波动方程偏移速度建模:一种直接反演方法  

Wave equation based migration velocity estimation: a direct inversion approach

作　　者：张江杰[1,2] 张剑锋[1] 

机构地区：[1]中国科学院地质与地球物理研究所,北京100029 [2]中国科学院研究生院,北京100049

出　　处：《地球物理学报》2011年第3期835-844,共10页Chinese Journal of Geophysics

基　　金：国家自然科学基金重点项目(40930422);国家科技重大专项(2008ZX05008-006;2008ZX05023-005-010;2008ZX05025 001 005)资助

摘　　要：基于炮域波动方程叠前深度偏移所产出的角道集,发展了不需要多次迭代的波动方程偏移速度建模方法.文中分析了炮域波动方程偏移生成角道集的方法,给出了非均匀介质中角道集同相轴曲率与速度误差的定量关系,发展了基于同相轴曲率的速度模型直接更新算法.在初始模型较合理的情况下,应用一次炮域波动方程偏移计算,即可得到较准确的速度模型.这一方法可用于解决由走时层析成像等方法得到的速度模型与波动偏移方法不匹配的问题,避免了直接由波动方程偏移进行速度建模所需要的多次偏移计算.数值结果证明了本文方法的有效性.We present a non-iterative velocity estimation scheme using the angle gathers resulting from the shot-profile wave equation based pre-stack depth migration. The paper discusses how to generate the angle gathers using shot-profile wave equation based migrations. A quantitative relationship between the curvature of the events in the angle gathers and the velocity perturbations in heterogeneous media is presented. As a result, we propose a direct scheme of velocity model updating based on the curvature of the events in the angle gathers. In the case that a reasonable velocity model is available, we can get a more accurate velocity model with a time shot-profile wave equation migration. This approach can overcome the problem that the velocity model obtained using the travel time tomography does not match the wave equation migration algorithm. Also, the resulting scheme avoids multiple computations of wave equation migrations, as in the current migration velocity estimation. Numerical examples demonstrate the effectiveness of the scheme.

关 键 词：波动方程偏移 速度建模 角道集 直接反演 

分 类 号：P631[天文地球—地质矿产勘探]