Both-branch amphiphilic polymer oil displacing system: Molecular weight, surfactant interactions and enhanced oil recovery performance

Hydrophobically modified polyacrylamidepolymers were synthesized by an aqueous micellar copolymerization, the N -benzyl- N - n -hexadecyl acrylamide being used as hydrophobic comonomer. The effect of the molecular weight (MW) and surfactant interactions on the rheological properties and oil-water interfacial activity were studied. The results indicate that increasing MW, the critical aggregation concentration of amphiphilic polymer will be decreased, and the network structural strength increased, which was measured by fluorescent probes, DLS and electron microscope. Mixing with the surfactant, sodium dodecyl sulfate (SDS), the solution viscosity increased at first and decreased later on with increasing the ratio of SDS concentration, and the dynamic interfacial tension between oil and water can be reduced by two orders of magnitude compared to the polymer solution only. The result of enhance oil recovery performance of the polymer/surfactant compound system is that it can significantly reduce the residual oil saturation due to the synergistic effect of the increasing viscosity and surface activity. The overall recovery efficiency was raised by 10–25% OOIP compared to the baseline polymers.