SUBSURFACE STRUCTURAL ANALYSIS USING AIRBORNE GRAVITY DATA AND ITS IMPLICATIONS FOR HYDROCARBON EXPLORATION IN KOGI STATE, NIGERIA

Abstract

Airborne gravity data of Kogi State, Nigeria, obtained from the Bureau Gravimétrique International (BGI), has been interpreted to identify subsurface structural features and assess their implications for hydrocarbon potential in the region. The residual Bouguer gravity anomalies extracted from the field data were processed using first-order filtering techniques and gridded to generate a Bouguer gravity map. Selected points across the state were further analysed through contouring, forward and inverse modelling, and Euler depth estimation, using Oasis Montaj software. The interpretation reveals Bouguer gravity values ranging from -13.4 mGal to 44.2 mGal, indicating variations in subsurface density distributions. Low gravity anomalies, corresponding to low-density subsurface formations, were observed in the southwestern, southeastern, northwestern, and northeastern areas of the state. Conversely, high-density formations were identified in the southwestern, northern, and central regions. The dominant subsurface structures include faulted synclines and anticlines, with structural trends oriented southwest-northwest in the north, east-west and north-south in the central regions, and southeast in the southeastern zone. Sediment thickness, which also reflects the depth to basement rock, ranges from 53.7 m to 8,890 m. These sediment depths suggest favourable conditions for hydrocarbon generation, while the identified structural formations provide suitable potential reservoirs for hydrocarbon accumulation. Based on these findings, further detailed geophysical surveys are recommended to fully explore the hydrocarbon prospects of Kogi State.