Exploring geothermal and hydrocarbon potential with aeromagnetic data in Guri and environs in Chad Basin

Abstract

This study analyses aeromagnetic data over Guri and environs to evaluate geothermal and petroleum prospects. The Total Magnetic Intensity (TMI) anomalies, ranging from – 1324.43 nT to +997.75 nT, reveal significant subsurface heterogeneity, with strong positive anomalies linked to igneous intrusions and crystalline basement highs, and negative anomalies marking sedimentary basins and low-susceptibility rocks. Upward continuation to 4 km effectively suppresses shallow sources, enhancing deeper tectonic lineaments and basement structures critical for hydrocarbon and mineral exploration, while gridded continuation provides localized insights into anomaly orientations consistent with Nigeria’s basement complex geology. Spectral analysis identifies dual-depth magnetic sources, with shallow crustal features (~7–9 km) and deeper basement anomalies (20–45 km), underscoring a multi-layered crustal architecture. Curie point depth and geothermal gradient analysis highlight Blocks 1 and 2 as favourable for oil generation and geothermal exploitation, whereas deeper centroids in Blocks 3 and 4 suggest gas-prone systems with reduced geothermal viability. Overall, the integration of TMI mapping, upward continuation, and spectral analysis demonstrates the effectiveness of aeromagnetic methods in delineating intrusive bodies, tectonic lineaments, and geothermal potential across Nigeria’s inland basins. Based on these findings, hydrocarbon exploration should prioritize Blocks 3 and 4 for gas-prone systems and Blocks 1 and 2 for oil-prone zones. Geothermal energy development is best concentrated in Blocks 1 and 2, which exhibit favourable heat flow and gradients, while largescale geothermal investment in Blocks 3 and 4 should be avoided due to limited viability. These results provide a robust framework for guiding exploration strategies, supporting both hydrocarbon prospectivity and geothermal energy development in the region.