Al-Hikmah University Journal

The Turonian Eze-Aku Formation of Middle Cretaceous age that outcrops on the eastern edge

of the Abakaliki Anticlinorium, Southern Benue Trough, Nigeria, is a possible hydrocarbon

reservoir rock. To assess its reservoir properties, representative outcrop samples of the

sandstone unit of the Eze-Aku Formation were collected and studied. To achieve this

objective, a detailed description of the sedimentological, and petrographic features of the

sandstone unit of the Turonian Eze-Aku Formation were conducted. The most abundant

detrital component in the samples (both polycrystalline and monocrystalline) is quartz

grains, followed by feldspars, as determined by petrographic examination. Quartz comprises

92-93%, feldspar varies between 2% and 3%, and rutile, garnet, and tourmaline occur in

trace amounts up to 1%. The polycrystalline quartz grains are well rounded with varied

crystals boundaries. The sandstone shows moderate to very good sorting with mesokurtic

leptokurtic distribution and an average porosity of 38.4%. The permeability of the sandstone

unit is of 6.2 ×10-3md. The shape and orientation of the sandstone ranges from angular to

sub-angular, rounded to sub-rounded with a ratio of 54.38:34.25 respectively. The samples

are fine skewed while some are very fine skewed. From the results, it shows that most of the

samples are mesokurtic, only a few are leptokurtic which implies that the frequency has zero

kurtosis, and which indicates that the sediments are obtained from multiple sources. The Eze

Aku formation has considerable potential as a reservoir.