二维弹性波动方程F-K分离

F-K DECOMPOSITION OF 2-D ELASTIC WAVE EQUATION

1. 地质矿产部石油物探研究所;2. 成都地质学院

1. Research Institude of Geophysical Prospecting for Petroleum, Ministry of Geology and Mineral Resources;2. Chengdu College of Earthsciences

本文根据地面弹性波场的运动方程,假定地下弹性介质的密度、拉梅参数及震源特性是用二维函数表示的,求得地面弹性波位移矢量在频率波数域(即F-K域)中的分离矩阵解,并由此建立了地面弹性波位移矢量与波势矢量的矩阵方程,得到弹性波分离矩阵。如果已知野外记录的位移矢量,记录点密度和拉梅参数,测线方向及构造和地层走向,就可分离纵波(P波)、横波(s波)。本文中提出的算法简单、快速、实用能适用于各向同性任意非均匀介质中的弹性波。模型计算和野外资料处理结果表明:此算法能消除纵、横波的干涉,提高分辨率及同相轴的连续性。

According to the elastic wave equation of motion,a decomposable matrix solution could be derived if the medium density,the Lame’s constants and the source signature are all meet the demends as the 2-D function required. In such case,the displacement vector matrix and the potential vector matrix of the earth surface elastic wave can be built up,and the decomposable matrix of the elastic wave could thus be obtained. On condition that the displacement vector, the density of the receiving points,the Lame’s constants,the spread direction as well as the strike of structure and formation are known,the longitudinal wave (P-wave) and the transverse wave (S-wave) could thus be decomposed. The algorithm recommended for wave decomposition is practical and effective,and is easy to carry out and fast in calculation. It is,In practice,suitable for any of the isotropic heterogeneous medium,and has been proved through modelling and field data processing. By using the algorithm, the interference betwwen the P-wave and the S-wave could be eliminated and the resolution as well as the continuity of the event could also be Improved.