Influence of carbon ash on the rheological properties of bentonite dispersions

Bentonite was widely used in water-base drilling fluids. The influence of carbon ash on the rheological properties of bentonite dispersions was investigated in this paper. Different measurements (particle size distribution, X-ray diffraction, rheology, density and fluid loss) were used to study the mechanism of carbon ash in adjusting the rheological properties of bentonite dispersions. The rheological properties were determined as a function of the carbon ash concentrations according to the Herschel–Bulkley model. The experimental results indicated that the carbon ash adsorbed on the external surface of bentonite particles improved the dispersion of bentonite in the water-base drilling fluids. The investigated carbon ash salt-resistance and stability demonstrated that carbon ash had the excellent capacity to adjust the rheological properties of bentonite dispersions.