The massive exploration and production well drillings in Nigerian oilfield indicate the demand for drilling fluid supplements such as baryte, in managing over-pressured formations and preventing hazardous blowouts. The underdevelopment of Nigerian solid minerals has created a wide gap between the demand and supply of the local resource, whereas there exist some assertions that the Nigerian baryte quality is below the American Petroleum Institute, API, standard. This study aimed at testing and evaluating qualitatively, based on API standards, some baryte ores from the Benue area, Nigeria, to establish their usefulness or otherwise in oilfield drilling operations. General field studies and sampling with laboratory studies were done including flame tests, X-ray Diffraction and X-ray fluorescence, to confirm mineralogy and chemical compositions of the barytes respectively and very importantly, the API tests prescribed for drilling grade barytes were carried out. The results showed impressive quality barytes with a specific gravity range from 4.10 to 4.49 and concentration of alkaline earth metals as calcium, Ca, 20mg/kg to 48mg/kg, particle sizes processed within API standard requirement, and the weight percentage of BaSO4 composition of the ores ranged from 93.55% to 99.61%. There were no significant impurities of threat such as carbonates, iron ores, silicates and sulphides. The estimation of reserves and proper development of the resource is highly recommended as the quantity and quality might enhance the sustainability of local drilling grade baryte supply and save Nigeria the current huge capital flight and other plights

There is a very high demand for the American Petroleum Institute (API) grade baryte in Nigeria due to the continuous massive drilling in oil and gas fields. Considering the presumption that local baryte is of low quality, processed baryte is imported, leading to great national revenue losses. Some baryte deposits in the Northern Cross River, Nigeria were sampled and studied in field and laboratories, based on API standard requirements (2004 and 2010), to ascertain their suitability for use as weighting additive in drilling fluids. Furthermore, flame testing of the samples yielded yellowish-green flame indicating barium presence; X-ray diffraction (XRD) and X-Ray fluorescence (XRF) analyses confirmed the mineralogy and chemical composition of the samples, respectively. The results revealed the Specific Gravity, SG range of 4.37 to 4.52; concentration of alkali earth metals as calcium 8.40mg/kg to 62.10mg/Kg; the residue >75micron and particle sizes <6microns processed had normal range, respectively below 3% and 30%; and the samples’ BaSO4 %weightcomposition was over 90%. The chemical analysis indicated no significant undesired minerals. Galena gangue with baryte was observed in three locations though these could be easily beneficiated through physical separation. The tests and analyses result qualified the Northern Cross River baryte samples as high-grade API standard baryte, suitable for oilfield drilling fluid. Further estimation of the baryte reserves in this region was highly recommended, as this might proffer a substantial solution to the sustainable supply of excellent local quality drilling baryte in Nigerian oilfields.