Chemometric Evaluation of Terpanes for Composition Allocation of Two Niger Delta Crude Oil Mixtures

Chemometric methods were employed to evaluate terpanes that correspond to the variations in the compositions of two Niger Delta crude oils (samples A-10 and F-00) in their mixes (samples B-82, C-64, D-46, and E- 28). Total abundances, plots, and hierarchical cluster analysis of C19 to C35 terpanes in the six oil samples suggest that the abundances and distributions of terpanes significantly correlated and did not mix correspondingly in the oil samples. Principal component analysis (PCA) showed that the first principal component (PC1) accounted for 95.77% of the total variance of individual terpanes among the oil samples with H30, OL, and NH30 explaining the most variance and NH25a, NH25b, and TR20d explaining the least variance, respectively. Plots of nine (9) ratios, derived from the most and least variant terpanes, gave R² values (0.4919 - 0.9749) that indicate the ratios moderately to very strongly correspond to the compositions of the two Niger Delta crude oils in the oil samples. Ratios of H30/H30+NH25b, OL/OL+NH25b and NH30/NH30+NH25b, with the highest R² values, showed very strong predictability (97.33%, 97.03% and 97.49%) for estimating the compositions of the two Niger Delta crude oils in their mixes.