ABSTRACT: Tectonic inversion and sedimentary basins development: an impact on hydrocarbon potential, onshore west Nile Delta, Egypt

Eid, Ahmed¹, Mohamed Darwish², and Sami Shaheen¹
(1) EGPC, Maadi, Cairo, Egypt
(2) Cairo University, Giza, Egypt

The concerned region includes Palaeozoic to Tertiary subsurface sequence of > 15000' thick from which only two oil fields were discovered. Interpretation of the available seismic lines and the reconstructed seismic structural depth maps and structural cross sections proved that the area is characterised by a complex tectonic framework. Initially it has been affected by extensional phase of Jurassic-Early Cretaceous rifting. Afterwards during Late Cretaceous time, the tectonic inversion took place. Combination of isopach and structure depth maps illustrates that the area is seen as a major syncline with its axis aligned in a NE-SW direction. The Jurassic depocenter was at the central part receiving > 9000' sediments. During the Early Cretaceous, it was shifted and fluctuated from Northwest (Barremian of > 2000' thick) to the Southwest (Aptian/Albian of > 3200' thick). As a result of this complex tectonic, the area could be distinguished into three domains, Natrun basin in the north as mirror image of El Gindi basin in the south cut by Kattaniya inversion in the centre. Source rock data based on R₀ analysis indicates that the maturation levels for oil expulsion is at relatively shallow depth in the Kattaniya inversion as compared to the Natrun basin. Thermal burial history was applied for Kattaniya inversion and Natrun basin. It indicates that the Middle Jurassic organic rich Khatatba Formation is, at present, the main oil generation and the post-Khoman event is the time of hydrocarbon migration. The main traps are faulted closures, whether faulted nose or faults on four-way dip structure (faulted anticline).

AAPG Search and Discovery Article #90913©2000 AAPG International Conference and Exhibition, Bali, Indonesia