The Effect of Transfer Faults in Shaping a Major Hydrocarbon Trap - October Field, Suez Rift, Egypt

By

 Tamer Mohamed Reda¹

(1) Department of Geology, Ain Shams University (presently at Gulf of Suez Petroleum Company), Cairo, Egypt

 October field, in the Gulf of Suez, Egypt, is one of the largest oil fields in the basin, with nearly 1 billion barrels of oil reserves. The field is controlled by north-northwest striking, rift-parallel faults as well as northeast and northwest striking transfer faults. It consists of a number of linked, northeast dipping fault blocks and is bounded by a major rift-parallel normal fault which dips to the southwest. The northern end of the field is bounded by a northwest dipping transfer fault. The southern side of the field is bounded by a southwest dipping transfer fault.

The northern and southern transfer faults define the structural geometry of October Field. The major pre-rift reservoirs are brought below the oil water contact on the downthrown sides of these faults. In addition, the growth and timing of fault linkage has strongly controlled syn-rift sedimentation on the flanks and within the field. Syn-rift rocks are thicker and more sandstone-rich on the downthrown sides of some transfer faults, where they are also locally fault-juxtaposed against oil accumulations in pre-rift reservoirs, creating additional oil accumulations. Structural and syn-rift stratigraphic relationships around October field provide excellent analogues to other traps in the Gulf of Suez basin and rift basins worldwide.