Significance of polymer on emulsion stability in surfactant‐polymer flooding

The influence of polymer on stability and shear rate on droplet size of emulsion is evaluated in the laboratory, microstructure of the emulsion is observed under a microscope, and the pore distribution of the cores is analyzed through mercury injection experiments. In the process of surfactant-polymer (SP) flooding, the thickness of polymer absorbed on the surface of the rock is calculated by a mathematical model. The experiments show that the polymer is good for the stability of emulsion, with the increase of shear rate, stability becomes better, and droplet size gets smaller. Due to the adsorption of polymer, the pore throat turns narrow, seepage velocity is increasing, and also the emulsion becomes more stable with the smaller-size droplets. During the single emulsifier flooding, the emulsion is easy to coalescence for its instability, and the seepage channel can be easily blocked, which leads to the high injection pressure. Consequently, the polymer plays an important role on emulsion stability in SP flooding. (c) 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42171.