Controlling bentonite-based drilling mud properties using sepiolite nanoparticles

Sepiolite nanoparticles were added to the bentonite-based drilling mud to control its properties, and the effects of sepiolite nanoparticles on rheological properties and filtration loss of the bentonite-based drilling mud at different temperature and pressure conditions were studied by experiments. For the bentonite-based drilling muds with and without sepiolite nanoparticles, plastic viscosity, yield point, and fluid loss were measured at different temperature and pressure conditions, the core flooding experiments were also conducted at reservoir pressure and temperatures, and fluid loss and formation damage were measured. The results show that: sepiolite nanoparticles can be used to improve the plastic viscosity and yield point of saline and fresh bentonite-based drilling mud; the bentonite-based drilling mud with sepiolite nanoparticles shows a great stability of rheological properties over a wide range of temperature and pressure, especially at high temperatures and pressures; sepiolite nanoparticles reduce the fluid loss and the permeability reduction at reservoir pressure and temperatures. Sepiolite nanoparticles are an ideal additive for bentonite-based drilling mud.