Preliminary assessment of the Cambro-Ordovician reservoir potential from the Shushan basin, north Western Desert, Egypt

Abstract

This study presents the first-ever preliminary assessment of the potential reservoir intervals from the Cambro-Ordovician Shifah Formation of the Shushan Basin, Western Desert. Seismic data , thin sections, XRD, XRF , and wireline logs were integrated to characterize the potential intervals. The study area is characterized by E-W and ENE-WSW trending steeply dipping normal faults creating a series of horsts, grabens , and half-graben structures. Based on the wireline logs-based petrophysical assessment, three potential reservoir intervals are identified with the Shifah Formation below 15000 ft depth. All the promising intervals show little shale volume (10–20 %) and 70–80 % hydrocarbon saturation, but the porosity is dominantly below 10%. The two potential sandstone intervals are composed of quartz arenites affected by silica cementation and mechanical compaction. These glauconite-bearing sandstones exhibit low-angle cross-lamination and planar lamination, likely deposited in a fluvial to shallow marine depositional environment . Both the tight sandstone intervals exhibit E-W, and NW-SE striking, closed, and partially open fractures which can contribute to the reservoir flow capacity. The third potential reservoir interval is an igneous intrusive body, composed of alkali syenite and exhibits secondary intraparticle porosity due to partial feldspar dissolution and minor fractures. The preliminary assessment presented in this work shed critical insights into the reservoir potential of the Shifah Formation. • Fist preliminary assessments of potential Shifah reservoirs are presented. • Out of three potential targets, two are quartz arenite and third one is alkali Syenite igneous body. • Identified intervals are tight but exhibits high hydrocarbon saturation. • Presence of partially open fractures confirmed from the image log.