Controlled Direction Reception Filtering of P- and S-Waves In τ-P Space
Controlled Direction Reception Filtering of P- and S-Waves In τ-P Space
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DOI：
10.1111/j.1365-246x.1990.tb02482.x
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发表时间：
1990-02
影响因子：
2.8
通讯作者：
S. Greenhalgh;I. M. Mason;E. Lucas;D. R. Pant;R. Eames
中科院分区：
文献类型：
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作者：
S. Greenhalgh;I. M. Mason;E. Lucas;D. R. Pant;R. Eames
本文提出了一种改进的偏振位置相关算子，可用于分离多分量地震剖面中的P波和S波。该方法(求S波消光)的实质是利用沿阵列测得的纵波速度剖面，在将地震剖面投影到τ-p空间时，形成信号向量与慢度向量之间的点积。点积(实际上)是一个线性受控方向接收滤波器(CDR类型1)，它选择性地只通过P个到达。第二步是利用逆旋转算子，在正演变换过程中，同时计算P波ω-p‘PASS平面’和正交P波‘消光平面’。为了在原始时间段中保留落在任何ω-p像素内的总能量的测量，需要这两者一起使用。消光平面本身给出了CDRI过滤器在分离通过平面上的像素中的P波能量方面所取得的成功的衡量标准。这种成功的最佳衡量标准是在逐个像素的基础上执行两个ω-p平面的交叉谱矩阵分析(在窗口dω×dp上求和)。本征值的比值产生了偏振的整流性。基于整流性的2-D增益函数可以用作非线性增强函数，以便在逆Radon变换之前增强ω-p通道平面中的强极化P波像素。用合成地震和物理模型地震资料说明了该方法在实现波场分离和背景降噪方面的成功。
SUMMARY This paper presents a modified form of polarization position correlation (PPC) operator which can be used to separate P- and S-waves in a multicomponent seismic profile. the essence of the method (in seeking S-wave extinction) is to form a dot product between the signal vector and the slowness vector during projection of the seismic section into τ-p space, using the P-wave velocity profile measured along the array. the dot product (in effect) is a linear controlled direction reception filter (CDR type 1) which selectively passes only P arrivals. The second step is to use the converse rotation operator, during the forward transform, to compute both the P-wave ω-p‘pass plane’ and the orthogonal P-wave ‘extinction plane’. the two together are needed in order to preserve a measure of the total energy falling within any ω-p pixel in the original time sections. the extinction plane on its own gives a measure of the success achieved by the CDRI filter in isolating P-wave energy in a pixel on the pass plane. the best measure of this success is given by performing a cross-spectral matrix analysis of the two ω-p planes on a pixel-by-pixel basis (summing over a window dω×dp). the ratio of the eigenvalues yields the rectilinearity of polarization. A 2-D gain function based on rectilinearity may be used as a non-linear boost function in order to enhance strongly polarized P-wave pixels in the ω-p pass plane, prior to inverse RADON transformation. The success of this method in achieving wavefield separation and background noise reduction is illustrated with synthetic and physical model seismic data.