Long-offset-aided Full-waveform Inversion

When using FWI, the common scheme was to use data sets which have relatively large offsets up to 8 km or more and frequencies as low as 2.8 Hz considering surface seismic acquisition. In terms of the marine environment, Wide Azimuth towed streamer (WAZ) or Ocean Bottom Cable (OBC) data collection provide the above mentioned specifications. Recent advances in acquiring data such as the dual coil system offer significant improvements in characteristics over WAZ and OBC such as better illumination, noise attenuation, lower frequencies, and longer offsets which allow the FWI to more accurately determine the velocity field. The data set that we input to FWI is a result of dual-coil acquisition where the maximum offset is up to 14000 m with full azimuth distribution. Our results demonstrate that FWI can be used for velocity update with the long offsets and low frequencies provided by the dual coil seismic acquisition. In particular, the shallow section of the model can be significantly enhanced by using FWI which can result in an improved overall depth image. Finally, we show the reverse time migration depth image improvements by using the FWI developed velocity field versus that one from the ray-based methodology.