The Lower Miocene Nukhul Formation (Gulf of Suez, Egypt): microfacies and reservoir characteristics

Abstract

The Lower Miocene Nukhul Formation was deposited during early stages of Gulf of Suez rifting. Outcrop of this formation at Gebel el Zeit, Egypt is up to 100 m (328 ft) in thickness and consists of lower sandstone-dominated and upper carbonate-dominated units. Samples were collected from the Nukhul Formation outcrop in order to describe the lithofacies, mineralogy, and petrographic characteristics to better understand the hydrocarbon reservoir potential of the unit. The investigations showed that the lower part of Nukhul Formation at North Gebel el Zeit consists of poorly sorted, dolomitic sandstone and sandy dolomite which were deposited in a shallow-marine setting. The presence of polycrystalline and crushed quartz grains in Nukhul strata indicates that these strata were sourced by recycled sediments associated with local uplift tied to rifting. The upper Nukhul consists of dolomitized carbonates with preservation of original textures; primary limestone depositional textures include intraclast packstone, rudstone, and coral-algal boundstone, wackestone, and grainstone with minor floatstone. Carbonate rock strata were deposited in shallow marine, peritidal to subtidal environments that developed on faultblock highs. The presence of zoned saddle dolomite suggests some component of fault-controlled fluid flow. Reservoir characteristics of the Lower Miocene Nukhul Formation at the Gebel el Zeit indicates favorable properties for reservoir development in both the lower siliciclastic-dominated dolomite and the upper dolomitized carbonate portions of the formation.

Structural setup of Gara Marine area as deduced from 3D seismic interpretation and gravity-magnetic modelling, Gulf of Suez, Egypt

“…The structural-tectonic framework of the southern Gulf of Suez (Figure 2(b)) was discussed recently by many authors (e.g. Patton et al 1994;Sharp et al 2000;Rohais et al 2016;Bosworth and Durocher 2017;Segev et al 2017;Temraz and Dypvik 2018).…”

Geophysical and hydrocarbon prospect evaluation of Nukhul Formation at Rabeh East oil field, Southern Gulf of Suez Basin, Egypt

“…The lower clastic interval of the Nukhul Formation deposited in shallow marine conditions (Schutz 1994;) and partially filling submarine gullies that transported debris from uplifted areas (Temraz and Dypvik 2018). However, some portions of Nukhul The Early Miocene Nukhul Formation is the first syn-rift rock unit in the in the Gulf of Suez area (Temraz and Dypvik 2018). Its type section located at Wadi Nukhul in the central eastern portion of the Gulf of Suez.…”

“…Its type section located at Wadi Nukhul in the central eastern portion of the Gulf of Suez. It is generally composed essentially of conglomerates, sandstones, shale and marl, limestones and evaporites Temraz and Dypvik 2018). In outcrops at the west of the Hurghada area, the lowermost syn-rift conglomerates referred as the Abu Gerfan Formation (Bosworth and McClay 2001).…”

“…Nukhul Formation is considered the main heavy oil producer from the Early Miocene at the Gulf of Suez region because of its highly fractured nature (Temraz and Dypvik 2018). But it also represents high quality hydrocarbon reservoirs in more than fifteen oil fields at the Gulf of Suez region (Saoudi and Khalil 1984).…”

Source structures at Pre-Miocene level as deduced by gravity stripping

“…Schlumberger 1984;McClay et al 1998;McClay 2001. Sharp et al 2001;Young et al 2002;Jackson 2008;Khalil and McClay 2008;Hewaidy et al 2016;Pietrantonio et al 2016;Rohais et al 2016;Bosworth and Durocher 2017;Segev et al 2017;Temraz and Dypvik 2018) indicated that the stratigraphic section of the GOS basin can be divided into three major units of different thicknesses, depositional environments, areal distributions, and hydrocarbon potentialities. The inside of the GOS consists of Miocene and Post-Miocene rocks while outside the depression, the high relief ridges are built of basement rocks in the southern portion, followed to the north by Palaeozoic-Cenozoic sediments (Figure 1(c)).…”