Full Waveform Inversion Using Perfectly Reflectionless Subgridding

摘要

Method for reconstructing subsurface profiles for seismic velocity or other geophysical properties from recorded seismic data. In one embodiment, a starting model of seismic velocity is assumed (10). The computational domain is divided into two (or more) subdomains by horizontal planes based on an analysis of velocity model (30), and the allowed maximum grid size for each subdomain is determined (50). Auxiliary perfectly matched layers (PML's) are attached to each planar interface between subdomains (80), e.g. two PML's on each side of the interface between the coarse and fine subdomains. Simulated seismic data are computed using the SG-DO technique (100-230). The simulated seismic data are compared to the recorded seismic data, then the residual is calculated (240) and used to update the model (320). The method may be iterated until the model is suitably converged (260).

主权项

1. A computer-implemented method for inferring a subsurface model of velocity or other physical property from seismic data obtained from a seismic survey, comprising:
specifying a computational grid for the data inversion, said grid being divided into two subdomains characterized by one subdomain, a coarse grid subdomain, having larger grid cells than the other subdomain, a fine grid subdomain, wherein the two subdomains are separated by an interface called the C-F interface; modifying the computational grid by introducing at least one extra layer into the computational grid on each side of the C-F interface designed such that seismic wave impedances at the C-F interface are matched; using the modified computational grid and an initial subsurface model of velocity or other physical property to perform, on a computer, numerical inversion of the seismic data to update the initial subsurface model.