Petroleum Geochemistry of Central Niger Delta

Akinsehinwa Akinlua¹ and Taiwo R. Ajayi^2
1Department of Chemistry, Obafemi Awolowo University, Ile-Ife, Nigeria
²Department of Geology, Obafemi Awolowo University, Ile-Ife, Nigeria

Oil samples obtained from the central Niger Delta were analyzed on GC and GC-MS for normal alkanes, straight chain isoprenoid hydrocarbons, aromatic hydrocarbons and biomarkers. The organic geochemical studies were carried out with the aim of assessing the origin and thermal maturity of the oils and depositional environment of the organic matter from which they derived, and to evaluate similarity or otherwise of oils from central Niger Delta with other parts of the delta. N-alkanes and straight chain isoprenoid hydrocarbons data showed that the oils were derived from organic matter of both terrestrial and depositional environment n marine origin. Pristane/Phytane ratios of the oils suggest that they were derived from organic matter deposited in more or less oxidizing environments. Biomarkers data also confirmed contributions from both marine and terrestrial organic matter. Both saturated and aromatic hydrocarbon biomarkers data indicated that the oils are thermally mature. The study showed that the central Niger Delta oils have similar organic geochemical characteristics with the oils from other parts of Niger Delta. The only striking difference is in the distribution of aromatic hydrocarbons, which may be a tool to differentiate oils from different parts of Niger Delta.

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