裂缝及介质非均匀散射

Scattering due to inhomogeneity of media

1. 清华大学, 北京100084;2. 中国地质大学, 北京100083

Tsinghua University, Beijing 100084

为配合地球物理衍射CT的研究, 本文对几何非均匀(尤指裂缝)引起的散射及介质非均匀(尤指弹性系数摄动)所产生的散射场, 运用弹性动力学得到了解析式与数值结果。裂纹散射场可用裂纹张开位移COD与Green应力张量的褶积表示。其远场特性的研究在油气勘探中对预测裂隙位置、方向及大小均有重要意义。

To play a supporting role in the research on geophysical diffraction tomography we have analytically formulated the scattered field caused by inhomogeneity either in geometry of media(esp the cracks) or in property of media (e. g. the purturbation of clastic parameters) based on the principle of elastodynamics and a set of numerical solutions is thus obtained. The scattered field caused by a crack can be expressed in terms of the convolution of crack opening displacement (COD) with Green stress tensor. The study on its far field fcatures is of significance to the prediction for the position, orientation, and size of a crack.