Compensation for transmission losses based on one-way propagators in the mixed domain
Compensation for transmission losses based on one-way propagators in the mixed domain
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DOI：
10.1190/geo2011-0460.1
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发表时间：
2012-03
期刊：
影响因子：
3.3
通讯作者：
Weijia Sun;L. Fu
中科院分区：
文献类型：
--
作者：
Weijia Sun;L. Fu
基于单程波动方程的真振幅偏移算法大多涉及几何展布校正和地震Q衰减校正。然而，很少有文章讨论的传输损耗（CTL）的补偿基于单程波方程。在这里，我们提出了一种方法来补偿传输损耗使用单向波传播的二维情况下。该格式是从Lippmann-Schwinger积分方程导出的。CTL方案由传输项和相移项组成。透射项补偿了波在地下传播时的振幅。透射项是两个相邻异质屏的垂直波数的函数。相移项是通过傅里叶变换在混合域中实现的傅里叶有限差分（FFD）传播算子。传输项可以灵活地并入到常规相移偏移算法中，即，FFD，每个深度步长。分析了频率、横向速度差和垂向速度比对公式精度的影响。从一个平面模型和故障模型的横向速度变化的数值例子来证明所提出的计划的传输损耗补偿的能力。
Most true-amplitude migration algorithms based on oneway wave equations involve corrections of geometric spreading and seismic Q attenuation. However, few papers discuss the compensation of transmission losses (CTL) based on one-way wave equations. Here, we present a method to compensate for transmission losses using one-way wave propagators for a 2D case. The scheme is derived from the Lippmann-Schwinger integral equation. The CTL scheme is composed of a transmission term and a phase-shift term. The transmission term compensates amplitudes while the wave propagates through subsurfaces. The transmission term is a function of the vertical wavenumbers of two adjacent heterogeneous screens. The phase-shift term is a Fourier finite-difference (FFD) propagator implemented in a mixed domain via Fourier transform. The transmission term can be flexibly incorporated into the conventional phaseshift migration algorithm, i.e., FFD, at every depth step. We analyze the effects of frequency, lateral velocity contrast, and vertical velocity ratio on the accuracy of the presented formulae. Numerical examples from a flat model and a fault model with lateral velocity variations are presented to demonstrate the ability of the proposed scheme for compensation of transmission losses.