IOSR Journal of Applied Geology and Geophysics (IOSR-JAGG) e-ISSN: 2321–0990, p-ISSN: 2321–0982.Volume 8, Issue 6 Ser. I (Nov. – Dec. 2020), PP 10-16 www.iosrjournals.org DOI: 10.9790/0990-0806011016 www.iosrjournals.org 10 | Page Reservoir Characterization of the Eze-Aku Formation, Lower Benue Trough, South-Eastern, Nigeria Haruna, K.A. 1* , and OJo, O.J. 2 1. Al-Hikmah University, Ilorin, Nigeria. 2. Federal University Oye-Ekiti, Ekiti State. Abstract The TuronianEze-Aku Formation of the Middle Cretaceous which outcrops at the eastern flank of the Abakaliki Anticlinorium, Southern Benue Trough Nigeria represents a potential reservoir rock for hydrocarbons. Representative outcrop samples of the sandstone unit of the Eze-Aku Formation were collected and analyzed in order to determine its reservoir characteristics. In order to achieve this aim, a comprehensive description of the sedimentological, geotechnical and petrographical characteristics of the sandstone unit of the TuronianEze-Aku Formation was carried out. Petrographic analysis shows quartz grains are the most abundant detrital components in the samples (both polycrystalline and monocrystalline), followed by feldspars. Quartz constitutes about 92-93% and feldspar ranges between 2-3% while rutile, garnet and tourmaline occur in trace quantities to about 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 -3 md. 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 this implies that the frequency has zero kurtosis and which indicates that the sediments are obtained from multiple sources. Keywords: reservoir,porosity, permeability, kurtosis, --------------------------------------------------------------------------------------------------------------------------------------- Date of Submission: 28-11-2020 Date of Acceptance: 14-12-2020 --------------------------------------------------------------------------------------------------------------------------------------- I. Introduction The TuronianEze-Aku Formation of the Middle Cretaceous which outcrops at the eastern flank of the Abakaliki Anticlinorium, Southern Benue Trough Nigeria represents a potential reservoir rock for hydrocarbons (Fig. 1). This study investigates the reservoir characteristics of the sandstone units of the Eze-Aku Formation using selected outcrop. Outcrop analogue studies in reservoir characterization have been demonstrated to be a powerful tool, supplementing sparse subsurface data and are commonly used to develop quantitative descriptions of sandstone architecture and rock properties at the reservoir scale (Dutton et al, 2000). The main aim of this study is to provide detailed analyses on the reservoir characteristics of the TuronianEze-Aku Formation. Indeed, despite the numerous documented works on the sedimentology, petrographic and depositional environment of the TuronianEze-Aku Formation (Igweet al., 2013; Ikoro D. O., 2014), currently only limited information is available on its reservoir characteristics. This limits our ability to understand its reservoir qualities. Consequently, this study is built upon these concerns and aims at providing a comprehensive understanding of the reservoir qualities of the sandstone unit of the TuronianEze-Aku Formation. In order toachieve this aim, a comprehensive description of the sedimentological, geotechnicaland petrographical characteristics of the sandstone unit of the TuronianEze-Aku Formation was carried out in order to investigate the tectonic setting,sediment transportation processes,source rock origin, and itsreservoir quality of the study. Results shows sandstones unit of Eze-Akucan be classified as a quartzarenite and quartz grains are the most abundant detrital components in the samples (both polycrystalline and monocrystalline)