*1.2.7. Bilqas formation (Holocene)*

corresponds to a lower neritic slope environment. Sidi Salem Formation is unconformably

Abu Madi Formation is composed of interbedded sandstones and mudstones. This formation was deposited as an incised valley fill at the end of the Late Miocene. The depositional environment of Abu Madi Formation changes from fluvial to lagoonal with marine influence

Kafr El Sheikh Formation consists of mudstone sequence with thin limestone and sandstone interbeds. This formation extends all over the Delta area. In the Nile Valley it is accumulated at outer neritic to upper bathyal water depths, following a major lower Pliocene transgression resulted in the flooding of the former Eonile canyon and transforming it into a long, narrow gulf far south Aswan [12]. Rizzini et al. [4] suggested that-the Kafr El Sheikh Formation is accumulated as neritic mudstones on the present onshore delta- and in a basinal setting offshore. They suggested that the sands incorporated into this formation are essentially storm

The Plio- Pleistocene sequences are represented by the following formations.

**Figure 3.** Lithostratigraphic succession of Northern Nile Delta, Egypt modified from Kamel et al. [8].

sands. This formation is conformably overlain by El Wastani Formation.

overlained by Abu Madi Formation.

*1.2.3. Abu Madi formation (Late miocene)*

*1.2.4. Kafr El Sheikh formation (Early–middle pliocene)*

increasing upward.

30 Advances in Petrochemicals

Bilqas Formation is the top sedimentary cover of the Nile Delta province. It consists of sand interbedded with clay rich in pelecypod, gastropod and ostracod fragments. The clays contain many fragments of vegetal matter and peat deposits. The deposition occurred most likely in lagoons and brackish swamp, interrupted by beach sands.

During the last two decades, the Nile Delta and the offshore Mediterranean Sea have been intensively investigated by the petroleum industry. Till now over 36 TCF of gas have been discovered since drilling began in 1966 [13]. The geologic history of the Nile Delta created multiple source, reservoir and seal combinations. Main source rocks are believed to occur in Late Mesozoic and Oligocene to Miocene sedimentary succession.
