Rapid expansion and pseudo spectral implementation for reverse time migration in VTI media
Rapid expansion and pseudo spectral implementation for reverse time migration in VTI media
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DOI：
10.1088/1742-2132/9/3/291
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发表时间：
2012-06
影响因子：
1.4
通讯作者：
R. Pestana;B. Ursin;P. Stoffa
中科院分区：
文献类型：
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作者：
R. Pestana;B. Ursin;P. Stoffa
在各向同性介质中，利用标量声波方程对压力波场资料进行逆时偏移。在各向异性介质中，P波和SV波相互耦合，RTM应采用弹性波动方程。为了计算效率，通常使用伪声波方程。这可以使用二阶偏微分方程的耦合系统来求解。我们解决这些问题，使用伪谱方法和快速扩展方法（REM）的显式时间推进。该方法除了产生感兴趣的P波到达之外，还产生退化SV波。为了避免这个问题，垂直横观各向同性（VTI）介质的弹性波动方程可以分为单独的波动方程的P-和SV-波。这些分离的波动方程是稳定的，并且它们可以有效地用于VTI介质中的地震数据建模和偏移，其中|ϵ − δ|很小。SV波的伪影也已删除。独立的伪微分波方程可以解决一个为每个模式使用伪谱方法的空间导数和REM的显式时间推进的波场。我们展示了数值稳定和高分辨率的建模和RTM结果的纯P波模式在VTI介质。
In isotropic media, we use the scalar acoustic wave equation to perform reverse time migration (RTM) of the recorded pressure wavefield data. In anisotropic media, P- and SV-waves are coupled, and the elastic wave equation should be used for RTM. For computational efficiency, a pseudo-acoustic wave equation is often used. This may be solved using a coupled system of second-order partial differential equations. We solve these using a pseudo spectral method and the rapid expansion method (REM) for the explicit time marching. This method generates a degenerate SV-wave in addition to the P-wave arrivals of interest. To avoid this problem, the elastic wave equation for vertical transversely isotropic (VTI) media can be split into separate wave equations for P- and SV-waves. These separate wave equations are stable, and they can be effectively used to model and migrate seismic data in VTI media where |ϵ − δ| is small. The artifact for the SV-wave has also been removed. The independent pseudo-differential wave equations can be solved one for each mode using the pseudo spectral method for the spatial derivatives and the REM for the explicit time advance of the wavefield. We show numerically stable and high-resolution modeling and RTM results for the pure P-wave mode in VTI media.