Enhance Filtration and Inhibition Properties of Bentonite Water-Based Drilling Fluid Using Nano-silica

This study evaluated the effects of nano-silica and bentonite concentrations on drilling fluid rheology and filtration loss performance and studied the effect of nano-silica on shale’s swelling performance and dispersion performance to evaluate the enhancement effect of nano-silica on drilling fluid performance. The experimental results show that nano-silica has a negligible impact on rheology, which leads to a slight increase in plastic viscosity and a slight decrease in yield value. 0.8% nano-silica is the best addition to reduce the filtration loss of drilling fluid; nano-silica can also reduce shale swelling and inhibit shale hydration and dispersion, and after aging at 100 °C, nano-silica leads to the cementation of shale particles. Adding nano-silica to water-based drilling fluids is important for solving the drilling problems in shale formations.