Elastic least-squares reverse time migration
Elastic least-squares reverse time migration
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DOI：
10.1190/geo2016-0254.1
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发表时间：
2016-09
期刊：
影响因子：
3.3
通讯作者：
Zongcai Feng;G. Schuster
中科院分区：
文献类型：
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作者：
Zongcai Feng;G. Schuster
摘要本文利用弹性最小二乘逆时偏移（LSRTM）方法对纵横波阻抗反射率图像进行反演。弹性LSRTM解决了线性化的弹性波方程的正演模拟和伴随方程反向传播的剩余波场在每次迭代。对合成数据和实际资料的数值试验表明，弹性LSRTM方法优于弹性逆时偏移（RTM）和声波LSRTM方法。对于我们的示例，与弹性RTM图像相比，弹性LSRTM图像具有更好的分辨率和幅度平衡、更少的伪影和更少的串扰。与声学LSRTM图像相比，图像也更好地聚焦，并且对于陡倾事件具有更好的反射体连续性。与传统的最小二乘偏移类似，弹性LSRTM也需要精确估计P波和S波偏移速度模型。然而，问题仍然是，当速度模型中存在中等误差和强多次波时，LSRTM ...
ABSTRACTWe use elastic least-squares reverse time migration (LSRTM) to invert for the reflectivity images of P- and S-wave impedances. Elastic LSRTM solves the linearized elastic-wave equations for forward modeling and the adjoint equations for backpropagating the residual wavefield at each iteration. Numerical tests on synthetic data and field data reveal the advantages of elastic LSRTM over elastic reverse time migration (RTM) and acoustic LSRTM. For our examples, the elastic LSRTM images have better resolution and amplitude balancing, fewer artifacts, and less crosstalk compared with the elastic RTM images. The images are also better focused and have better reflector continuity for steeply dipping events compared to the acoustic LSRTM images. Similar to conventional least-squares migration, elastic LSRTM also requires an accurate estimation of the P- and S-wave migration velocity models. However, the problem remains that, when there are moderate errors in the velocity model and strong multiples, LSRTM ...