Systematic investigation of the physicochemical properties of eco-friendly biobased anionic-nonionic surfactants for enhanced oil recovery

In the present study, a series of biobased anionic-nonionic surfactants were used to evaluate their physicochemical properties for predicting the effectiveness in chemical enhanced oil recovery (EOR) applications. And the amphoterics surfactants are lignin polyether sulfonates with different polymerization degrees. The results indicated that the hydrophobic carbon chain length and oxyethyl groups in surfactant molecular structure effected on the surface tension, salt tolerance, adsorption amount on the quartz sand and interfacial tension of the lignin polyether sulfonates. The salt tolerance experiments demonstrated that the lignin polyether sulfonates exhibited good tolerance to salt addition, even in the salinity solutions containing divalent metal ions. The adsorption amount of lignin polyether sulfonates on the quartz sand was higher by increasing the ratio of liquid to solid or increasing surfactant concentration until the saturated adsorption was achieved. Interfacial tension (IFT) studies indicated the effects of the concentration of NaOH and inorganic salts on the IFT between lignin polyether sulfonates and Daqing crude oil, and ultra-low IFT would be obtained.