Elemental Constituents of Crude Oil, Formation Water, and Source Rocks in Muglad Basin - Sudan

Abstract

This study had been done on the elemental constituents of the oilfield water, crude oil, and the source rocks in Muglad basin using the atomic absorption spectroscopy (AAS) technique in order to find out the source of trace elements found in crude oil and to evaluate the quality of Sudanese crude oil on the basis of the concentration of trace elements, which have adverse effects on the specifications of the crude oil. Twenty four representative samples of different types were collected from different sites and tested for detemnnation of concentration of the elements: Ca, Mg, Na. Cu, Co, Ni, Zn, Pb, Cd, and Fe. The evaluation of the data obtained, for the concentration of these elements, had been done by applying non-parametric test to find out the p-values in order to prove whether these results are statistically significant or not. All the p-values obtained were found to be less than 0.05, which indicate that all tests, carried out through this work, are statistically significant. By comparison of elemental constituents of Sudanese crude oil, regionally with Libya crude oil and intemationally with Venezuela, Califomia, and Canada crude oils, it was found that the Sudanese crude oil contains the lowest concentration of some harmful trace elements like nickel (Ni) and lead (Pb) which can verify its quality. Also it was found that the concentrations of the elements under study show very high values in case of source rocks, which indicate that the source rocks can be considered as the main possible source of trace elements, found in crude oil. The element cadmium (Cd) was not detected in all samples of the source rocks, which had been analyzed for determination of trace elements, because of its low concentration in the earth crust (0.2- 0.5ppm).