Interaction of Cationic Surfactants with Anionic Polymers for Improving Oil Production

Abstract

Summary This work provides insight into the interactions between the anionic polymers with different structures and the cationic surfactants with different self-assembly structures for the potential application in improving oil production from carbonate reservoirs. Cationic surfactants were selected to reduce the adsorption on carbonate rock surfaces. Anionic polymers include partially hydrolyzed polyacrylamides, sulfonated polyacrylamides and hydrophobic associating polymers. Cationic surfactants with different self-assembly behaviors were used. The mixtures of anionic polymers and cationic surfactants precipitated in deionized water due to the charge neutralization. By increasing the solution salinity, the compatibility became better and the solution turned to be transparent in high salinity water. Rheological measurements indicated that cationic surfactants significantly decreased the viscosity of hydrophobic associating polymers, and showed little effect on the viscosity of partially hydrolyzed polyacrylamide solutions. These results suggest that the polymer side chain affects the properties of surfactant-polymer mixtures. When mixing the hydrophobic associating polymers with cationic viscoelastic surfactants, significant viscosity increase was observed even at high temperature. This indicates that self-assembly structures of cationic surfactants play an important role in the performance of polymer-surfactant mixtures. Both polymer structures and surfactant behaviors should be taken into account in the design of optimal formulations.