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.