Improved Imaging in Complex Shallow Water Environments via Multi-Parameter FWI Imaging

Processing and imaging workflows commonly utilise a variety of techniques such as deghosting, designature, and demultiple to attenuate “undesired” parts of the recorded wavefield that would not be correctly mapped into the image domain by traditional migration algorithms. These preprocessing stages can be intricate and time-intensive due to the sequential way they need to be tested and applied. This is particularly challenging in shallow water marine environments, where strong and relatively short period multiples can obscure desired targets and are non-trivial to attenuate while preserving primary amplitude. Multi-parameter full-waveform inversion (MP-FWI) imaging offers an alternative approach by concurrently determining subsurface parameters, including velocity and reflectivity, utilising raw field data as input. MP-FWI imaging leverages the full recorded wavefield to generate a higher-resolution image with improved amplitude fidelity due to the superior illumination and least squares nature compared to the traditional approach, typically involving Kirchhoff preSDM. This paper compares results derived from a conventional processing and imaging sequence utilising Kirchhoff preSDM against those obtained through MP-FWI imaging. We demonstrate the improvements that MP-FWI imaging can bring in terms of result quality and project turnaround time in the context of a shallow water marine survey acquired in offshore Sarawak, Malaysia.