Abstract: In order to study the reasons for the great differences in viscosity, salt resistance and oil displacement efficiency between polymer surfactant and polymer, FT-IR spectrogram and scanning electron microscope (SEM) were used to characterize the molecular structure and aggregation morphology of polymer surfactant and polymer. The injectivity, conductivity, fluid diversion and oil displacement efficiency of polymer surfactant and polymer were analyzed by core physical simulation experiment and nuclear magnetic resonance technology. The results show that the viscosity of the polymer surfactant with the same mass concentration (500 to 2,000 mg/L) was 3 to 4 times that of the polymer due to the presence of a reticular aggregate structure; the improvement by the polymer surfactant to the reservoir seepage profile was up to 79.3%, while the improvement by the polymer was only 63.9%; in the medium-high permeable reservoirs, the final recovery present of the polymer displacement was 6.36 Percentages higher than that of the polymer displacement. This study plays an important theoretical guiding role in the application of polymer surfactant as a new displacement agent for greatly improving recovery efficiency in medium-high permeable reservoirs with high water cut and high recovery percent.

Key words: polymer surfactant, compatibility, physical simulation, nuclear magnetic resonance, improve the recovery efficiency, fluid diverting, conductivity