公开(公告)号：US4870580A

公开(公告)日：1989-09-26

申请号：US856608

申请日：1986-04-25

申请人： Stephen W. Lang ,  Michael L. Oristaglio

发明人： Stephen W. Lang ,  Michael L. Oristaglio

IPC分类号： G01V1/28 ,  G01V1/42

CPC分类号： G01V1/42 ,  G01V1/284 ,  G01V2210/161

摘要： Disclosed is separation of the compressional and shear components of the wavefield measured in 3-component vertical seismic profiling. The separation involves working in the zx plane defined by the borehole axis (z) and the surface seismic source space therefrom along the x-axis, and in successive and overlapping windows each defined by (i) a depth interval centered at the depth level currently being processed and including several depth levels above and below and (ii) a time interval sufficiently long to allow the relevant seismic wavefield to be measured by the geophones. The total wavefield measurements in a window are rotated to give the wavefield along the borehole axis (z) and that perpendicular to it in the zx plane of interest. In one embodiment, the result is forward Fourier transformed in two dimensions, then filtered in wavenumber-frequency space by means of a matrix filter which depends on previously estimated compressional and shear speeds of the region that produced the VSP measurements being filtered, and the result is inverse Fourier transformed to derive the compressional component. Subtracting the compressional component from the total measured wavefield gives the shear component. The corresponding operations performed entirely in the spatial domain give corresponding results. In another embodiment, better suited to thin beds, the wavefield components along the x-axis and the z-axis are forward Fourier transformed only temporally, in one dimension, the result is filtered in the space-frequency domain with a space-variant filter which can be different for each borehole depth, and the result is inverse-transformed back to the space-time domain to derive the compressional component.

摘要翻译： 公开了在三分量垂直地震剖面中测量的波场的压缩和剪切分量的分离。 分离涉及在由x轴定义的钻孔轴线（z）和其表面地震源空间中定义的zx平面中工作，以及在连续和重叠的窗口中，每个窗口由（i）以当前深度水平为中心的深度间隔 被处理并包括上下几个深度级别，以及（ii）足够长的时间间隔，以允许地震检波器测量相关的地震波场。 旋转窗口中的总波场测量结果以沿钻孔轴线（z）提供波场，并且在感兴趣的zx平面垂直于波场。 在一个实施例中，结果是二维前向傅里叶变换，然后通过矩阵滤波器在波数频率空间中进行滤波，矩阵滤波器取决于产生正被滤波的VSP测量的区域的先前估计的压缩和剪切速度，结果 被逆傅立叶变换以导出压缩分量。 从总测量的波场中减去压缩分量给出剪切分量。 完全在空间域中执行的相应操作给出相应的结果。 在另一个实施例中，更适合于薄床，沿着x轴和z轴的波场分量在一个维度上仅在时间上进行前向傅里叶变换，结果在空间 - 频率域中用空间变量滤波器 对于每个钻孔深度可以是不同的，并且将结果逆向变换回到时空域以导出压缩分量。