Surfactant and surfactant-polymer flooding are important chemical enhanced oil recovery (cEOR) methods used to mobilize crude oil remaining in reservoir rocks after primary and secondary production. A significant proportion of the original oil in place remains trapped due to capillary forces, unfavorable mobility ratios, reservoir heterogeneity and incomplete sweep efficiency. Surfactants improve microscopic displacement efficiency by reducing oil-water interfacial tension, while polymers enhance macroscopic sweep efficiency through mobility control by increasing the viscosity of the injected aqueous phase. The performance of surfactant-polymer systems depends on reservoir conditions, including salinity, temperature, crude oil composition and rock properties, as well as on interactions among surfactants, cosolvents and polymers.
The aim of this work was to support the development of surfactant compositions for petroleum industry applications through improved laboratory screening methods and the investigation of formulation-related interactions. Particular attention was paid to high-salinity formation waters, where surfactant performance is often limited by reduced solubility and stability. The research focused on three areas: improving laboratory testing methods, evaluating surfactant compositions in synthetic formation waters of different salinities, and investigating the effects of cosolvents and viscosity-modifying polymers.