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 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. 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 rn 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 aided 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. polysaccharide investigated was a dry powder product
Introduction Polymers are finding increasing use to provide mobility control in tertiary oil recovery processes. Considerable work has been reported in recent years to determine a cost-effective polymer for use in flooding processes to control the fluid mobility of the aqueous front in the processes to control the fluid mobility of the aqueous front in the reservoir.
In effect the polymer is used to adjust the mobility of the injection water to the mobility range of the oil in the reservoir. Problems have been encountered in selecting appropriate water soluble polymers for this application. It has generally been concluded that several requirements are desirable for these polymers. Most prominent of these requirements, in addition to cost effectiveness which we will not address in this paper, are:Stable to mechanical shear during pumping and injection operations.
Demonstrable tertiary oil recovery in rock formations without plugging or severe degradation.
Stable to the presence of various salts and chemicals.
Thermally stable and biologically acceptable for various petroleum reservoirs.
Tests were performed with the Goodyear water soluble acrylic polymer, Wingflood, to compare it with several commercially available polyacrylamides and a polysaccharide. polyacrylamides and a polysaccharide. p. 523