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用正演VSP模拟形式解的固定项组合导出了VSP波场分离中P波和S波的解析解。对该疗法在合成记录和野外数据中的实际应用实例进行了研究和评价。应用此方法几乎没有波场畸变并能提取被主波列掩盖的弱波场。在频率—深度(f—z)域中分解后的波场可用各道高达三阶差分的线性组合形式表示,它可用实际分离过程中道差近似表示。一般而言,在处理中需要用5道单分量数据,但是,在采用声波时,用了3道数据即可完成相同的处理。在数据集的边缘应用了两道外推,以增加道差的精度。由于算法是在f—z域实现,故可以考虑滞弹性的影响。算法中使用了快速傅氏变换,因此计算速度很快。
An analytic solution of P wave and S wave in VSP wavefield separation is derived from the fixed term combination of forward VSP simulated form solutions. The practical application of the therapy in synthetic records and field data was studied and evaluated. This method has almost no wave field distortion and can extract the weak wave field masked by the main wave train. The wavefield decomposed in the frequency-depth (f-z) domain can be represented by a linear combination of up to third-order differences in each channel, which can be approximated by the channel difference in the actual separation process. In general, five single-component data is required for processing, but the same processing is done with three data when using acoustic waves. Two extrapolations are applied to the edge of the dataset to increase the accuracy of the trace. As the algorithm is implemented in the f-z domain, we can consider the impact of the anelasticity. Fast Fourier transforms are used in the algorithm, so calculations are fast.