Petrographic and organic geochemical studies of the Oligocene-Pliocene mud-rich formations, East Mediterranean concession, Egypt

Nineteen ditch samples and rock–eval pyrolysis data taken from Wakar-1 well of Wakar Field and PFM-SE-1 well of Port-Fouad-Marine Field selected for petrographic, elemental, total organic carbon (TOC), and geochemical analyses of the Oligocene-Pliocene mud rich formations (Fms). They differentiate in studied wells from base to top into Tineh Fm (Oligocene), Qantara Fm (Lower Miocene), Sidi Salem Fm (Middle Miocene), Wakar Fm (Upper Miocene), Rosetta Fm (Upper Miocene), and Kafr El-Sheikh Fm (Pliocene). Petrographic analysis of Kafr El-Sheik samples shows that vitrinite is very common (52.03%), inertinite is common (42.74%), and liptinite is rare (5.32%). The same samples reveal a depositional setting within the shelf of proximal and distal depositional settings of suboxic-anoxic and dyoxic-oxic conditions. TOC, S1, S2, and production index (PI) of the studied formations show a poor to a fair quantity of OM. All the formations are dominated by terrestrial type III kerogen of mainly poor gas-prone potential. The maximum threshold of the relative hydrocarbon potential (RHP) curve is recorded at depths of 2600 m and 4650 m in Wakar well and shallowing to be at 1500 m and 3300 m in PEM-SE-1 well of either biogenic and thermogenic hydrocarbon (HC) generated peaks. The heat flow calculated in the present wells shows a gradual increase from 74.34mW/m2 (Wakar-1) to 80.93mW/m2 (PFM-SE-1) from the NW to SE direction. A sedimentary/subsidence (SED/SUB) ratio of value 1. The burial history diagram of the Wakar-1 well reveals that the Oligocene to Upper Miocene Formations of Tineh, Qantara, Sidi Salem, and Wakar are entering the early oil generation stage since 3.4 Ma and have not proceeded to the peak stage of oil generation yet with a slight increase in maturity toward the SE direction.