Experimental investigation on laponite as ultra-high-temperature viscosifier of water-based drilling fluids

Aimed at the problem of poor anti-temperature capability of polymer viscosifier, which cannot meet the needs of ultra-high-temperature water-based drilling fluid, laponite has been studied as an ultra-high-temperature viscosifier. The property of thickening, temperature resistance and salt tolerance of laponite are evaluated. In addition, the viscosifying mechanism of laponite under high temperature has also been analyzed. Experimental results show that laponite has excellent viscosifying ability and thermal stability, and it is able to function at temperature of up to 260 °C. Moreover, the viscosifying effect at high temperature is superior to high-temperature viscosifiers used worldwide. In practice, the reduced rate of apparent viscosity value of bentonite dispersion formulated with 1 wt% laponite is 0% after aging at 260 °C for 16 h, while that of bentonite dispersion with 1 wt% HE300 is 94.7%. Research results indicate that laponite is compatible well with other commonly used additives and has promising application as ultra-high-temperature viscosifier in formulating ultra-high-temperature water-based drilling fluid.