Abstract

The northern Red Sea area hosts a classic triple junction of the Red Sea, Gulf of Aqaba, and Gulf of Suez rifted basins. The sedimentary succession here can be divided into prerift (pre-Miocene) and synrift (Miocene and post-Miocene) megasequences. The prerift section has been penetrated in only a few wells drilled on the western (Egyptian) side of the Red Sea, whereas the synrift section is known on both the Egyptian and the Saudi sides of the Red Sea. Although the synrift units on both sides of the water are similar in facies, thicknesses, and depositional environments, they have different stratigraphic nomenclatures. The northern Red Sea consists of elongated troughs separated by elongated structural highs, both of which trend northwest-southeast (Gulf of Suez trend). These highs are dissected by cross elements trending northeast-southwest (Gulf of Aqaba trend) and east-northeast-west-southwest, and are looked upon as strike-slip faults dislocating these highs. Identified rich source rocks are present in the upper Senonian carbonates, the Sudr and Duwi formations on the western side of the sea, the early Miocene Rudeis Formation (Burqan Group), and the middle Miocene Kareem and Belayim formations (Maqna Group). The pre-Miocene and the early Miocene source rocks host oil-prone kerogen, whereas the middle and late Miocene source rocks contain oil- and gas-prone kerogen. All of these source rocks are sufficiently mature in most of the deep hydrocarbon kitchens to generate hydrocarbons. Using both bulk and specific parameters, the correlation of liquid hydrocarbons and source rock extracts from the northern Red Sea suggests three scenarios. (1) The Egyptian and Saudi Red Sea oils form one genetic family that is different from the typical Gulf of Suez oils. The Gulf of Suez oil is sourced from the upper Senonian carbonates, but the northern Red Sea oil (Egyptian and Saudi) is sourced from the lower Miocene Rudeis Formation and the middle Miocene Kareem and Belayim formations (Burqan and Maqna groups, respectively). (2) The northern Red Sea oil group is characterized by a relatively higher wax content, low sulfur content, a pristane/phytane ratio of more than 1.0, a dominance of C 29 steranes, and an abundance of the biomarker gammacerane; the interpretation of these parameters suggests the possibility of two sources for these oils: a siliciclastic marine source and a relatively restricted, nonmarine source. (3) Both the Gulf of Suez oil group and the Red Sea oil group may mix in one field.

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