4D full-waveform inversion at the Ivar Aasen field: Results, value proposition and remaining challenges

Four ocean-bottom seismic (OBS) surveys have been acquired at the Ivar Aasen field for time-lapse monitoring. As part of the processing of the last monitor survey, 4D full waveform inversion (FWI) was tested and compared with conventional 4D processing products. Results show that 4D FWI can detect all the expected production effects in a similar way to conventional products. The main potential advantage noted in 4D FWI is that business-critical information can be accessed in a single volume attribute whereas conventional 4D products tend to require extensive analysis of angle stacks and time shifts volumes. Receiver decimation tests indicate that coarser, lower-cost receiver layouts are feasible without compromising monitoring objectives, potentially opening new business opportunities for time-lapse monitoring.