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各种实验室和现场的测试都证实包括砂岩、页岩和灰岩的某些岩石表现为地震各向异性。如果不予考虑,各向异性就会在地震资料处理和成像中引起一些问题。典型的问题是同相轴水平位置和深度估算不准确。利用P波数据的物理地震模拟试验已经证实:当用各向同性处理程序对倾斜各向异性层位下面的目标位置进行成像时,成像的位置与真实的位置产生横向上的移动(参见Issac等,1999)。这种横向位移归因于两个方面的影响:速度影响和侧滑影响。前者是由于各向异性的存在,速度在一个方向大于另一个方向;侧滑影响产生于相速度与群速度之间的差异。在这项工作中,对一个物理模型进行了包括P波和S波数据的4个地震模拟试验,目的在于确定S波数据能否对有很强的P波各向异性的倾斜层下面的目标体产生一个更好的图像。试验采用正常的各向同性方法进行处理。
Various laboratory and field tests have confirmed that some rocks, including sandstone, shale and limestone, exhibit seismic anisotropy. If left out of consideration, anisotropy will cause some problems in seismic data processing and imaging. A typical problem is inaccurate estimation of horizontal position and depth of the events. Physical seismic modeling experiments using P-wave data have demonstrated that when an isotropic processing program is used to image the target location below the sloped anisotropy horizon, the imaged position moves laterally from the true location (see Issac et al. , 1999). This lateral displacement is due to two effects: the speed effect and the side slip effect. The former is due to the existence of anisotropy, the velocity in one direction is greater than the other direction; the effect of the side slip arises from the difference between the phase velocity and the group velocity. In this work, four seismic simulations, including P-wave and S-wave data, were performed on a physical model with the objective of determining whether the S-wave data can be valid for targets below the sloped layer with strong P-wave anisotropy The body produces a better image. The test was conducted using the normal isotropic method.