Basement Structural Controls on Sedimentation and Hydrocarbon Charge, Nile Delta, Egypt

By

John C. Dolson¹, Paul J. Boucher², Jon Teasdale³, Karen Romine⁴

(1) BP Egypt, Cairo, Egypt (2) BP Egypt, Egypt (3) SRK Consulting, Deakin, Australia (4) SRK Consulting, Deakin West, Australia

 Miocene and Pliocene sedimentation patterns in the Nile Delta are highly asymmetric, characterized by a gentle western and steep eastern flank. The cause of this geometry is a deep Jurassic age rift system extending northeastward from the Western Desert and offshore as far as Cyprus. The position of the Nile Delta itself is controlled by the intersection of this fabric with 1) a NW-SE oriented Precambrian age transform (Moghra high) underlying the western coastline of the Mediterranean 2) the Cretaceous hinge line 3) Syrian Arc structural elements.

The Rosetta fault system is the most prominent of the NE-SW oriented features. The large paleo-high footwall of the Rosetta fault limits accommodation space along the western edge of the Nile Delta, creating a gentle slope facies. The eastward tilt creates the over-steepened eastern side.

A continental to oceanic crust transition west of the Rosetta fault forms a series of “down to the basin” fault blocks. A major relay ramp occurs at the intersection of the Rosetta system with the Moghra High, forming the input point for the Rosetta branch of the Nile. Eastern delta sedimentation patterns are controlled by Syrian Arc structural lows.

The structural and sedimentary fabrics of the Nile Delta owe their geometry to the interplay of these underlying features. Intersections of these older trends with younger lineaments or continued reactivation create favorable focal points for vertical migration of hydrocarbons and coincide with the location of a number of giant fields.