Numerical Simulation of Heat Flow and Hydrocarbon Generation in the Anambra Basin: Towards a Calibrated Petroleum Systems Model

The Anambra Basin's hydrocarbon prospectivity assessment is hampered by insufficient understanding of its thermal history and the spatial variability of source rock maturity, partly because no calibrated three-dimensional petroleum systems model has previously been constructed for this basin to integrate available geochemical, structural, and stratigraphic datasets. This study constructs a calibrated three-dimensional petroleum systems model for the Anambra Basin, simulating heat flow history, source rock maturity evolution, and hydrocarbon generation, migration, and accumulation. A three-dimensional geological model was built using available seismic reflection profiles and well data, representing the Awgu, Nkporo, and Imo shale formations as potential source rock intervals. Basal heat flow history was calibrated by matching simulated vitrinite reflectance profiles to measured values at twelve wells and outcrop sections. Kinetic parameters for oil and gas generation from Type II and Type IIS kerogen were applied to the mature source intervals. Hydrocarbon migration was simulated using the flow simulation algorithm in Petromod 2D and 3D software. The study presents original maps of source rock maturity windows, timing of peak oil and gas generation, and predicted charge volumes at identified trap locations. A sensitivity analysis quantifies the impact of heat flow uncertainty on predicted charge risk. The calibrated model is submitted to the Department of Petroleum Resources as a prospectivity tool for the Anambra Basin licensing round. Keywords: petroleum systems modelling, Anambra Basin, heat flow, source rock maturity, hydrocarbon migration.