The Effect of Strike-Slip Motion on Hydrocarbon Entrapment in Southern Province of the Gulf of Suez
By
Medhat Hassan Aly1, Iman Hussein Helal1, Selim A.Hamid El Srogy1
(1) Geisum oil Co, Cairo, Egypt
Geisum and Tawila fields lie in the southern entrance of the Gulf of Suez,
south to the Morgan hinge zone, where the fault blocks are commonly tilted to
the south-west. The structure configuration is interpreted from 3-D seismic for
both fields as north-west tilted fault blocks, which are dissected and bounded
by sets of clysmic faults having various magnitudes of throws. The structure is
segmented by sets of cross-faults showing dextral strike-slip motion in the
Geisum field and sinistral in the Tawila. The major cross-fault in Geisum field
divides the structure into two blocks; the southern and the northeastern. The
large lateral displacement of this major fault brings the thick preserved
pre-Miocene in the northeastern block
to juxtapose the fractured granitic
basement in the crestal area of the southern
block
. In both blocks the main
reservoirs are the Cretaceous sandstones and the fractured Precambrian basement.
Oil was recently discovered in the well developed Middle Eocene (Thebes
Formation), while in the southern
block
the equivalent section of Middle Eocene
was found water-bearing. In the Tawila field, the major cross fault separates
the field into southern and northern blocks. In the southern
block
, oil was
found in the Miocene Kareem and Belayim Formations, while in the northern
block
which is in a higher structural position, the Miocene sand was water bearing.
The geochemical study suggested that Miocene reservoir had been charged from the
basin located south of the Tawila field. This reveals the role of strike-slip
motion in creating a new oil trap in the study fields, thus encouraging further
exploration in the vicinty.