Evaluating the thermal effect on the rheological properties of waste vegetable oil biodiesel modified bentonite drilling muds using Vipulanandan model

Abstract

In this investigation, the effects of the temperature on the flow characteristics of waste vegetable oil biodiesel modified bentonite drilling mud were quantified. The biodiesel contents in the drilling muds are varied from 0 to 9% of the volume of the water in order to reduce the yield point and upper shear stress limit produced by the mud during drilling activities under simulated thermal condition ranging from 28°C to 180°C. The results revealed that the bentonite drilling mud loaded with 6 vol.% waste vegetable oil biodiesel demonstrates fairly favorable rheological properties compared to others when exposed to similar heat treatment. Moreover, the rheological behavior of biodiesel-free bentonite mud and samples loaded with biodiesel were quantified using the Vipulanandan model and compared with others existing models used in the industry such as: Bingham plastic model and Herschel-Bulkley model. It was observed that the Vipulanandan model predicts satisfactorily the shear thinning relationship between the shear stress and shear strain rate of the modified bentonite drilling muds. Furthermore, by using the Vipulanandan model, the maximum shear stress values for 0%, 3%, 6% and 9% biodiesel content at 28°C are found to be 63.67 Pa, 84.54 Pa, 84.64 Pa and 85.02 Pa, respectively. When exposed to heat treatment at 180°C, the maximum shear stress values recorded for 0%, 3%, 6% and 9% are 53.18 Pa, 67.39 Pa, 64.52 Pa and 72.70 Pa, respectively, which represent a reduction of 14% to 16% in the upper shear stress limit.