Reservoir characterization and evaluation of depositional trend of the Gombe sandstone, southern Chad basin Nigeria

摘要

This study attempts a reservoir characterization and evaluation of depositional trend of sands to assess the petrophysical qualities of Gombe sandstone as a potential reservoir unit for hydrocarbon accumulation in the Chad basin. The economic viability in parts of the Chad basin outside Nigeria and other structurally related contiguous basins such as Doba, Doseo, Bongor fields, and Termit-Agadem basin in the Niger Republic have been investigated. The investigations revealed commercial petroleum accumulations which necessitated the need to assess the petroleum potentials of the Nigerian portion of the Chad basin. Four sand units within Gombe formation penetrated by five wells (Ngammaeast 01, Ngornorth 01, Kinasar 01, Ziye 01 and Murshe 01) were delineated, correlated and their continuity estimated across the studied wells. Petrophysical parameters of these sand units such as porosity, permeability, water saturation, hydrocarbon saturation, bulk water volume, etc were computed and interpreted. Net-to-gross (NGR) values of these sand units were also calculated, and NGR maps were contoured for each sand unit. The direction of deposition of the sands was thus inferred to be east- west. The interpretation suggests that Gombe sandstone in Chad basin is a potential reservoir for hydrocarbon accumulation.