基于波动理论消除表层多次波

Surface-related multiple suppressions based on wave theory

基于波动理论和Berkhout的反馈模型,可通过反馈回路的物理系统产生包括多次波的地震记录,并可表示为一组第二类积分方程。首先通过原始记录与一次波的初始估计值(可以是炮记录本身)的空间褶积预测多次波,再用最小能量准则反演求得的表层算子的逆来标定多次波,最后从原始记录中将多次波消除。整个预测过程无须知道宏观速度场,增强了预测方法的适应性。为更好地消除表层多次波,应采用迭代反演的方法。理论模型试算和实际资料试处理的结果表明,该方法对表层多次波有较好的压制作用,一般只需2～3次迭代即可。其处理效果要优于拉冬变换法,对100炮左右的常规数据来说,一次迭代一般需要30min左右。

Based on the wave theory and Berkhout's feedback model, the seismic record containing multiples could be generated by the physical system with the feedback-loop and also be expressed by a set of secondly integral equation. The multiples will be predicted with the spatial convolution between the original record and the initially estimated value of primary reflection or the seismic record itself. The multiples were scaled using the inverse of the surface operator obtained from the inversion by using the least-squares criterion. Then the primary record could be gained by subtracting the scaled multiples from the original data. This method has a large scale of adaptability, because of unknown macro velocity field. The surface-related multiples could be removed more effectively with the iterative inversion method. The calculated and applied results show that this method generally requires two to three times of iteration and has a good result in suppressing surface-related multiples.