Enhancing the Performance of Ubakala Clay for Use as Drilling Mud

ABSTRACT

This project is on the enhancement of the performance of an Ubakala clay sample for use as drilling mud. A sample of Nigerian clay (Ubakala clay) was used for the project. The clay sample was collected in a raw state, processed and experiments conducted on viscosity which is a very important property of drilling mud. Various concentrations of sodium carbonate were mixed with the clay sample and experiments were conducted to determine the viscosities of the control and the clay-sodium carbonate mixture at periodic time intervals and various speeds of agitation. Response Surface Methodology was used, and with the aid of a MATLAB programming, to study the data obtained from the experiment. The results showed that sodium carbonate concentration, speed of agitation and their various interactions terms and quadratic terms are the significant variables in the statistical model with time being the least significant of the three factors studied. Furthermore, on analysis of the kinetics of the process, a Gaussian model, having the highest values of R 2(50% for Gaussian model, and 25% each for Exponential and Exponential Power models) and the lines of best fit, effectively describes the kinetics of the process and the viscosity of the clay samples in relation to time, concentration of sodium carbonate and speed of agitation. Further work on the Gaussian model gave rise to a new model that can be used to determine the values of the kinetic constants. This new model showed that a Na2CO3 concentration of 2 4wt% and speed of agitation of 300 – 600rpm are the optimum operating parameters for enhancing the Ubakala clay sample for use as drilling mud.

Key words: Ubakala clay, viscosity, sodium carbonate, concentration, speed of agitation, time, statistical models, Gaussian, MATLAB, kinetics.