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.