Elimination of free-surface multiples using least-squares redatuming, Part I: Ocean-bottom seismic data

Ocean-bottom multi-component seismic observation is widely used in marine geological investigation, petroleum exploration, and disasters (like earthquake and tsunami) monitoring. However, the free-surface effects lead to strong multiples in the seismic data recorded at the ocean bottom, which affect velocity model building and seismic migration using the first-order scattering theory. In this paper, based on the principle of data-driven seismic interferometry, a least-squares redatuming method is proposed to mitigate the influence of free-surface and overburden medium, and the work mechanism is revealed by Hessian operator and point-spread-function. Using the separated up- and down-going wavefield recordings, the virtually observed prestack seismic data at the ocean bottom are obtained by iterative inversion without separation of different-order surface-related multiples. Numerical examples of synthetic data show that the proposed approach can effectively suppress the source-sided free-surface effects, enhance the resolution of desired signal, and thus improve the quality of seismic imaging.

Automated summary

In this study, a least-squares redatuming method based on data-driven seismic interferometry is proposed to mitigate the influence of free-surface effects on ocean-bottom seismic data. By separating the up- and down-going wavefield recordings, the virtually observed prestack seismic data at the ocean bottom are obtained, which enhances the resolution of desired signal and improves the quality of seismic imaging.