention of viscosity after extended aging at elevated temperatures in various media, including high brine conditions. Laboratory core floods have shown this polymer to be equally effective in tertiary oil recovery in both polymer-augmented waterfloods and caustic-polymer waterfloods when compared to commercial partially hydrolyzed polyacrylamides. This new polymer is available in a liquid form (latex) and does not contain any hydrocarbon vehicle, such as those present in inverse- emulsion polyacrylamides. The question of cost-effectiveness will not be addressed in this paper since it involves so many parameters that are beyond the scope of this technical evaluation. Not all of the polymers evaluated were compared in each of the various test programs, but every effort was made to compare polymer types generically, i.e., polyacrylamides and a polysaccharide to rule out any glaring differences which might be inherent in their physical form, liquid or dry, molecular weight, or method of preparation. The only polysaccharide investigated was a dry powder product.