Performance and mechanisms of enhanced oil recovery via amphiphilic polymer flooding in high salinity reservoir

The amphiphilic polymer has excellent performance and is expected to replace traditional polymer oil-displacing agent in China. In this study, the iso-viscosity method evaluates the oil displacement performance of the betaine-type amphiphilic polymers with different content of hydrophobic groups in high salinity reservoirs. Rheometer, emulsion stability analyzer, laser particle size analyzer, and visualization of microscopic displacement are used to explore their oil displacement mechanism. The results show that the content of hydrophobic groups, and the recovery ratio of polymer flooding shows a positive correlation. The difference in the displacement performance reflects the difference in the viscoelasticity of the displacement system and the ability to emulsify crude oil. The synergistic effect of the two aspects further improves the oil washing efficiency. This study provides a reference for the practical application of the amphiphilic polymer, providing a theoretical basis to select polymer flooding agents in high salinity reservoirs.