Migration of free-surface-related multiples: Removing artefacts using a water-layer model

• A new artefact removal approach is proposed for migration of multiples.
• The prediction of migration artefacts uses the water-layer model.
• Removing artefacts by matching subtraction excluding high-reflective interfaces.
• The only additional information required is the water-layer model.
• Numerical experiments are successful in the artefact removal.

The migration of free-surface-related multiples has been developed for seismic data processing because such multiples can be utilised for imaging and sometimes provide additional subsurface illumination. Recently, the simultaneous migration of primaries and free-surface-related multiples has been proposed as an attractive approach for avoiding the costly prediction of multiples. However, the migration artefacts of multiples, generated by mismatched events, pollute the stacked image and degrade the image quality. We developed a new approach to attenuate the distinct migration artefacts of multiples using water-layer-related multiples. In addition to the original data, the only additional information required by this approach is the water-layer model, which can be acquired easily and accurately from sonar or the stacked profile. By using the predicted water-layer multiples, the distinct migration artefacts can be imaged and then subtracted from the migration image of multiples. Numerical experiments illustrate that the proposed approach can suppress most distinct artefacts in the migration of multiples while preserving the advantages. The proposed approach is an effective tool for the removal of artefacts from the migration of multiples and can be applied to different types of migration operators to produce better-illuminated images with fewer artefacts.