Analysis of Petroleum System for Exploration and Risk Reduction in the South-Eastern Inland Basins of Nigeria

Although several acreages exist within the inland basins of southeastern Nigeria, the distribution of key petroleum system elements and associated generation, migration and accumulation processes have not been fully understood. This has hindered extensive exploration and subsequent development plans within these important hydrocarbon provinces. In this paper, outcrop, well logs and seismic data have been integrated with sequence stratigraphic and geochemical modelling techniques to allow for better understanding of the petroleum system elements and processes within the inland basins. Results from petroleum system analysis reveal the existence of two key petroleum systems namely, the Albian-Santonian system of the Abakaliki Basin and the Campano-Maastrichtian system of the Anambra Basin. Integrated analytical studies using sequence stratigraphic and geochemical modelling techniques unravelled the presence and distribution of source, reservoir, seal packages and associated generation, migration and accumulation processes. Structurally, the presence of hanging walls, footwalls, horst blocks and collapsed crest trapping systems provided both possible hydrocarbon migration pathways for generated hydrocarbons and good entrapment for hydrocarbon accumulation. Common Risk Seg-ment (CRS) maps indicate zones of low, moderate and high risks intervals, which are prospective and favourable for hydrocarbon exploration. This study thus, provides a guide to oil and gas exploration and potential in the inland basins of Nigeria.