Magnetically inferred regional heat flow and geological structures in parts of Chad Basin, Nigeria and their implications for geothermal and hydrocarbon prospects

This study analysed high-resolution aeromagnetic data over part of Chad Basin, Nigeria to determine the implications of geological structures and heat flow on the geothermal and hydrocarbon potential of the basin. Curie Point Depth (CPD) analysis, Curvature analysis and Source Parameter Imaging (SPI) were applied in this study. The estimated CPD and heat flow range from 11to19km and from 75to125mW/m2 respectively. The geological structures in the area predominantly trend in the E-W direction, followed by the ENE-WSW direction. Other prominent structural trends include NE-SW and WNW-ESE. The depths to the magnetic sources range from about 0.1 km to over 5 km. A large number of shallow-seated magnetic structures, believed to be intra-sedimentary intrusive bodies, were mapped in the southern and northwestern parts of the study area. The estimated heat flow in Chungul Buturi and Gumsa areas was found to be sufficient for the economic exploitation of geothermal energy. The results of this study showed that the basin is thermally matured for hydrocarbon generation. However, high magnitudes of heat flow and the presence of a large number of intrusive bodies in parts of the basin might have been the reason behind the unsuccessful attempts to find hydrocarbon in commercial quantities in the basin. The results also showed that the basin has a higher potential for gas accumulation than oil. Future exploration for commercial hydrocarbon accumulation in the basin may be successful if the exploration sites are narrowed down to the regions where moderate heat flow, high sedimentary thicknesses with few shallow seated magnetic sources (intrusives), and elongated geological structures were mapped in this study. •Thermal and geological structures of part of the Chad Basin Nigeria were inferred from magnetic anomalies.•Values of the heat flow range from 75−125mW/m2 and the geological structures dominantly trend E-W, ENE-WSW and NE-SW.•Heat flow in Chungul Buturi and Gumsa areas are sufficient for economic exploitation of geothermal energy.•Dry wells in the basin are most likely a consequence of excessive heat flow during hydrocarbon formation/accumulation.•The basin has a higher potential for gas accumulation than oil.