Hydrocarbon Prospect Evaluation from Remote Sensed Data in Parts of Lower Benue Trough

Abstract

The search for hydrocarbons in parts of the lower Benue basin has remained comatose because of poor discoveries. The basin has attracted focused attention in the recent because of the continued discovery of commercial hydrocarbons in the contiguous basins of Chad and Niger Republics and Sudan. However, data from drilled wells revealed a number of continuous organic rich stratigraphic intervals with potentials for both oil and gas generation. With the rising global energy demand and uncertainties in supply, explorations are taking new dimensions with the adoption of new technologies. Remote sensing offers an attractive, robust and innovative reconnaissance technique that compliments the geophysical methods in hydrocarbon exploration. In the present study, a satellite image-based analysis was conducted for extracting surface lineaments and terrain attributes for hydrocarbon prospect evaluation in parts of the lower Benue basin. Advanced space borne thermal emission and reflection radiometer global digital elevation model (ASTER GDEM) and Landsat 8 OLI/TIRS data were used. Results revealed that lineament distribution, density and orientation vary across the study area. The tectonic highs (escarpment) have high prevalence of lineaments and lineament density than the lowlands/valleys, suggesting a structurally deformed area. The NE-SW is the most dominant lineament orientation and the major tectonic feature that control the structuration of the study area, while NW-SE, N-S and E-W lineament orientations are less dominant. Terrain attributes were partly lineament-controlled and lithological and could be related to the development of petroleum entrapment structures. Hydrocarbon prospect zones were delineated in medium to high lineament density areas, where lineament intersections and connectivity capable of trapping hydrocarbons is high. Therefore, Agwu, Awka, Enugu, Nsukka, Udi and Ukehe located on the escarpment are preferred prospect areas than Adanu, Nkalagu and Igumale in the flanking lowland/valley areas for detailed hydrocarbon exploration. Correlation of lineament density and surface hydrocarbon seepage in parts of the basin, revealed that high lineament density correlates with known location of hydrocarbon seepage in the study, indicating the connectivity of these lineaments with deep seated structures.