改进的波场外推海底多次波压制方法

海洋地震数据中的海底多次波可以由波场外推的方法得到,然后将之从原始数据中减去,即可达到衰减多次波的目的。该方法除了海水深度参数以外几乎不需要任何先验信息,并且具有良好的保幅特性,因而得到广泛应用;然而,在实际应用中,该方法在压制微屈多次波和鸣震方面仍然不尽如人意。提出了一种改进的波动方程多次波衰减方法,即不考虑水底反射系数问题,而是利用时空变的最小二乘匹配滤波的方法压制多次波,并在理论和实际数据中得到验证。

IMPROVRD WAVE FIELD EXTRAPOLATION TECHNIQUES FOR MULTIPLE WAVE ATTENUATION

In marine geophysical survey, the attenuation of multiple waves is a critical task. Multiple reflections related to water bottom in marine seismic data can be predicted by a combination of numerical wave field extrapolation through the water layer and the estimation of the water bottom multiples. The attenuation of the multiples could be made by subtraction of the predicted wave field from the original record. The proposed method requires almost no any precondition and has a perfect function of amplitude protection. However, there may encounter some drawbacks. For examples, it may behave poorly in the presence of pegleg multiples especially the source side pegleg; and it is weak in overcoming ringing noise. All of these problems can be mitigated by modification of algorithms. In this paper the success of the proposed algorithms has been demonstrated on both numerical experiments and field data processing.