Anionic surfactant based on oil-solid interfacial interaction control for efficient residual oil development

A large amount of oil film remains on the rock surface after conventional oil displacement methods. Developing novel surfactant to achieve efficient oil film peeling, and unveiling the oil-solid interaction mechanism behind is of great significance. Herein, a novel anionic surfactant 1,2-decanediol dihydroxypropyl sulfonates (D-diHS), which was composed of one hydrophobic tail and two branched hydrophilic heads containing hydroxyl groups and sulfonate groups was synthesized via a feasible two-step reaction. The experimental results showed that DdiHS could alter the wettability of rock surface from oleophilic to strong hydrophilic, with the water contact angle reducing substantially from 100.8 to 17.8 . Compared with traditional surfactants, D-diHS exhibited superior oil film peeling performance with excellent salinity tolerance (oil film reduction rate > 74.3 % at 6 wt% salinity). Based on the nano-mechanical experimental results, the reduced adhesion caused by improved hydrophilicity and the produced electrostatic repulsion between the oil film and rock surface played crucial roles in the oil film peeling. The novel anionic surfactant D-diHS proposed in this work was designed from the perspective of oil-solid interfacial interaction control, exhibiting great application potential in efficient residual oil development.