Bentonite-Inorganic Nanoparticle Suspensions for High-Temperature Drilling Applications

To address the challenges of insufficient high-temperature stability and poor filtration control in deep well drilling mud, this study introduces a synergistic nanocomposite approach by incorporating lithium magnesium silicate (LMS) and other inorganic nanoparticles as additives, rather than bentonite replacements. The effects of these nanoparticles on shear thinning, yield stress, and thixotropic behavior are analyzed using a Haake rheometer, a six-speed rotational viscometer, and a medium-pressure filtration apparatus, in conjunction with the rheological model. The results indicate that 2% BNT + 1% LMS composite suspension maintains a high yield stress (5.65 Pa) and low filtration loss (24.8 mL) even after aging at 120 °C, with an excellent Herschel–Bulkley model fit (R 2 = 0.9966, RMSE < 0.5 Pa), demonstrating outstanding thermal stability. Microscopic analysis reveals that LMS and BNT form a more compact “house-of-cards” structure through electrostatic interactions, reinforcing the spatial network strength of the suspension. This study provides theoretical support for the formulation of drilling mud in high-temperature and high-pressure environments.