Evaluation of Local Clays from Edo and Delta State as Feedstock in Drilling Fluid Formulation

Abstract

This work investigates the suitability of clay samples collected from Ogwashi-Ukwu and Oyede in Delta State as well as Ikpeshi and Afuze in Edo State for drilling mud formulation. The American Petroleum Institute (API) Standard for drilling mud formulation was adopted using 350 ml of water and 21.0 g of fresh unweathered clay samples collected at 5 ft depth from the mentioned location. The Clay Samples were processed (Weighed, dried, and sieved) and the drilling mud formulated with other additives (Carboxyl Methyl Cellulose, NaOH and Barite). The results from the four samples showed that the pH of Ikpeshi was alkaline while the other samples were acidic. When the mud was mixed with NaOH at 0.5 g, 1.0 g, 1.5 g, 2.0 g, 2.5 g and 3.0 g, the pH rose to 13 and 14 for the Ikpeshi and Ogwashi-Ukwu, while the pH values of the mud formulated with the standard clay gave 9 and increased to 13 when 3.0g of NaOH was added.  The mud densities for the four mud samples formulated were within 8.40 to 8.60ppg before addition of chemical additives. After beneficiation addition with Barite, the densities of the four formulated mud rose and almost equal to that of the standard mud of 8.95 ppg at 3 g additive. The plastic viscosity of  the locally formulated mud were within 1 to 2 cp before adding cmc and increased to 30cp for Ikpeshi mud, 27 cp for Ogwashi-Ukwu, 17 cp for Afuze and 18 cp for Oyede. The filtration rate for Afuze and Ikpeshi mud was 33 ml and 36 ml for 30 mins and may need additional filtration agent to be up to standard. The results have shown that the Nigeria Clay can be used with beneficiation. Therefore, the production of mud materials locally, should be encourage to reduce the cost of drilling by avoiding importation.