KHALIL, MESBAH, Gulf of Suez Petroleum Company, Cairo, Egypt

ABSTRACT: Structural Evolution of the "B" Trend and its Significance for Hydrocarbon Exploration in Offshore Gulf of Suez, Egypt

The "B" trend is one of the important structural trends in the southern part of the Gulf of Suez. Located 250 km southeast of the town of Suez, this trend includes seven oil fields: Amal, Wali, GS 365, Sidki, East Zeit, Hilal, and Ashrafi.

The present study was done to study the structural development of the B trend, through integrating data from 70 wells drilled in the area with seismic interpretations and the interpreted structural pattern of the rifted blocks mapped in outcrop. Results of this study indicate that the B trend consists of a series of faulted and southwesterly dipping sub-blocks. The predominate strike direction is northwest-southeast. In the early rifting phase (Late Eocene-Oligocene) the previously mentioned subblocks were believed to have been composed of a single major fault block, which had a northwest strike and a gentle dip toward the southwest. This huge block was bounded to the east by a large zigzag fault. The intermittent extension rift tectonics that continued throughout the Miocene caused t e breakdown of the huge B trend block into the present substructures. This breaking down occurred using two preexisting directions of fractures, which were oriented northwest and north-northeast. This interpretation concurs with the synthetic transfer rift model and explains the prismatic to rhombic geometry of the B trend subblocks. The north-northeast faults acted as hinges (rotation planes) for the B trend block, which consequently responded separately with the intermittent extension tectonics. Some subblocks were tilted more than others. This rotational movement provided the lateral strike separation between the subblocks, juxtaposition of the impermeable seals against the reservoir rocks, and created the separate oil fields that are characterized by different oil water contacts.

AAPG Search and Discovery Article #90990©1993 AAPG International Conference and Exhibition, The Hague, Netherlands, October 17-20, 1993.