二维三分量TTI 介质Lebedev 网格正演模拟

The two-dimension three-component Lebedev grid simulation in TTImedia

摘要:

鉴于三维各向异性介质(TTI、单斜等)正演模拟在计算量与内存上的巨大消耗以及标准交错网格机制波场插值带来的数值频散，本文采用二维三分量Lebedev 交错网格有限差分方法对TTI 介质进行波场模拟，利用二维介质便可得到3 个相互垂直分量的弹性波场，并利用余弦相似度将其与完全三维正演波场进行对比，分析了该方法的模拟精度。对比测试结果表明，本文方法避免了插值误差，能够精确反映地震波在二维观测平面内的运动学特征，并且平面内质点的偏振速度、振幅能量与三维结果具有较高的相似度，而模拟占用的计算机资源却只相当于三维模拟中的一个二维剖面，是一种高效、准确的各向异性介质数值模拟方法。

Abstract:

In view of the huge consumption on computation and memory of 3D numerical simulation for anisotropic media with TTI or monoclinic symmetry，and the errors caused by wavefields interpolation of standard staggered grid scheme，this paper adopts the two-dimension threecomponent Lebedev scheme finite-difference algorithm with higher precision and efficiency which can get three components wave-fields with just 2D information of the medium． What’s more，we compare the results with that of 3D by means of cosine similarity analysis． The tests show that the three components from our algorithm have high similarity in wave-fields character，energy and the velocity of particle polarization compared with that of 3D，but the computational resources occupied by our method are just one 2D profiles of 3D simulation，and thus proves an efficient， high-accuracy numerical method special for anisotropic media．