Petroleum systems development of the Bornu Basin, onshore NE Nigeria

Abstract

The formation of the West and Central African Rift Systems (WCARS) reflects intra-plate deformation linked to the Early to Late Cretaceous opening of the South Atlantic Ocean. From an economic point of view, the USGS (2010) estimated WCARS and Chad Basin in particular to contain, up to 2.32 BBO and 14.62 TCF. However, there has been no exploration success in the Nigerian Sector, Bornu Basin, principally because of a poor understanding of the basin tectono-stratigraphy and petroleum systems. In this study, we use 2D and 3D seismic reflection, geochemical and field data to investigate the tectono-stratigraphy and model the development of the petroleum systems. 3D, 2D and 1D models of the pre-Bima Sandstone lacustrine shales, the Gongila Formation and the Lower Fika marine shales show lack of hydrocarbon generation and expulsion from the source rocks with poor total organic content (TOC). Inferred models show possible hydrocarbon generation and expulsion from the high TOC prospective source rocks. The hydrocarbon generation time range from Albian to late Maastrichtian and the expulsion from late Albian to Paleocene. Igneous intrusion is observed, in our study, to result in increased maturity and thermal degradation of the host source rocks. It also enhances localized hydrocarbon generation and expulsions potential of the source rocks.