SUBSURFACE STRUCTURAL INTERPRETATION OF PARTS OF SOUTHERN BENUE TROUGH, NIGERIA USING AEROMAGNETIC DATA IMPLICATIONS FOR HYDROCARBON POTENTIAL

Abstract

This study aimed at carrying out subsurface structural interpretation of parts of southern Benue Trough, Nigeria using aeromagnetic data for implications for hydrocarbon potentials. The study area is bounded by latitude 8^o00^l N to 9^o00^l N and longitude 9^o00^l E to 10^o00^l E with an area extent of 12,100 km². The methodology involves the use of four aeromagnetic data sheets namely; 211 (Kwolla), 212 (Shendam), 232 (Akiri) and 234 (Ibi) which were collected from Nigerian Geological Survey Agency and the data were contoured and analysed using Oasis-Montaj, Surfer and GeoRose softwares. The visual assessment of total magnetic intensity and residual anomaly maps of the study area reveal magnetic intensities ranging from -39.0 nT to 154.4 nT. The 3D surface map of the magnetic intensity of the basement reveals the presence of uplifts and depressions, a typical expression of folds. The result of qualitative interpretation of magnetic maps also reveals that the area is intensely faulted with major faults trending in northeast to southwest (NE-SW), whereas, the east to west (E-W) and northwest to southeast (NW-SE) are the minor trend in the area, which align with the major rift system of Benue Trough. The spectral analysis of the potential data revealed sedimentary thickness ranging from 0.47 km to 5.88 km with an average of 2.03 km, which could be investigated for further petroleum exploration. The generated geological model results revealed two geological layers in the area, namely the sedimentary layer and the basement layer. The result shows that the temperature at depth values obtained range between 39.95 ^oC and 167.56 ^oC with an average of 76.71 ^oC and they are shallower at the northern areas than the other areas. The study concludes that the southern and central parts of the study area are good for possible hydrocarbon accumulation in the region.