3D multi-scale full waveform inversion based on the dynamic plane-wave encoding method

Full waveform inversion (FWI) is a relatively accurate velocity modeling method, but it can easily cause cycle jumps owing to a lack of low-frequency and inaccurate background fields.To overcome cycle skipping problem and rapidly construct 3D background velocity model, a plane-wave multi-scale FWI method was proposed.Plane waves were used for building the background field in a 3D observation system, and a new form of conical wave was constructed.By controlling the ray parameters, a multi-scale cone-wave-coded FWI (CFWI) method was implemented to achieve background velocity model inversion.Through the dynamic conical wave coding strategy, the background velocity field can be established using only a small number of plane waves, thereby greatly reducing the amount of inversion calculation.The dynamic cone wave inversion method was applied to test 3D sag and its thrust velocity model.By implementing a multi-source FWI (MFWI), the velocity model could be accurately inverted even for a poor initial model with no low-frequency seismic data.