Enhancement of thermal stability of drilling fluid using laponite nanoparticles under extreme temperature conditions

Aiming to overcome the problem of polymer degradation in water based drilling fluids under high temperature, this letter examined the influence of laponite nanoparticles on the thermal stability of drilling fluids. Firstly, a terpolymer (AAD) was synthesized through radical polymerization of acrylamide, 2-acrylamido-2-methylpropane sulfonic acid, and diallyldimethylammonium chloride monomers. The presence of laponite nanoparticles significantly improved the onset decomposition temperature and viscosities of AAD terpolymer at high temperatures, according to thermogravimetric analysis (TGA) and high temperature high pressure (HTHP) rheology results, respectively. Thereafter, water based drilling fluids containing AAD and laponite were formulated and aged under different temperatures. The drilling fluids containing laponite had a substantially higher viscosity than that without laponite ascribing to strong interactions between laponite and functional groups of the ADD terpolymer. This letter provided us a novel strategy to develop high temperature resistant drilling fluids for deep reservoir excavation. (C) 2019 Elsevier B.V. All rights reserved.