Nanofluids have become a popular research topic in oil and gas exploration and development due to their potential to enhance oil recovery. the shrinkage behavior of solid-interface oil film was investigated when contacting with 50 mg/L modified lamellar nanofluid in a self-made visualization model. Additionally，oil sand washing experiments were also conducted to determine the oil washing efficiency of the modified lamellar nanofluid at a concentration of 50 mg/L under different conditions. The results showed that the solid-interface oil film shrunk slowly and no wedge-shaped region was observed under simulated formation water condition. However，under the modified lamellar nanofluid environment，the solid-interface oil film shrunk significantly with an obvious wedge-shaped region and two contact lines including an outer contact line and an inner contact line. The shrinkage rate of the outer contact line was 8.5817×10^-5 cm/s while the shrinkage rate of the inner contact line was 0.6617×10^-5 cm/s. The results from oil sand washing experiments exhibited that the oil-washing efficiency of the modified lamellar nanofluid increased with the increase of oil sand particle size and temperature. What’s more，the oil-washing efficiency also increased rapidly at first，followed by a slow increase as the oil sand immersion time was extended，with an optimal immersion time of（8±2）hours. The oil-washing efficiency of the modified lamellar nanofluid could reach as high as 95.7%. These achievements break through the limitation that only high-concentration spherical nanoparticles can form structure disjoining pressure，providing a possibility for the applications of lamellar nanofluid in oilfield and a technical reference for pilot construction processes.