Basement configuration and lineaments mapping from aeromagnetic data of Gongola arm of Upper Benue Trough, northeastern Nigeria

摘要

The petroleum prospect evaluation of the Gongola arm of the Upper Benue Trough in the northeastern part of Nigeria has been undertaken through the analyses of High Resolution Aeromagnetic data (HRAM) acquired over the basin, with a view to determining sections of the basin having basement geometry, sedimentary thickness and structural framework among others that could support generation and preservation of the hydrocarbon resource. Processed, transformed and enhanced Total Magnetic Intensity (TMI) data were subjected to various analyses to define terrain geology, extract lineaments and delineate basement geometry, which were subsequently employed to generate basement model and structural framework of the basin. Most of the extracted lineaments trend ENE - WSW direction while Analytic Signal - Euler Deconvolution depth-weighting generate solutions which range in sediment thickness from 50 m above to over 5 km below the Minna reference datum, thus presenting undulating basement topography. Three sub-basins having depths in excess of 3 km, separated from each other by infra-basin subsurface basement highs, were delineated. The coexistence of considerably thick (3-5.7 km) sedimentary rock units and underlying structurally active basement rocks, assured geothermal gradient for organic matter maturation and guaranteed trapping of generated oil and gas within reservoirs' structural traps.