Facies-Constrained Well Log Interpolation for Initial Velocity Modeling of Full Waveform Inversion

In seismic exploration, establishing a reliable velocity model is crucial for seismic migration imaging and reservoir description. Full Waveform Inversion (FWI) aims to recover subsurface physical parameters by minimizing the misfit between the observed and synthetic data, theoretically offering the highest modeling accuracy. However, FWI’s success relies on a good initial model due to its nonlinearity. We propose a Face-Constrained Kriging (FC-Kriging) method based on well log interpolation to establish a better initial model for FWI. We firstly use the initial model to perform reverse time migration (RTM) to extract stratigraphic structure. Based on the stratigraphic information, we further obtain seismic facies classification results. The facies model provides useful lateral structural information in the FC-Kriging method, which enables effective interpolation results even with a limited number of wells data. Compared with conventional Kriging, the FC-Kriging method produces clearer boundaries and higher resolution, which contributes to a more accurate initial model for FWI. In addition, the FC-Kriging method can mitigate the local “bull’s eye” anomalies in conventional Kriging method. The residual anomalies in the FC-Kriging results can also be further eliminated through subsequent FWI. We have applied this methodology to the synthetic model, and the results proved the correctness and effectiveness.