Abstract:15°finite-difference cascade migration has an overmigration problem in practice. It is shown theoretically and experimentally that overmigration results from the accumulation of difference error, which depends on velocity, frequency, interface dip, spatial sampling interval, time sampling interval, depth step, difference scheme and so on. A feasible difference-error compensation method is described, which introduces compensation coefficient R into the original difference wave equation to remove overmigratlon.The compensation coefficient R is the function of time sampling interval (△t), spatial sampling interval (△x), depth step (△τ), interval velocity (V), frequency (?), dip (φ) and approximate second-difference coefficient (B).The effect of these parameters on R is discussed, and the method for determining R is given.Real data experiments stow that this method not only has the advantages of approximate 15°equation but also brings correct migration to 60° dip interface.
凌云, 郑於莹, 郭向宇. 15°有限差分串联偏移问题讨论和方法改进[J]. 石油地球物理勘探, 1989, 24(6): 645-659.
Ling Yun. The discussion on 15° finite-difference cascade migration and the improvement of this method. OGP, 1989, 24(6): 645-659.