Determination of the Distribution Patterns and Abundances of Trace Elements in Nigerian Crude Oil Using the AAS Technique

Abstract

Crude oil samples from four oil wells in Nigeria were analyzed for the following seven trace elements: V, Cr, Mn, Fe, Co, Ni and Pb using Atomic Absorption Spectrometric (AAS) analytical technique. The mean concentrations of these elements on a weight to weight basis were found to range from 0.017 ± 0.005 to 1.977 ± 0.397ppm. The results also show that V was the most abundant metal with Ovia 1 Long String (OLS) Oil well containing the highest concentration of V. The V/Ni ratio from the method used shows that Ovia 1 Long String (OLS) and Ovia 1 Short String (OSS) were the most and the least matured oil wells respectively. All the samples had comparably the same V/Ni ratio (1.16—1.77) implying identical source for all the oils. Furthermore, the calculated values of American Petroleum Institute (°API) gravity determined using the measurement of specific gravity (S.G.) of the crude oil samples range from 47.80 to 55.50. This suggests that the samples fall into one category of crude oil classification which in this case is light crude.