Detailed Surface Multiple Prediction Using Split-spread Broadband Seismic Marine Data in a Complex Sea Floor Environment

Hydrocarbon prospection with seismic data on Barents Sea can be difficult to interpret because of severe contaminations of the sections by diffracted multiples residual noises often located above the objectives. Those diffracted multiples mainly result from significant scars of the sea floor produced by paleo-iceberg drifts during glacial ages. To mitigate this problem, a new marine seismic design has been developed which consist into a split-spread geometry where three different shot locations are located on the middle of the spread while acquiring broadband seismic signals. It allows for improved subsurface illuminations allowing for sharp and detailed representation of ground reflectors, including the sea floor. We used several multiples models in simultaneous adaption procedures, including 3D SRME models, but also 3D wave-equation based multiple modeling to fully benefit from those available rich subsurface reflectivity representations. On top of that, an innovative and specific implementation of WE modelling allowed for building diffracted multiples “only” models, into separated datasets for feeding the multi-model adaptive subtractions while preserving primary information (specially low frequencies) with AVO-driven primary models. The ensemble lead to unseen and improved demultiple results on those difficult areas.