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Field Data Application of Sequential Full-Waveform Inversion of Refracted and Rayleigh Waves
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 79th EAGE Conference and Exhibition 2017, Jun 2017, Volume 2017, p.1 - 5
Abstract
This study presents advances in elastic multi-parameter full-waveform inversion (FWI) for near-surface seismic applications. Rayleigh waves and compressional waves are often used in shallow seismic investigations. While Rayleigh waves are highly sensitive to the S-wave structure of the subsurface, refracted P-waves on the other hand provide information about the P-wave velocity structure. A simultaneous application of FWI to both wave types is often difficult in shallow seismic investigations due to the high amplitudes of Rayleigh waves that dominate the calculation of the FWI objective function (misfit). We therefore suggest a new sequential FWI strategy in which we initially invert using the low-amplitude refracted P-waves and then subsequently the full wavefield including Rayleigh waves. We show applications of this sequential FWI strategy to field data and compare the results with conventional multi-parameter FWI, in which both wave types are inverted simultaneously. The new sequential approach exhibits both a better convergence and lower misfit. The resulting S-wave velocity model appears to have a higher spatial resolution, and the P-wave velocity model is better correlated to the S-wave velocity structure.