弹性波波场正演模拟的研究

The study of elastic wave field for ward modeling

本文讨论弹性波波场二维正演模拟问题。首先由动量平衡定律导出用应力分量表示的二维弹性波波动方程,然后用傅里叶变换法求解其波场。在求解过程中,采用了强行吸收边界,在不扩大模型、不增加计算量和存储量的情况下,较好地解决了傅里叶变换数值解法中产生的折叠效应和边界反射问题,并实现了自由表面的模拟。模型试验表明,根据波在不同介质中的传播规律,使我们有可能利用波场图像来区分异常区的岩性和含油气特性。

2D elastic wave field forward modeling is discussed. 2D elastic wave equation expressed in stress components is derived using momentum conservation law, then the wave field is calculated using Fourier transform. The use of forced absorption boundary not only greatly attenuates boundary reflection and aliasing which occur in Fourier transform but also achieves free-surface modeling, without the model,calculation and internal storage enlarged. Model experiments show that it is possible for us to identify lithology and hydrocarbon conditions in abnormal area in terms of wave field characters and images in different media.