Least-squares Gaussian beam migration in elastic media
Least-squares Gaussian beam migration in elastic media
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DOI：
10.1190/geo2018-0391.1
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发表时间：
2019-07
期刊：
影响因子：
3.3
通讯作者：
Y. Yue;P. Sava;Z. Qian;Jidong Yang;Z. Zou
中科院分区：
文献类型：
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作者：
Y. Yue;P. Sava;Z. Qian;Jidong Yang;Z. Zou
高斯波束偏移（GBM）是一种有效的成像方法，它具有成像多个到达的能力，同时保留射线为基础的方法的优点。我们已经将这种方法推广到各向同性介质中弹性波的线性化最小二乘成像。利用波束偏移过程中的偏振信息，将多分量数据动态转换为不同波模式的主分量，然后利用高斯波束作为波场传播算子，构造正演和伴随偏移算子。基于构造的算子，我们制定了一个最小二乘偏移方案，使用预条件共轭梯度法迭代求解。与传统的弹性高斯波束偏移方法相比，该方法可以获得更好的地下照明和更高分辨率的串扰衰减多波成像。该方法还使我们能够实现计算成本和成像精度之间的良好平衡，这两者都是迭代最小二乘偏移的重要要求。在两个人工数据集上的数值试验证明了该方法的有效性。
Gaussian beam migration (GBM) is an effective imaging method that has the ability to image multiple arrivals while preserving the advantages of ray-based methods. We have extended this method to linearized least-squares imaging for elastic waves in isotropic media. We have dynamically transformed the multicomponent data to the principal components of different wave modes using the polarization information available in the beam migration process, and then we use Gaussian beams as wavefield propagator to construct the forward modeling and adjoint migration operators. Based on the constructed operators, we formulate a least-squares migration scheme that is iteratively solved using a preconditioned conjugate gradient method. With this method, we can obtain crosstalk-attenuated multiwave images with better subsurface illumination and higher resolution than those of the conventional elastic Gaussian beam migration. This method also allows us to achieve a good balance between computational cost and imaging accuracy, which are both important requirements for iterative least-squares migrations. Numerical tests on two synthetic data sets demonstrate the validity and effectiveness of our proposed method.