基于包络目标函数的弹性波波形反演

弹性波场的复杂性致使反演问题非线性性增强,寻优过程极易陷入局部极值。多尺度反演能在一定程度上提高反演的稳定性及分辨率,但多尺度反演策略无法解决实际数据的低频缺失问题。针对该问题,提出了一种新的基于包络目标函数的弹性波多尺度反演策略。首先将包络反演方法应用到弹性波,恢复地下弹性介质参数中的低波数信息；然后将包络反演结果作为常规多尺度反演的输入,进一步提高反演的稳定性。Marmousi2模型试算结果表明该策略能够更加准确地反演纵、横波速度以及密度信息。

The complexity of elastic wavefield will increase the nonlinearity of inversion and make the inverse problem fall into local minima.Multi-scale inversion algorithms can improve the stability and resolution of inversion to a certain extent,but it cannot solve the problem of low frequency missing in real data.To alleviate this problem,we propose a new multi-scale scheme based on envelope inversion to obtain the elastic parameters accurately.The main procedures are as follows:Firstly,we extend the envelope inversion method to elastic medium to estimate the low wavenumber components of elastic parameters; then,the envelope inversion results are used as the initial model of conventional multi-scale inversion to further improve the stability of the inversion.The Marmousi2 model test results show that the new multi-scale scheme can estimate P- and S- wave velocities more accurately,as well as the density information.

国家自然科学基金(41174100和41074087)和中国石化地球物理重点实验室开放基金联合资助。