起伏地表地震波场角度域照明分析

角度域照明可以更加细致地对地下复杂地质体进行照明分析。提出了一种适用于起伏地表条件下的角度域照明分析方法，其主要过程是利用局部倾斜叠加技术分解波场，对起伏地表处采用加权函数判定局部时窗内的振幅包络位置，以区分其位于地表之上或之下；并引入相似系数函数计算反假频局部平面波场，根据局部斜率与平面波场入射角关系，得到局部角度域地震波场；根据帕斯瓦尔等式下的时间-角度域照明关系式，计算得出角度域照明强度。通过起伏地表高速侵入矿体模型试算，得到给定观测系统下角度域照明强度与地下分析点照明随炮点、波场入射角的变化关系。此方法可用于起伏地表条件的观测系统优化、叠前AVA分析等方面。

Method of Angle-Domain Illumination Analysis on Rugged Surface

Angle domain illumination can be used to analyze underground complex geological body. In this paper, we proposed a method of angle-domain illumination analysis at rugged surface. The main process is using local slant stack technique to decompose seismic wavefield, and judging weighting function for rugged surface to determine the aptitude of the Green function within local time window to distinguishing whether it is above or underneath the surface. Semblance function to calculate local plane wavefield for anti-aliasing is introduced. According to the relationship between local slope of the plane wavefield and angle of incidence, we obtained the local angle domain seismic wavefield. Using the relationship between time-angle domain illumination and Paz Val equation, we calculated the illumination intensity in angle domain. During a test on an ore body under rugged surface, we acquired the angle domain illumination intensity and the relationship between the intensity of the underground point and the position of shot and the incident angles of the wavefield in the given observing systems. This method could be applied to optimizing observing systems on ragged surface and pre-stack AVA analysis.