Synthesis of a novel borate ester Anion-Nonionic surfactant and its application in viscosity reduction and emulsification of heavy crude oil

In this study, emulsification viscosity reduction research was carried out on Xinjiang heavy oil. A new boron-containing anionic-nonionic surfactant (SYW) was synthesized by the esterification-sulfonation reaction using 1,3 propylene glycol polyether (PPG), boric acid, maleic anhydride (MA), and sodium metabisulfite as raw materials. The resulting SYW was analyzed and characterized by elemental analysis, GPC, FT-IR, 1H NMR, and XPS. Based on the experimental results, SYW showed a viscosity reduction rate of 97.3 %. The surfactant SYG was obtained by compounding SYW with oleic acid and ethanolamine at a 3:1:1 ratio, which further improved the viscosity reduction rate to 98.6 %. Both SYW and SYG significantly reduce the interfacial tension. Under the experimental conditions, SYG can reduce the interfacial tension value from 25.6mN/m to 0.07mN/m, and increase the negative charge Zeta potential on the surface of oil droplets. The dispersive phase of the emulsion containing SYG changed from water droplets to oil droplets with a particle size of 3.68 μm and a more uniform distribution. The mechanism of viscosity reduction of SYW was revealed. SYW in water phase and asphaltene molecules in oil phase formed water Bridges through hydrogen bonding with water to realize the emulsification process.