Interpretation analysis from satellite gravity data to image the upper lithospheric patterns and their hydrocarbon significance in Sokoto Basin, Nigeria

Abstract

Meaningful exploration and comprehensive geological evidence have been made by the analyses of satellite gravity data for defining the basin’s tectonic framework, subsurface structures as well as delineating favourable regions of hydrocarbon prospect for further appraisal. A digitized composite satellite gravity data covering some parts of Sokoto Basin were acquired and processed to interpret the Bouguer anomalies over the area and to equally image the upper lithospheric patterns beneath the Sokoto Basin and its surroundings. We aim to understand the structural styles of crustal extension in some parts of the Sokoto Basin. Regional and residual gravity components, these were obtained by least-square fitting of a third-degree order polynomial surface to the Bouguer anomaly. The residual anomalies feature NE-SW gravity lows attributed to sedimentary in-fill about the localities of Argungu, Yauri, Koko and Jega, Kamba, Bagudo, Tambuwal, Goronyo, Gada as well as Kolmalo. Data enhancement techniques such as first vertical derivative, total horizontal derivative (THDR), analytic signal, spectral depth analysis, and the standard Euler deconvolution (SED) were applied to enhance deep-seated structures. Results from the qualitative analysis of spectral depth revealed that the average thickness of the sediments varies from 1.679 km to 4.181 km, outsized enough for hydrocarbon prospect. The derivative maps revealed parallel to sub-parallel trending NW-SE, E-W fracture zones within the sedimentary in-fill underlying the study area, coinciding with the cretaceous zones. Hence, the identified lineaments (faults or lithologic contacts) and structures in the area can be attributed to the tectonic setting of the area and probable migratory routes for hydrocarbon migration. More detailed ground gravity and seismic studies may lead to discoveries of structural or stratigraphic traps. We conclude that the area is a promising prospect in terms of oil and gas prospecting.