Imaging Ocean-Bottom Seismic Data with Acoustic Kirchhoff Pre-Stack Depth Migration: A Numerical Investigation of Migration Responses and Crosstalk Artifacts

Ocean-bottom seismic (OBS) surveys have been applied in marine oil and gas exploration. In the typical OBS observation geometry, the source and receiver are located on/near different datums, i.e., the sea surface and the seafloor. Besides the desired primary reflections, abundant water-layer-related multiples (WLRMs) are the dominant noises. The demultiple processing for OBS data is a long-standing challenging task. If these WLRMs are not properly suppressed, they will be projected into the subsurface domain by the pre-stack depth migration (PSDM) engine, forming crosstalk imaging artifacts. By combining a finite-difference-based wave simulator and an acoustic Kirchhoff PSDM engine, we propose to build up a numerical analysis workflow to address the influence of WLRMs on depth images. We make a classification of typical WLRMs. Through an integrated numerical investigation, we conduct a detailed analysis of basic migration responses, wave-mode crosstalk, and effective artifact suppression solutions. With a generalized mirror migration approach, we emphasize the potential application of turning WLRMs into effective signals. The built-up investigation method and the obtained understanding of multiples can further benefit in suppressing and utilizing multiples in OBS datasets.