绘制复杂层状介质构造图的一种方法

A WAY OF CONSTRVCTING THE STRUCTURAL MAP FOR COMPLICATED LAYERED MEDIUM

大港油田地质调查指挥部计算站

Computer Station of Geological Examination Headquarter, Dogang Oil Field

层状介质中地震波传播路径与各层介质的速度、界面产状及射线初始方向有关。当各层速度差异较大、界面产状各异时,应用平均速度进行空间归位作图,会严重歪曲构造形态,例如:海水与下伏层的产状及速度差异,碎屑岩与下伏石灰岩层的产状及速度差异等均属此类型。这也就是人们通常所说的速度陷井。为了准确地反映这类复杂层状介质的构造形态,本文介绍一种层状介质的空间归位方法。文中推导了全部计算公式,给出了作图方法,并列举了计算机自动绘制构造图的实例。本方法在一些地区使用,证明效果较好。

The seismic wave path in layered medium is related to the velocity in layers and the occurrence of subsurfaces, it is related to the initial orientation of the rays also. When there is an obvious difference between the velocities and the occurrences differs greatly from each other, the structural form would be badly distorted if the dimensional migration was accomplished by average velocity. This often occurs in marine seismic exploration or when clastic rock is overlaid on limestone. In such cases, the velocities and the occurrences of the overlying and underlying strata are commonly quite different. This is the "pitfall of velocity" as the geophysicists used to describe it. The method recommended here is for the dimensional migration of the layered medium. By dint of it, the structural map in complicated layered medium can, thus, be constructed correctly and accurately.In this paper, the formulae for calculating, are derived the method for mapping and example of auto-constructed the structural map by computer are given. And the method mentioned above has been proved to be good in the areas where it has been put to use.