Surfactant–Polymer Formulation for Chemical Flooding in Oil Reservoirs

A significant part of oil fields has reached a late stage of development, where technologies aimed at increasing the oil recovery factor are becoming particularly relevant. One such technology is surfactant–polymer flooding. To implement this technology, it is necessary to select a chemical formulation that retains its properties under reservoir conditions and enhances the efficiency of water flooding. This work presents a laboratory evaluation of various polymer and surfactant samples to develop an effective chemical formulation. The results demonstrate that anionic surfactants based on sodium laureth sulphate and betaine significantly reduce interfacial tension at the oil–water interface of the target reservoir. Furthermore, when combined with a partially hydrolysed polymer, the sodium laureth sulphate-based surfactant increases the capillary number by 4500 times (reducing interfacial tension from 32.77 mN/m to 0.065 mN/m and increasing the viscosity of the injected agent from 0.5 mPa·s to 4.36 mPa·s). Based on core flooding studies, it can be concluded that the proposed surfactant–polymer composition increases the oil displacement factor from the core sample by 0.15–0.24, depending on the injection volume. The selected formulation can be recommended for application in water flooding at the target reservoir.