Reservoir-scale petrographic and grain size study of Bida basin sandstones: A geophysical perspective on porosity and depositional trends

Abstract

This study investigated the granulometric and petrographic characteristics of siliciclastic sediments in parts of the Northern Bida Basin, with the aim of evaluating their influence on porosity, permeability, and hydrocarbon storage potential through aeromagnetic and sedimentological analyses The objectives are to: (i) determine area of low magnetic intensity, (ii) determine the grain size distribution, (iii) assess petrographic features, (iv) determine the heavy mineral composition, and (v) delineate the possible areas for good porosity and permeability. The study revealed that: (i) the sandstones are characterized by coarse to very coarse grains, with moderate to poor sorting, and exhibit a very leptokurtic distribution, indicating a good reservoir quality due to high porosity and permeability; (ii) the bivariate plots reveals that the sediments are primarily of fluvial and beach origin; (iii) the petrographic analysis indicates dominance of quartz amongst the constituents, which reflects a mature sediment source; (iv) the sediment exhibits a mixed origin; and (v) Kutigi and Bida locations appear to have the best potential for hydrocarbon storage due to their better sorting and grain distribution, leading to improved permeability. The study concluded that the Bida Basin showed hydrocarbons with key petroleum elements, though immature source rocks limit generation. The study, therefore, recommended detailed characterisation of petroleum system elements and reservoir quantification for further studies to achieve a comprehensive hydrocarbon prospectivity of the basin.