Migration velocity analysis of seismic signals

摘要

Disclosed is a method for efficiently and accurately determining subsurface velocities for use in migration of seismic data. The method calls for restricting the number of traces considered. This is achieved by a limited-aperture migration, or by trace restriction to those lying upon that portion of the Kirchhoff summation curve wherein the integrand for Kirchhoff migration is smooth. In the preferred embodiment, only a random sample of traces within this aperture are used in the calculations. Improvements in efficiency on the order of a factor of 1000 can be realized with the preferred embodiment.