Imaging diffraction points using the local image matrices generated in prestack migration
Imaging diffraction points using the local image matrices generated in prestack migration
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DOI：
10.1190/1.3277252
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发表时间：
2010-01
期刊：
影响因子：
3.3
通讯作者：
Xiaosan Zhu;R. Wu
中科院分区：
文献类型：
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作者：
Xiaosan Zhu;R. Wu
局部像阵的能量角分布是局部入射角和局部接收角在地下点的函数，平面反射镜和衍射点的能量角分布不同。前者沿某一倾斜方向呈线性分布，后者在整个矩阵中呈散点分布。因此，局部图像矩阵在局部角度域中的奇异值表示能量沿不同倾角方向的分布。利用相邻图像点奇异值集的自相关系数和互相关系数之差，可以区分这两类目标，得到仅包含衍射点的叠前图像。通过三个综合算例，我们发现该方法可以有效地成像衍射点。衍射点的地震图像可以提供有关地质不连续面的重要信息，衍射点可以作为二次震源，在一次波照射不足的盐下构造成像中具有潜在的应用价值。
Energy-angle distributions in the local image matrix, which is a function of local incident and receiving angles at a subsurface point, are different for a planar reflector and a diffraction point. The former exhibits a linear distribution along a certain dip direction, whereas the latter shows a scattered distribution in the entire matrix. Therefore, the singular values of the local image matrix in the local angle domain indicate the energy distribution along different dip directions. The difference between the auto- and crosscorrelation coefficients of the sets of singular values between adjacent image points can be used to distinguish these two types of targets and obtain prestack images which contain only diffraction points. Using three synthetic examples, we found that the method can effectively image diffraction points. Seismic images of diffraction points may provide important information about geological discontinuities and diffraction points can be taken as secondary sources for potential applications in imaging subsalt structures which are poorly illuminated by primary waves.