弹性波正演模拟及成像方法研究

发布时间：2018-02-26 03:11

本文关键词： 波动方程有限差分法深度偏移正演模拟　出处：《成都理工大学》2015年硕士论文　论文类型：学位论文

【摘要】：地震数值模拟是地震勘探学和地震学的重要基础,它指的是在假定已知地下介质结构模型和相应物理参数的情况下,模拟研究地震波在地下各种介质的传播规律,并计算在地面或地下各观测点所应观测到的数值地震记录的一种数值模拟方法。本文主要对弹性波动方程正演模拟及偏移成像技术进行研究,这两种技术都是目前油气勘探开发的重要方法。本文首先对波动方程的基础理论进行了研究,从本构方程、几何方程和运动平衡微分方程出发,论证了声波和弹性波传播的各种形式的波动方程。然后,在此基础上,利用有限差分法,对声波方程和弹性波方程进行了正演模拟和波场特征分析。再次,对正演模拟的边界条件、稳定性条件、频散、高阶差分系数等重要问题的做了系统性研究。然后,从二阶标量声波方程入手,利用有限差分法实现了声波方程的数值模拟,对地震波的波场特征有了初步的认识。在此基础上,实现了弹性波方程正演模拟,并与声波方程的波场特征进行了对比分析。同时,对波动方程数值模拟中的边界问题展开研究。对完全匹配层边界条件做了三种衰减因子的对比分析。最后,对偏移成像技术进行了研究。首先介绍了偏移成像技术的发展现状,然后介绍了波动方程偏移中的重要理论——延拓和成像,并论述了两种偏移方法的延拓算子。使用波动方程单程波波动方程,对纵波速度模型正演模拟,其后对纵波正演地震记录,采用所介绍的延拓及成像方法进行叠后及叠前深度偏移,并对其结果进行评价,判断地质体归位效果以及偏移算子的适应性。最后用对纵、横波速度模型进行正演模拟,用弹性波正演地震记录,分别对垂直分量、水平分量进行叠前深度偏移,并对偏移叠加剖面进行分析,得到转换波剖面的一些特征,并提出一些问题和今后的研究方向。
[Abstract]:Seismic numerical simulation is an important foundation of seismic exploration and seismology. It refers to the simulation study of the propagation of seismic waves in various underground media on the assumption of known structural models of underground media and corresponding physical parameters. In this paper, the forward modeling of elastic wave equation and migration imaging technique are studied. These two techniques are important methods for oil and gas exploration and development. In this paper, the basic theory of wave equation is studied, starting from constitutive equation, geometric equation and motion equilibrium differential equation. The wave equations of acoustic wave and elastic wave propagation are proved. Then, by using finite difference method, forward simulation and wave field characteristic analysis of acoustic wave equation and elastic wave equation are carried out. The boundary condition, stability condition, dispersion, high order difference coefficient and other important problems of forward modeling are systematically studied. Then, starting with the second order scalar acoustic wave equation, the finite difference method is used to realize the numerical simulation of acoustic wave equation. Based on the preliminary understanding of the wave field characteristics of seismic wave, the forward modeling of elastic wave equation is realized, and the characteristics of wave field are compared with that of acoustic wave equation. At the same time, The boundary problem in numerical simulation of wave equation is studied. The three attenuation factors of perfectly matched layer boundary conditions are compared and analyzed. Finally, the migration imaging technology is studied. Firstly, the development of migration imaging technology is introduced. Then it introduces the important theory of wave equation migration-continuation and imaging, and discusses the continuation operator of two migration methods. By using wave equation one-pass wave equation, the forward modeling of longitudinal wave velocity model is simulated. After that, the continuation and imaging methods are used to carry out post-stack and pre-stack depth migration for the forward seismic records of P-wave, and the results are evaluated to judge the effect of geological body homing and the adaptability of migration operator. The S-wave velocity model is used for forward modeling and elastic wave forward seismic records are used to carry out prestack depth migration for vertical component and horizontal component respectively. Some characteristics of converted wave profile are obtained by analyzing the migration stack profile. Some problems and future research directions are put forward.
【学位授予单位】：成都理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P631.4

【相似文献】