Full Waveform Inversion for Reflected Seismic Data

Full waveform inversion has been successful in building high resolution velocity models for shallow layers. To achieve this, it requires refracted waves or low frequencies in the reflection/refraction data. To relax the dependence on low frequency reflections, we revisit full waveform inversion. We propose a new approach allowing the updating of long wavelength components of the velocity model affecting the reflected arrivals. Our approach is based on a non-linear iterative relaxation approach where short and long wavelength components of the velocity model are updated alternatively. We study theoretically the associated Frchet derivatives and gradients and discussed how and why such a strategy improves the resolution that we can expect from full waveform inversion. Finally we present a first 2D application to a 2D Gulf of Mexico conventional streamer dataset.