Studying rheological behavior of nanoclay as oil well drilling fluid

Bentonite is commonly used to control the rheology and filtrate loss required for water-based drilling fluids. In this study, the effect of clay modification on fluid viscosity and its dispersion in oil-wet fluids were investigated and the thixotropic behavior of nanoclay and common bentonite samples were evaluated. Moreover, the viscosity of a nanoclay suspension which was produced from bentonite supplied by Kheirabad mine in Kerman (Iran) was studied, and the results were compared to common bentonite, used in oil well drilling fluids. The swelling index, cation exchange capacity, nanoclay dispersion in oil-wet phase, and the rheological properties of the produced mud were improved by purification and organification. This study showed that Kheirabad modified clay shows good behavior for drilling purposes at optimum clay concentrations. Moreover, organo clay was a proper additive with adequate rheological properties as an oil base drilling fluid.