STRUCTURAL EVOLUTION OF THE SOUTHERN GULF OF SUEZ RIFT: IMPLICATIONS FOR HYDROCARBON EXPLORATION IN A MATURE BASIN

The southern part of the Gulf of Suez is a unique structural province, as it represents one of three half grabens, that make up the asymmetric Suez rift, which extends from Suez in the north to Hurghada in the south. Different stratigraphic units ranging in age from Paleozoic to Cenozoic are recorded and preserved in the half-grabens, with a variety of depositional environments, thicknesses and facies. Significant syn-rift and pre-rift reservoirs do exist in the Southern Gulf of Suez fields, with multi million barrels of resources. The Gulf of Suez basin is considered mature, as it has been the focus for hydrocarbon exploration and production since the beginning of the twentieth century, and presently lacks significant discoveries in the last decade, which supports the term mature basin. Even though it is a mature basin, the humbling experience of drilling a dry hole still do exist on some structures, particularly in the study area, due to poor seismic imaging and lock of structural restorations. Recent exploration activity has resulted in surprises, due to erosion of the crests of fault blocks. Knowing the timing of rotation on these blocks is of prime importance, since the main resources in these fields are within the potentially eroded pre-rift section. The integration of the surface and the subsurface data sets represented by 5 surface sections, 35 wells, and 400 km2 of 3D seismic data, enabled the reconstructions of the geologic cross sections to be performed, allowing insight regarding fault timing, evolution and reservoir preservation on the tilted blocks' leading edges. The work methodology was made through a series of well correlation panels, using wire line logs of all the syn-rift and pre-rift stratigraphic units to identify the missing sections and attribute them to either faults or unconformities. Constructing isopachs for the sedimentary section, Miocene subcrop mapping along with the 3D seismic mapping, allowed the construction of structural sections that were restored and balanced at different startigraphic levels to reveal fault history, amount of block rotation and preservation of the pre-rift section at the updip edges of the fault blocks. The restoration process helped in better understanding of the tectonic evolution, which has an impact on the hydrocarbon exploration, as it helps in predicting the reservoir presence at the edges of tilted blocks and defining the trap geometry