有限观测角层析研究

A STUDY ON TOMOGRAPHY WITH LIMITED OBSERVING APERTURES

本文首先对层析方法进行了简要评述,提出当前层析技术中存在的主要问题。其次讨论了射线理论层析中有限观测角问题。传统的方法是用计算机软件模拟层析的物理过程,补充观测不到的数据,们不论采用压缩方法或代数重建方法,都受到严格的约制,我们的试验也证实了这点。最后我们根据层析的基本思想,在射线层析中分别求波慢度参数和空间界面,用Radon均值修改中间界面,对有限观测角合成记录(包括地而观测数据,VSP观测数据、跨井观测数据)进行了试验,获得了很好的效果。

A brief review on Tomography in the first section of the paper leads to the understanding of its main existing problems including the problem of limited observing apertures which results in the dcfficicncy of observed data. Covcntionally, computer softwares is usable for simulating the physical process to make up for the defficicncy in observed data. It has however been shown that whether ART or the squashing method suffers from critical restrictions while applied to image reconstructions, this has been shown in our experiments as well. For this end, we have attempted to first separately define slowness parameters and interfaces following the basic principle of Tomgraphy, then modified the resulting interfaces based on the Radon mean values. Such a process has been tested on synthetic data observed with limited apertures including surface, VSP, as well as cross-well data, and good results have been achieved.