Full Waveform Inversion on the NW Shelf of Australia

A workflow for integrating full waveform inversion (FWI) with reflection tomography has been refined using narrow azimuth towed streamer (NATS) 3D seismic data from the North West Shelf (NWS) of Australia. We show that FWI using relatively short offset NATS data with limited low frequency content can provide a high resolution velocity field if it is combined with reflection tomography in the workflow. Although other techniques exist for building an initial FWI model, reflection tomography was chosen here since a reasonably mature model was accessible from a project being run in parallel. Integration of reflection tomography and associated quality control (QC) practices into the time domain FWI model building sequence was found to be necessary to help the FWI converge to a satisfactory solution when turning ray energy was limited or non-existent. Investigation of typical FWI parameters was also necessary to refine each frequency update. We also show comparisons of inversions for acoustic and elastic impendace from using FWI and reflection tomography data from this area.