Rejuvenating exploration opportunities in Egypt's Mediterranean region using basin-scale 3D seismic reprocessing and subsurface evaluations

Abstract

The Eastern Mediterranean region has proven to be a key province for natural gas resources over the last two decades. Gas discoveries in the Nile Delta Basin, Levantine Basin, and over the Eratosthenes platform have proven that an efficient working petroleum system extends to the deepwater areas and into the distal parts of the Nile Delta and Levantine basins. While the suprasalt biogenic post-Messinian play is adequately imaged in various areas in the Eastern Mediterranean region, seismic imaging of the deeper subsalt pre-Messinian plays is challenged by legacy seismic acquisition and processing techniques. Moreover, the complexity of the Messinian salt structures and the heterogeneity of the lithology of the Messinian layer across the Mediterranean basins represent a key subsurface challenge. In phase 1 of the study presented in this paper, we reprocessed 12 legacy 3D seismic data sets over 12,000 km2 and constructed a consistent basin-scale earth model from the shelf areas offshore Sinai to the deepwater areas around the Zohr carbonate platform. The data processing and imaging sequences incorporate full-waveform inversion and tomography in the earth model building process followed by a basin-to-lead evaluation to delineate exploration opportunities in phase 1. The evaluations resulted in delineating Cretaceous and Oligo-Miocene untested structures. Furthermore, potential deepwater Lower Miocene sand fairways were outlined, supported by improved regional seismic imaging and consistent seismic attributes over multiple legacy surveys. The authors of this paper expect to update the results of their work after completing the earth model building and the prestack depth migration workflows of an additional 13 legacy surveys over 35,000 km2 in phase 2 of the study.