Multi-scale full waveform inversion based on double diagonal flux correction transport

The continuous furthering of oil and gas exploration exposes seismic exploration to increasingly complex issues. Full waveform inversion (FWI) has become a highly promising velocity modeling method due to its high accuracy. Nevertheless, its inversion effect is largely affected by the accuracy of the initial model and the frequency range of the shot record. In actual seismic data processing, the accuracy of the initial velocity model is often not high, despite that an accurate initial velocity model is the key to preventing FWI from falling into local extreme values. Therefore, reducing the dependence of FWI on the initial model is vital. For this reason, a multi-scale FWI method based on double-diagonal flux correction is proposed in this paper. Specifically, the two-dimensional time-domain acoustic wave equation is corrected by the flux-corrected transport technology to obtain the corrected wavefields of different frequency components. On this basis, the calculation formulas for FWI gradient and step size are derived, and multi-scale inversion is carried out with the corrected wavefields from low frequency to high frequency. Simulation tests with a modified Marmousi model are conducted to verify the effectiveness of the proposed method. The results show that the proposed method effectively expands the medium- and low-frequency components of the wavefield and reduces the dependence of FWI on the initial model. © 2022, Editorial Department OIL GEOPHYSICAL PROSPECTING. All right reserved.