Combined analysis of magnetic investigations and geological mapping of the Babouri-Figuil Basin (Northern Cameroon): Implications for hydrocarbon prospects

Abstract

The Babouri-Figuil Basin (BFB) is a frontier basin for petroleum exploration in northern Cameroon, where various studies indicated the presence of prospective source rocks but with limited information concerning its subsurface configuration. This work integrates the combination of magnetic survey and field geological data to assess the distribution of geological formations, and evaluate the basement configuration and thicknesses of sedimentary series in the BFB. Several filters (the reduced equator, the horizontal gradient, the analytical signal, and Euler deconvolution) were applied to the total magnetic field. Interpretation of magnetic data highlighted the presence of two main magnetic anomaly zones. The strong magnetic anomalies with an E-W elongated shape and the lobe-shaped low magnetic anomalies. Field geological survey reveals that the studied area is made up of claystone, siltstone, sandstone, and dolerite veins that were highly altered. In the BFB, the strong magnetic anomalies correlate well with volcanic intrusions mostly in the western part of the basin, while low magnetic anomalies correlate with sedimentary formations. The interpretation of the magnetic data reveals that lineaments primarily follow the NE-SW orientation, with the E-W and NW-SE orientations acting as secondary directions, aligning with the main regional structures. The different magnetic profiles exhibit a horst and graben configuration, characterized by a series of depressions (troughs) and uplifted areas that are made up of sedimentary formations, weathered basement, and unaltered basement. Sedimentary thickness ranges from 700 m to 2700 m. Generally, the eastern and western parts of the basin exhibit depressions characterized by thick sedimentation. These depressions also coincide with sites of petroleum source rock deposition previously identified and constitute the main prospective areas for petroleum exploration in the basin. The presence of igneous intrusions in the vicinity of organic-rich formations may imply the existence of an atypical petroleum system. It is recommended that petroleum exploration campaigns be intensified in the basin.