Abstract

Conventional marine exploration offshore Nile Delta is challenged by shallow heterogeneities and a deep, complex anhydrite layer called the Messinian. These subsurface complexities cause variable illumination and strong diffracted multiples resulting in imaging challenges below the anhydrite on conventional narrow-azimuth towed streamer acquisition because the recording antenna is too small (Figure 1a). Additionally, it has proved difficult to build the detailed depth migration velocity model required to correctly image below the Messinian layer. Multi-azimuth (MAZ) acquisition using time-domain processing however, has been very successful in addressing both the noise and illumination problems in the Nile Delta. The increased azimuthal and crossline offset coverage—bigger antenna—is achieved by acquiring six conventional marine surveys over the same area at 30° sail-line increments (Figure 1b).

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