A water-based mud (WBM) has been prepared with a mixture of beneficiated clay and 3.5g of XCD. The rheology of the spud mud produced was compared with an equivalent mud made with bentonite at various shear rates and times. The beneficiated clay reproduced the values obtained with bentonite for plastic viscosity, yield point and other rheological data to less than 1% standard deviation. This beneficiated clay has a good prospect of replacing bentonite locally as a clay additive in drilling fluid (spud mud) when mixed with the polymer XCD.
