Online Journal for E&P Geoscientists

Laake, Andreas ¹; Sheneshen, Mohamed ^*1
(1) WesternGeco, Cairo Heliopolis, Egypt.

Structural mapping on the western gravel plains of the Gulf of Suez is challenging because of complex rift tectonics. Two main fault systems are observed : the NW-SE trending rift-parallel faults and SW-NE trending cross-rift faults. Rift-parallel faults show a clear impedance signature in seismic data and can be mapped through processing the seismic cube for heterogeneities. The outcrops of these faults are also mapped and satellite imagery interpreted for lithology.

Cross-rift faults, however, are not associated with a seismic impedance contrast and require a different approach. We noticed that present wadi courses are affected by the cross-rift faults and assumed that this observation would also hold for palaeo-wadis. We used satellite imagery to map a recent wadi and to generate the template for a geobody. The seismic data cube is then processed for instantaneous frequency to detect local resonances associated with palaeo-wadis and to associate geobodies with the palaeo-wadi courses. We could distinguish between the braided stream sections of the wadi courses, the spatial boundaries of which allowed us to infer the delimiting cross-rift fault and we found palaeo-deltas, which allowed the delineation of the palaeo-coastline.

In the final step we merged the fault plains from the rift-parallel system and the cross-rift system and correlated it with the fault outcrops delineated from interpreted satellite imagery. The integration of satellite imagery interpretation with seismic data processing allowed the delineation of structural trends with very different geophysical properties and resulted in a complete structural description of this complex rift environment.