Elsa Cecconello will present her PhD work that she has done at IFI in collaboration with PGS (Petroleum Geo-Services).
Abstract: Marine seismic surveys are performed under both calm and rough weather conditions. In seismic processing, the sea surface is often considered as a flat reflector, and the effects of different weather conditions are largely ignored. Yet, previous studies have shown that rough-sea-surface ghosts can affect negatively the quality the 4D signal if not handled properly during data processing. There is thus a need to study the effects of realistic weather conditions.
To address these challenges, we derive a modeling tool accounting for realistic sea-surface models. Using the generated time-variant scattered wavefields, we observe a significant impact of the sea-surface time variation on the ghost wavefields. Then, we study the effects of time-varying sea surfaces on source deghosting and multiple removal. We show a weather-dependent error when applying source deghosting. However, by applying the two processes simultaneously, we obtain subsurface reflections free of sea-surface effects for any weather. The latter technique is also tested successfully on an OBC dataset. This study will thus help to extend the usable ship time in adverse weather conditions without loss of data quality.