Source Deghosting and Demultiple for Calm and Rough Weather Conditions

Abstract

Source deghosting and demultiple algorithms have been extensively studied but mostly in the case of a flat sea-surface. In this work, we consider time-varying sea-surfaces in different types of weather conditions and derive an inversion approach for removal of sea-surface effects. Starting from Rayleigh’s reciprocity theorem, we model seismic data including time-dependent wavefields scattered at the sea-surface, and highlight the temporal variation of these wavefields through simple synthetic examples, comparing two different weather conditions (calm and rough). We also reveal a limitation of source deghosting in the context of time-dependent wavefields: source deghosting affects the sea-surface multiples and can compromise the success of demultiple processing, which is applied in a later step. Results shows that this limitation is also important under calm weather conditions. To overcome this limitation, we propose simultaneously source deghosting and demultiple, therefore, removing all sea-surface effects in one-step. Synthetic data examples are shown using the Sigsbee2B geological model.