Sub‐salt imaging by full‐waveform inversion: A parameter analysis

Sub-salt regions are still a challenge for oil exploration especially with respect to seismic imaging problems. To improve velocity model building in such complex areas, we propose to apply frequency-domain full-waveform inversion. To investigate the influence of key parameters for this method in the salt context, we carried out an analysis of the problem on a selected portion of the 2004 BP velocity benchmark model. The analysis demonstrated the strong non linearity of this sub-salt inverse problem. It emphasized the importance of recording sufficient offsets to ascertain a good illumination of the target zone and confirmed the necessity of low frequencies acquisitions to ensure the success of full-waveform inversion for this application. Extra care in designing the starting model can help to start the inversion at higher frequencies.