Structural interpretation of High-resolution aeromagnetic data over the Dahomey basin, Nigeria: implications for hydrocarbon prospectivity

Abstract

The renewed quest to boost Nigeria’s dwindling reserves through aggressive search for oil and gas deposits in Cretaceous sedimentary basins has re-ignited the need to re-evaluate the hydrocarbon potentials of the Dahomey Basin. Aeromagnetic data are a low-cost geophysical tool deployed in mapping regional basement structures and determination of basement depths and sedimentary thickness in frontier basin exploration. In this study, high-resolution aeromagnetic (HRAM) data covering the Dahomey Basin Nigeria have been interpreted to map the basement structural configuration and to identify mini-basins favorable for hydrocarbon prospectivity. The total magnetic intensity grid was reduced to the equator (RTE) and edge detection filters including first vertical derivative (FVD), total horizontal derivative (THDR), tilt derivative (TDR) and total horizontal derivative of upward continuation (THDR_UC)) were applied to the RTE grid to locate the edges and contacts of geological structures in the basin. Depth to magnetic sources were estimated using the source parameter imaging (SPI) method. Data interpretation results revealed shallow and deep-seated linear features trending in the NNE-SSW, NE-SW, NW-SE and WNW-ESE directions. The SPI map showed a rugged basement topography which depicted a horst-graben architecture on 2D forward models along some selected profiles. Two mini-basins ranging in basement depths between 4.5 – 6.3km were mapped offshore of the study area. It appears the offshore Dahomey Basin holds greater promises for hydrocarbon occurrence due to the presence of thicker succession of sedimentary deposits in the identified mini-basins.

Geochemical characterisation of the Turonian-Maastrichtian bituminous sands in Dahomey Basin, Southwestern Nigeria

“…Its tectonic evolution allows the stratigraphic sequence to be divided into three sequences: (1) Precambrian to Triassic intra-cratonic rocks and Jurassic to lower Cretaceous, Continental to marginal marine rocks representing the pre-transform stage; (2) Lower Cretaceous to late Albian rocks representing the syn-transform stage and (3) Cenomanian to Holocene rocks representing the post-transform stage (Boboye and Nzegwu, 2014; Boboye and Omotosho, 2017). Several works of literature documented the different aspects of the geology of the basin, some of which include Murat (1972), Adediran and Adegoke (1987), Omatsola and Adegoke (1981), Onuoha and Ofoegbu (1988), Nton et al (2006), Bolaji et al (2020) and Okoro et al (2021).…”