Frequency Domain Full Waveform Inversion Based on Generalized FD Method

The implementation of an accurate and efficient forward/backward modeling approach plays a very important role in full waveform inversion (FWI), in which the finite difference method (FDM) with rectangular grid is mostly adopted. However, the FDM has the ripple-shaped divergence/scattering problem when dealing with uneven interface. On the contrary, a meshless method called generalized FDM (GFDM) is suitable for the flexibility of simulation region and can be of interest for solving the above problem. Hence, we develop a meshless frequency-domain acoustic modeling method with GFDM to improve the accuracy and eliminate the divergence. Then, we apply the GFDM to inverse problem and propose a meshless FWI method. The proposed method reduces lots of the computations and memory usage of frequency-domain FWI and successfully suppresses the ripple-shaped scattering. Numerical examples demonstrate that our method can efficiently improve numerical accuracy and recover an accurate velocity model, which is helpful for high-precision seismic exploration through the complex Earth.