Petrophysical characterization, microfacies analysis, and diagenetic attributes of the Lower Jurassic surface analog sequence in Gebel El-Maghara area, north Sinai, Egypt

Abstract

This study concerns with the petrophysical characteristics of the Lower Jurassic surface analog in Gebel El-Maghara area (from base to top Mashaba, Rajabia, and Shusha formations), north Sinai, Egypt and implementation of the mineral components and diagenetic controls on reservoir characteristics. A full set of petrophysical measurements including porosity (∅He), permeability (k), grain and bulk densities (σg and σb, respectively), and true formation resistivity factor was applied. The Lower Jurassic sequence is subdivided into five hydraulic flow units (HFUs) that consist of three reservoir rock types (RRTs). These RRTs are composed of three microfacies association (MFAs). The RRT1 plug samples consist of the mostly clastic MFA1; they are porous, permeable, and have good reservoir quality that is using the flow zone indicator (FZI), and the reservoir quality index (RQI). The lowest reservoir quality is assigned to the RRT samples which are mostly composed tight carbonates. Based on the petrographical studies, SEM imaging, and the XRD analysis, dissolution and fracturing slightly enhanced the reservoir potentiality of the RRT1 samples, whereas physical compaction, tight cementation, and authigenic clay content (kaolinite, hematite, and goethite) are responsible for deterioration of the reservoir properties of RRT3 samples and reduction of the RRT2 samples.