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.