High temperature and oil tolerance of surfactant foam/polymer–surfactant foam

Abstract

Foam performance during oil displacement is closely related to the reservoir environment. In this study, both bulk and porous media experiments were conducted to investigate surfactant foam and polymer–surfactant foam behaviors at high temperature and with crude oil. After aging at 90 °C for 90 days, the foam drainage half-life of the aged polymer–surfactant foam was four times longer than that of the fresh surfactant foam. Scanning electron microscope images indicated that, even experienced high temperature aging, the polymer and surfactant could still develop multilayer complexes to enhance the foam film strength. Within a certain oil content, the foam stability in the presence of oil could be better than in the absence of oil. Stereoscopic microscope images revealed that the existing form and content of oil in the foam film had played a vital role. Core flooding experiments further confirmed that stable surfactant foam and polymer–surfactant foam could generate in the presence of waterflooded residual oil and give rise to additional oil recovery of 15.35% and 35.75% at 90 °C, respectively. The positive responses of this study may be attractive to potential foam field applications.