A controlled beam migration for anisotropic media and its application to marine data

As exploration areas move from the land to the sea, research targets get more complicated, and the high-precision imaging method becomes critical for marine oil and gas exploration. Gaussian beam migration (GBM) is a robust imaging method with high computational efficiency and flexibility. A high-precision GBM method, suitable for marine observation systems, has been developed by the authors in this paper, which contains the transformation between common-shot and common-offset domains and the data-driven framework. On one hand, considering the anisotropy of the subsurface media, an anisotropic ray tracing equation is introduced. On the other hand, based on the semblance difference between signal and disturbance in the τ-p domain, we develop the semblance threshold filtering method to eliminate disturbance during GBM procedure, thereby reducing migration noise. Numerical tests on anisotropic sag model, modified SEG/Hess VTI model and marine data suggest that (1) anisotropic parameters can improve the imaging quality significantly for the large offset data, (2) the proposed method can more accurately recover the complex structure, and (3) the new method may improve the signal-to-noise ratio (S/N) of the migration profile to a certain extent.