地震偏移成像不确定性分析初探

An attempt to the analysis of uncertainty in seismic migration imaging

勘探地球物理领域存在大量宏观动力学过程的物理数学表达及尚待深入探索的不确定性事实,其中一类是源自对偶量的不可交换性或不可对易性.本文从地震偏移成像中的不确定性分析入手,探讨偏移成像中受到波场延拓过程不确定性的影响.文中给出了若干深度偏移算法对Marmousi模型的偏移不确定度分布表达及图像显示;文中还对若干波场延拓方法,从不确定性估计的角度进行了比较.笔者认为对应用技术领域中的宏观不确定性分析,将有益于深化对宏观动力学过程的理性认识,也为偏移算法评价提供一种途径;重要的是,进行不确定性分析将有利于把握所用偏移算法的不确定度分布,继而有针对性地采取相应的改善措施,以期提高算法的整体确定性程度.

In exploration geophysics realm, there are abundant mathematical physics expressions for macro-dynamic procedures and many concerning uncertainty facts need to be probed among which there exists a certain uncertainty originating from the non-interchangeability of dual variables. Starting from the uncertainty analysis in seismic migration imaging, the effects due to uncertainty of wavefield extrapolation procedure in migration imaging are analyzed in this paper. The uncertainty distribution expression and its image display for some depth migration algorithms with Marmousi model are presented so as to compare, from the viewpoint of uncertainty evaluation, their performances in imaging. We hold macro uncertainty analysis in applicable technological fields can help us to deepen the rational understanding about macro-dynamic procedure also provide us an evaluation approach for migration algorithm. Moreover, we can benefit from uncertainty analysis to obtain the uncertainty degree distribution of adopted migration algorithm, then accordingly to rectify that algorithm with improving measures so as to increase its global certainty.