Acoustic approximations for processing in transversely isotropic media
Acoustic approximations for processing in transversely isotropic media
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DOI：
10.1190/1.1444361
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发表时间：
1998-04
期刊：
影响因子：
3.3
通讯作者：
T. Alkhalifah
中科院分区：
文献类型：
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作者：
T. Alkhalifah
当具有垂直对称轴的横观各向同性（VTI）介质使用零倾角正常时差（NMO）速度[Vnmo（0）]和各向异性参数η而不是Brossen参数来表征时，与时间相关的处理[时差校正、倾角时差（DMO）和时间偏移]变得几乎与垂直P波和S波速度（分别为VP 0和VS 0）无关。即使对于相对较强的各向异性，对VP 0和VS 0的独立性也在地震精度的限制范围内。随着比率VS 0/VP 0减小，对VP 0和VS 0的依赖性甚至进一步减小。事实上，对于VS 0 =0，所有与时间相关的处理都只依赖于Vnmo（0）和η。这种对两个参数的幸运依赖性在这里通过与时间相关的处理方程的Vnmo（0）和η的分析推导来证明。时间偏移频散关系、倾斜同相轴的动校正速度以及通过设置VS 0 =0提取的射线追踪方程（即，通过考虑VTI作为声学）不仅德.
When transversely isotropic (VTI) media with vertical symmetry axes are characterized using the zero‐dip normal moveout (NMO) velocity [Vnmo(0)] and the anisotropy parameter ηinstead of Thomsen’s parameters, time‐related processing [moveout correction, dip moveout (DMO), and time migration] become nearly independent of the vertical P- and S-wave velocities (VP0 and VS0, respectively). The independence on VP0 and VS0 is well within the limits of seismic accuracy, even for relatively strong anisotropy. The dependency on VP0 and VS0 reduces even further as the ratio VS0/VP0 decreases. In fact, for VS0=0, all time‐related processing depends exactly on only Vnmo(0) and η. This fortunate dependence on two parameters is demonstrated here through analytical derivations of time‐related processing equations in terms of Vnmo(0) and η. The time‐migration dispersion relation, the NMO velocity for dipping events, and the ray‐tracing equations extracted by setting VS0=0 (i.e., by considering VTI as acoustic) not only de...