Seismic interpretation of the Aptian Alamein Dolomite in the Razzak oil field, Western Desert, Egypt

The Razzak oil field lies in the northern part of Abu Gharadig Basin (northern part of the Western Desert). Aptian Alamein Dolomite is a reservoir rock, in which the oil is trapped in the fractures of the dolomite, depending on structural framework affecting it. The Razzak field structure is one of the most complex structures in the Western Desert of Egypt. The integration of borehole data and 3D seismic interpretation shows that the Jurassic forms a horst block separating the Razzak field into north and south Razzak fields. This horst block is bounded on the southeast by NE-SW trending normal faults (sigma fault) and on the north by several normal faults which step down into the Alamein Basin to the north. The behavior of the sigma fault gives a new concept that the migration of hydrocarbons from the south to the north direction could not be sealed by the NE-SW horst block. Time-and depth-structure maps of Alamein Dolomite illustrate different structure features that play an important role in the hydrocarbon potentialities and prospect identification in the area. One primary component of exploration and development success is to identify the faults that provide structural closure and traps. Two main faults run in the NE-SW direction and form a pattern of horst and graben blocks. In addition, NW-SW trending faults cut these blocks and form a right-lateral strike-slip component of displacement. Four-and three-way dip structural closures represent the fruitful locations for high production and new prospect wells in the Razzak oil field and other similar setting elsewhere.