Superhydrophobic Surface Fabrication for Strengthened Selective Water Shut-off Technology

A two-step solution immersion method was used to successfully fabricate a superhydrophobic film on the surface of the core, which can effectively separate oil and water. The optimal reagent concentration of the superhydrophobic surface was 1.0 wt % aminopropyl triethoxysilane + 0.7 wt % stearoyl chloride + 0.2 wt % triethylamine, suitable for reservoirs with a formation temperature around 40–100 °C, and the maximum contact angle of the prepared superhydrophobic surface was 155° with a sliding angle smaller than 3°. A scanning electron microscope and a contact angle measuring instrument were used to characterize the surface. Displacement experiments and oil–water separation experiments demonstrated that the superhydrophobic surface could significantly change the wettability of the formation and have a good selective water shut-off performance. The presented method is rapid and convenient and thus should be of significant value for the industrial fabrication of the superhydrophobic surface and should have a promising future in selective water shut-off in oilfields.