Globally, Wyoming bentonite has been observed as the only accepted drilling fluid. Hence, the importance of investigating the mode by which Cissus populnea affects the rheological properties of local clay and as possible substitute for the international standard clay as drilling fluid. Ten samples of the local mud were taken at different locations of Afuze deposit, the stem bark of Cissus populnea was purchased in Ekiti State and authenticated at the herbarium, University of Ibadan, Nigeria. Its extraction was effected using the soxhlet extractor apparatus. Samples A and C, were respectively the mud of the local clay and a mixture of the Cissus populnea extract and the local clay. A control sample, B was formed from a mixture of water and the International Standard Wyoming bentonite which was obtained from the Petroleum Engineering Department of the University of Ibadan. Rheological properties of each of the samples were determined. The results of sample C (density (9.85 lb/gal), pH (9.9–11.3); funnel viscosity (50–62 seconds); hydroxylethyl cellulose at 600 rpm (22-38 cp); filtrate value (13.0–15.8 ml); sand content (0.50–0.81ppg); gel strength (15-21 lb/100ft2) and yield stress (7-13 lb/100ft2)) fell within the API RP–13B standard for drilling fluid. The analysis showed that the differences between samples A, B and C were negligible and that the local clay treated with Cissus populnea can serve as a substitute for foreign clay. KEYWORDS: bentonite, Cissus Populnea, local clay, mud weight, rheological properties
Effects of Cissus Populnea on the Rheological Properties of Local Clay
