Study on the full‐waveform inversion strategy for 3D elastic orthorhombic anisotropic media: application to ocean bottom cable data
Study on the full‐waveform inversion strategy for 3D elastic orthorhombic anisotropic media: application to ocean bottom cable data
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三维弹性正交各向异性介质全波形反演策略研究：在海底电缆数据中的应用
DOI：
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发表时间：
2019
影响因子：
2.6
通讯作者：
T. Alkhalifah
中科院分区：
文献类型：
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作者：
Ju;T. Alkhalifah
多参数全波形反演是估计储层地下各向异性特性的重要工具，储层可能具有复杂的地质行为，需要弹性正交介质描述。对于这种弹性正交介质，考虑到描述介质的大量参数，找到适当的反演策略来减轻参数权衡并减少零空间至关重要。我们将最近开发的正交介质反演策略应用于合成和真实海底电缆数据，并找到最有效的反演策略。首先，我们分析了冰球形模型的三个弹性正交参数化的权衡模式。然后，我们在从通道形模型获得的 3D 合成海底电缆数据上比较这些正交参数化的性能。通过解释基于每个参数化中九个弹性正交参数的解析辐射图的反演模型，我们观察到具有一个纵波速度、一个横波速度和七个无量纲参数的参数化可以最佳地在反演的早期阶段恢复地下各向同性。然后，我们表明，三个各向异性参数的选择及其沿水平面的偏差有助于我们通过解耦各向异性特征（分别具有垂直和水平对称轴）来减轻多参数反演的复杂性。这种各向同性和各向异性性质的解耦使我们能够以多阶段的方式进行多参数各向异性反演。此外，对于海洋采集，我们表明参数数量可以从9个减少到4个，这使得多参数反演更加实用。最后，我们将弹性正交反演应用于真实的海底电缆数据。
The multi‐parameter full waveform inversion is an essential tool to estimate subsurface anisotropic properties in a reservoir that may have complex geological behaviour requiring an elastic orthorhombic medium description. For such elastic orthorhombic media, finding a proper inversion strategy to mitigate parameter trade‐off and reduce the Null space is crucial considering the large number of parameters describing the medium. We apply our recently developed strategy for orthorhombic medium inversion on synthetic and real ocean bottom cable data, and find the most efficient inversion strategy. At first, we analyse the trade‐off patterns in three elastic orthorhombic parameterizations for a hockey‐puck‐shaped model. We, then, compare the performance of these orthorhombic parameterizations on a 3D synthetic ocean bottom cable data, which are obtained from a channel‐shaped model. By interpreting the inverted models based on analytic radiation patterns of the nine elastic orthorhombic parameters in each parameterization, we observe that parameterizations, which have one P‐wave velocity, one S‐wave velocity and seven dimensionless parameters, can be optimal to recover subsurface isotropic properties in the early stages of inversion. Then, we show that the choice of three anisotropic parameters and their deviations along the horizontal plane helps us mitigate the complexity of the multi‐parameter inversion by decoupling anisotropic features, which have vertical and horizontal symmetric axes, respectively. This decoupling of isotropic and anisotropic properties enables us to perform the multi‐parameter anisotropic inversion in a multi‐stage manner. In addition, for the marine acquisition, we show that the number of parameters can be reduced from 9 to 4, which makes the multi‐parameter inversion more practical. Finally, we apply the elastic orthorhombic inversion to real ocean bottom cable data.