Assessment Of Barite Deposit In Nassarawa State For Oil Drilling Application

ABSTRACT

Drilling fluids play sophisticated roles in the drilling process which include, keeping formation fluids at bay, stabilizing the wellbore without damaging the formation, lubricating the bit and drill-string and clearing cuttings from the bit face. Weighting agents are compounds that are dissolved or suspended in drilling fluid to increase its density. The effect of density also contributes to the stability of the borehole by increasing the pressure exerted by the wellbore fluid onto the surface of the formation down hole. There has been a very long desire in order to increase the density of wellbore fluids, and through various researches, a variety of methods exist. Barium Sulphate (BaSO4) also known as barite is the prevalent weighting material but there is need to develop local barite for use in drilling fluid. This research was aimed at the investigation of some characteristics of Nigeria barite and its effect on mud density. Six barite samples were collected from different locations in the area of Wuse in Nasarawa state, Nigeria. The barite showed distinct specific gravities ranging between 4.38 SG and of 4.11 SG and compared with the American Petroleum Institute (API) standard. The characterization of these samples was carried out using the SEM/EDS which showed some traces of rare earth metals present. Six water-based mud samples were also prepared and the barite was added in different proportions of 40g, 80g and 120g to form the mud weight and this ranged from 9 lb/gal and 10.7 lb/gal which showed the effect of the specific gravity on the mud densities. Sample 1 which contains 40g of barite showed the highest yield point of 4.00 lb/100ft2 and sample 2 which contains 80g of barite showed the lowest yield point of 0.975 lb/100ft2 while there were 10 secs gel strengths 1.00 lb/100ft2 and 1.5lb/100ft2 respectively. With the specific gravity of the barite samples obtained, which meet the API standard, the weighting material in these locations would be fit for use majorly in the oil and gas industry as additives to drilling mud.