A gradient optimization method for the elastic reflection waveform inversion of towed streamer data

ABSTRACT In elastic media, full-waveform inversion requires an accurate initial P-wave velocity model and a good S-wave velocity model to mitigate the nonlinearity of the inverse problem. Elastic reflection waveform inversion (ERWI) recovers the low-wavenumber components of P- and S-wave velocities using migration-demigration techniques. We develop a gradient optimization method for ERWI (GO-ERWI) that reconstructs the P- and S-wave velocity backgrounds using only the pressure component in towed streamer data. The gradient optimization method optimizes the S-wave velocity gradient and reduces crosstalk between parameters. Numerical and field data experiments demonstrate the effectiveness of GO-ERWI.