Formulation of Water Based Drilling Fluid Using Local Mud Uwheru & Otor-Udu Clay

Drilling fluid is one of the major substances used when drilling a well, as it serves numerous purposes such as lubrication and cooling of the drilling bit, cuttings removal to mention a few. And one of its major constituent is the bentonite, clay that serves as the dispersed phase. The cost of procuring the bentonite clay for the production of drilling fluid is expensive because of its importation into the country hereby increasing the overall cost of drilling a well. This paper investigated the suitability of suspected clay from Uwheru and Otor-Udu village in Delta State, Nigeria for the production of water based drilling fluid. The mud was formulated using 21.0g of each clay local sample and 350ml of fresh water. Different concentrations of pH and viscosity chemical additives were used. Comparative analysis was made on the drilling mud sample formulated from clay obtained from the study areas namely (Uwheru and Otor-Udu) to determine their suitability for the formulation of drilling fluids and to determine if it meets the API standard. The properties tested for include the mud density, pH, sand content and rheological properties. After laboratory work was conducted, the two formulated mud samples had same mud weight of 8.5ppg which was slightly below the API standard for bentonite clay of 8.65minimum and 9.60maximum. A pH control additive (NaOH) and Viscosifier additive (CMC) were added. In conclusion, analysis was made on the experimental values of Uwheru which had values of 3cp for 2cp for the 600rpm and 300rpm rheological readings respectively, pH of 5, sand content of 0.1ml and density of 8.5ppg while that of Otor-Udu had values of 3cp and 2cp for the 600rpm and 300rpm rheological readings respectively, pH of 5, sand content of 0.05ml and density of 8.5ppg. From the analysis made between the local clay formulated drilling fluid samples and the standard API values for bentonite using graphs and charts, the local clay can be improvised for bentonite.