FULL WAVEFIELD INVERSION USING TIME VARYING FILTERS

摘要

An improved method for reducing the accuracy requirements on the initiation model when performing multi-scale inversion of the elastic wave data (65) by the local objective function optimization (64) is disclosed. Different scales of inverse are caused by incorporating a low-pass filter into the objective function (61) and then reducing the amount of high-frequency data filtered from one scale to the next. In addition, the filter is designed to be time-varying, wherein the low-pass cutoff frequency of the filter decreases as the travel time of the filtered acoustic-wave data increases (62). The filter can be designed using Pratt's criterion to remove local minimums and to perform averages of time and travel time errors (or other statistical values) only for source and receiver locations, not for travel time (63).