In this research, a locally sourced clay from Niger-Delta Agbarha clay deposit formation was processed and treated to meet up with API standard specification for drilling fluid. Clay concentrations of 17.5 g, 21.0 g and 24.5 g of the local mud (Agbarha clay) and foreign Bentonite mud was prepared and analyzed using a standard measuring techniques. Laboratory analyses of the Properties of the Sample Mud (Agbarha clay) was compared with that of API Numerical Value Specification before and after

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... neficiation. The result shows that sample mud Weight, Apparent Viscosity (cp), Plastic Viscosity, Yield Point, Gel Strength (10 sec), Gel Strength (10min) showed values lower or a little short of API minimum numerical value standard while pH, Sand Content and-n‖ factor give a values that are higher than thatof standard API minimum numerical value after aging for 48 hrs without beneficiation. Therefore, there is a need to beneficiate this local mud sample (Agbarha clay) to meet that of API standard specification. After beneficiation with 5g Hydroxyl Ethyl Cellulose (HEC), the sample mud sand content remains the same; Mud weight, Apparent Viscosity, Plastic Viscosity, Yield Point, Gel Strength(10sec) Gel Strength (10min),-n‖ factor increased, pH of the mud sample reduced; all to values within API numerical value specification for standard drilling mud. Based on this research, Agbarha clay can therefore be recommended for formulation of drilling mud and can also serve as a substitute to foreign Bentonite mud. This will conserve foreign exchange, generate more employment and also enhance Nigerian local content development in the drilling component of oil and gas industry.