Automated Salt-Model Building Using Constrained FWI
L. Guasch, T. Lin, F. Herrmann and M. Warner
Event name: 80th EAGE Conference and Exhibition 2018
Session: FWI II - Cycle Skipping And Constrained FWI
Publication date: 11 June 2018
Info: Extended abstract, PDF ( 464.3Kb )
Price: € 20
We apply full-waveform inversion to the full-scale 3D SEAM sub-salt dataset to recover the velocity model starting from a poor approximation to the true model. We use adaptive waveform inversion to provide robustness against cycle skipping, and constrain the model using both total variation and asymmetric hinge-loss total variation applied vertically. These constraints are gradually relaxed as the inversion proceeds. We are able to recover the salt model accurately to a depth of about 5000 m, including the rugose top of salt, salt welds and inclusions, salt flanks and over-hangs, and a slightly lower-velocity carapace lying immediately above the salt; we successfully recover migrated interfaces below base salt to depths of around 10,000m. The inversion uses frequencies between 2 and 7 Hz, includes surface multiples and ghosts in the input data, and does not commit inversion crime.