win德赢

Abstract: The parameter reconstruction of strong-scattering media is a challenge for conventional full waveform inversion (FWI). Direct envelope inversion (DEI) is an effective method for large-scale and strong-scattering structures imaging without the need of low-frequency seismic data. However, the current DEI methods are all based on the acoustic approximation. Whereas, in real cases, seismic records are the combined effects of the subsurface multi-parameters. Therefore, the study of DEI in elastic media is necessary for the accurate inversion of strong-scattering structures, such as salt domes. In this paper, we propose an elastic direct envelope inversion (EDEI) method based on wave mode decomposition. We define the objective function of EDEI using multi-component seismic data and derive its gradient formulation. To reduce the coupling effects of multi-parameters, we introduce the wave mode decomposition method into the gradient calculation of EDEI. The update of Vp is primarily the contributions of decomposed P-waves. Two approaches on Vs gradient calculation are proposed, i.e. using the petrophysical relation and wave mode decomposition method. Finally, we test the proposed method on a layered salt model and the SEG/EAGE salt model. The results show that the proposed EDEI method can reconstruct reliable large-scale Vp and Vs models of strong-scattering salt structures. The successive elastic FWI can obtain high-precision inversion results of the strong-scattering salt model. The proposed method also has a good anti-noise performance in the moderate noise level.