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高斯射线束完全可以理解为频率域的实体,即将平面波方向特性与一个有效的有限的支撑作用范围结合起来所具有的某些性质的实体。那些明显的特性不仅留存于所讨论的观察平面里而且也存在于整个射线传播路径中。本文提出了一种旨在将原始地震资料转换成射线束叠加资料的预处理技术。这就是人工合成时域谐和函数的高斯射线束,以取代通常所用的倾斜叠加法生成的平面波。本文所提出的方案以一个待定自由参数(实质上就是射线束宽度)为特征值,该参数的选择对于最终的成功是至关重要的。本文还给出了这些参数选择的专门准则。在射线束的宽度为零和无限大的范围内,射线束叠加可相应地分别简化成原始野外资料和常规的倾斜叠加资料。虽然射线束叠加基本上是一种频率域的方法,但在不损失有限空间支撑作用下,使用所选择频带内的频率成份,可以实现一种由频率域到时间域的转换。选择射线束迭加资料作为以后进行反演的起点,其优点可以从两个层次来阐述:首先,有限空间支撑作用的内在特性克服了边界效应。其次,由射线束迭加获得的定位质量可以为新的地震成象方法指明途径。
A Gaussian beam is well understood as an entity in the frequency domain, an entity of some nature that combines the directional characteristics of a plane wave with an effective limited range of support. Those obvious features are not only retained in the observation plane in question but also in the entire ray propagation path. In this paper, a pretreatment technique is proposed to convert the original seismic data into ray superposition data. This is the Gaussian beam that synthetic time-domain harmonic functions are synthesized to replace the plane waves generated by the ramp stacking method commonly used. The scheme proposed in this paper is characterized by a pending free parameter (essentially the beam width). The choice of this parameter is crucial to the eventual success. This article also gives specific guidelines for the selection of these parameters. In the range of the beam width of zero and infinity, the beam superposition can be simplified into the original field data and the conventional tilt superposition data respectively. Although beam bundling is essentially a method of frequency domain, it is possible to achieve a frequency-domain to time-domain conversion using the frequency content of the selected frequency band without loss of limited space support. The advantage of choosing the superposition of ray beams as the starting point for inversion in the future can be explained from two levels: First, the inherent properties of finite space support overcome the boundary effect. Second, the quality of the position obtained by the superposition of the beam can indicate the way for a new seismic imaging method.