Characterization of barite ores from selected locations in Nigeria for drilling fluid formulation

Barite is a non-metallic mineral composed of barium sulfate and is largely used by the oil and gas industry during drilling operations to control reservoir pressure. According to the American Petroleum Institute (API) standard, the specific gravity of barite should be a minimum of 4.1 to be applied as an additive in drilling fluid. In Nigeria, barite deposits are found in veins and cavity fillings hosted by varieties of rocks. Despite the abundance of barites reserves in Nigeria, the barites used in the Nigerian oil industry are imported from other countries. Therefore, in this research, barite deposits in some selected troughs in Nigeria were sampled and studied to determine their chemical composition and suitability as drilling fluid additives. The specific gravity of barites in the following states: Nasarawa, Benue, Plateau, Cross River, and Taraba was determined using the Pycnometer method, and their values were found to range from 2.9 to 4.3 on average. The quality of barite varies from location to location and with depth. The barite quality was enhanced when some low-grade barites were blended with a high grade, as shown in the blended samples of Plateau States, where specific gravity increased from 2.9 to 3.7. The results of XRF, E.D.X. and S.E.M. analysis of the samples show a predominance of BaO, Fe₂O₃, SrSO₄, and SiO₂. Samples from Benue (89.4% BaSO₄) and Taraba (96.5% BaSO₄) States met API standard for drilling mud application in terms of chemical composition, specific gravity, and a particle size distribution, while samples from Cross River (83.16% BaSO₄), Nasarawa (77% BaSO₄), and Plateau (10.88% BaSO₄) States need to be upgraded to meet the standard for usage as drilling fluid additives. However, they can be used as extenders or fillers in the rubber and paper industry.