Improvement of Local (Umuna) Clay for the Production of Drilling Mud

Abstract

The continuous importation of foreign bentonite in the presence of proved and potential clay deposits spread across states in the country is not consistent with the government desire and commitment for the development of local content. This research explores the possibility of improving the Umuna local clay samples for the production of drilling mud. The clay samples were experimentally analysed in accordance with API standard of measurement. The obtained results show a marked trend as most of the considered rheological parameters such as yp, PV, gel strength, yp/PV, viscosity @600rpm and fluid loss were far away from satisfying the minimum required API standard specification for drilling mud. While parameters such as mud density, n-factor, K-factor, specific gravity and filter cake all satisfy the minimum required API standard specification for drilling mud production. The rheological properties of the local clays were significantly improved after beneficiation with 2g PAC-R. These obtained result after beneficiation now equated to that of the imported bentonite and also satisfy the required minimum API standard specification. The local clay fell under the inactive soil type based on its average activity value of 0.52. The presence of oxide compositions and cation exchange capacity (CEC) range of 70 – 150 Meq/100g suggests and confirms that the analyzed clay is of the montmorillonite family, with traces of illite which is good for drilling mud production. The obtained average thinner cake value (0.35) for the local clay is more desirable in drilling operations for reducing the risk of pipe sticking. This property with the combination of high value (29.39av) of consistency factor (k) and low value (0.28av) of the power law flow behavior index (n) portrays the clay sample been very much adequate for effective hole cleaning due to its high viscosity resulting from high consistency factor (k) and enough shear thinning property derived from the low power law flow behavior index (n).