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本文介绍一种地震偏移新方法,通过将其与线性地震反演和广义 Radon 变换结合起来,可使经典的绕射(或共切线)叠加公式化。本方法是按等时面上的积分将偏移作为重建地层声波散射势进行再计算的。本方法理论上是以几何光学 Green 函数解波动方程以及利用广义 Radon变换的近似反演公式为依据的。文中介绍的方法既能控制复杂的速度模型,也能控制(几乎)任意的震源和接收器排列。在一般情况下,本方法可用来作为一种加权绕射叠加。加权值可通过追索由成像点至实验震源和接收器的射线进行确定。如果本算法用来验证斜井的 VSP 有限差分模拟(这是用常规波动方程法很难解决的一种混合型实验),则本算法可精确重建断层地层模(?)文中解析重建公式是在背景速度为常数的零偏移距和固定偏移距地(?)况下按一般公式推导获得的。零偏移距反演公式类似于标准的 Kirchhoff 偏移。文章分析向我们提供了实验体系(震源和接受器位置、震源子波、背景速度)和重新的空间分辨率之间的直接关系。合成实例说明,地震成像横向分辨率用本理论即可得到明确说明,如果结合地面资料和钻孔资料还能获得进一步改进。最佳的分辨率可根据被成像区域周围的零偏移距实验来获得。
In this paper, a new method of seismic migration is introduced. By combining it with linear seismic inversion and generalized Radon transform, classical diffraction (or co-tangent) stacking can be formulated. This method recalculates the offset by using the integral on isochronism as the reconstruction of the acoustic scattering potential of the formation. This method is theoretically based on the solution of the wave equation of Geometrical Optical Green’s function and the approximate inversion formula of generalized Radon transform. The approach presented in this article controls both the complex velocity model and the (almost) arbitrary source and receiver arrangement. In general, the method can be used as a weighted diffraction superposition. Weights can be determined by tracing the ray from the imaging point to the experimental source and receiver. If this algorithm is used to verify the VSP finite difference simulation of a deviated well, which is a hybrid experiment that is difficult to solve with the conventional wave equation method, the proposed method can accurately reconstruct the fault formation model Background speed is a constant of zero offset and fixed offset (?) Derived according to the general formula. The zero-offset inversion formula is similar to the standard Kirchhoff offset. The article analysis provides us with a direct relationship between the experimental system (source and receiver positions, source wavelet, background velocity) and re-spatial resolution. The synthetic example shows that the lateral resolution of seismic imaging can be clearly described by this theory. If the ground data and drilling data are combined, further improvements can be obtained. The best resolution can be obtained by experimenting with zero offset around the area being imaged.