地球物理学进展 ›› 2019, Vol. 34 ›› Issue (5): 1866-1877.doi: 10.6038/pg2019CC0279

• 应用地球物理学Ⅰ(油气及金属矿产地球物理勘探) • 上一篇    下一篇

黏性逆时偏移成像研究进展

豆辉,徐逸鹤   

  1. 中国地震局地球物理研究所,中国地震局地震观测与地球物理成像重点实验室,北京 100081
  • 收稿日期:2018-12-11 修回日期:2019-06-05 出版日期:2019-10-28 发布日期:2019-10-28
  • 作者简介:豆辉,女,1989年生,中国地震局地球物理研究所博士后,主要从事黏声波数值年模拟和逆时偏移成像研究.(E-mail: douhui_crg@163.com)
  • 基金资助:
    中国地震局地球物理研究所基本科研业务费专项(DQJB18B10)

Progress in the Q-compensated reverse time migration imaging

DOU Hui,XU Yi-he   

  1. Institute of Geophysics,China Earthquake Administration(Seismic Observation and Geophysical Imaging Laboratory), Beijing 100081, China
  • Received:2018-12-11 Revised:2019-06-05 Online:2019-10-28 Published:2019-10-28

摘要:

逆时偏移已成为复杂陡倾角构造成像的标准工具.当地下构造含有强衰减体时会强烈的吸收高频能量,导致地震波的振幅减弱和相位失真,常规的逆时偏移技术难以获得较高的成像分辨率.因此,如何在逆时偏移中进行Q补偿(Q-Compensated Reverse Time Migration,Q-RTM),包括幅值补偿和相位矫正,是有效地提高含强衰减特征的复杂地质构造的成像分辨率,并使反射界面在正确位置成像的热门研究方向.但是,在Q-RTM的波场延拓中同时补偿幅值和矫正相位并不那么容易实现,而且在地震波能量补偿过程中放大的高频噪声会引起稳定性问题,这些都是Q-RTM当前需要解决的主要问题.因此,本文首先回顾了Q-RTM近年来的发展现状,介绍了Q-RTM的基本原理和成像条件,分析了当前存在的主要问题及其解决方法,并展望了Q-RTM的未来发展方向.

关键词: Q补偿逆时偏移, 黏声波波动方程, 衰减补偿, 稳定性问题

Abstract:

Reverse Time Migration (RTM) has become a standard tool for complex steep dip imaging. However, the strong attenuated anomalies among the medium will absorb the seismic energy, especially the high frequency content. When using the traditional RTM technique to image the strong attenuated structures, it is difficult to derive high precision images of the internal and lower structures of the media. To overcome these attenuation effects, Q-compensation in Reverse Time Migration(Q-RTM), including amplitude compensation and phase correction, can effectively improve the image resolution of the complex geological structures with strong attenuation characteristics, and locate the reflection interfaces imaging in the correct position. Q-RTM is showing the brilliant ability to improve the resolution of the viscosity medium imaging today. Even though, it’s not easy to implement attenuation compensation in a visco acoustic or elastic wave equation to compensate the amplitude and correct the phase both. Furthermore, the high frequency noise amplification during the seismic energy compensation causes the numerical stability problems, making the work more difficult and complicated.
Firstly, it is not easy to obtain a proper wave equation for the Q compensation. Nowadays, there are mainly two types of Q models, the constant Q model and the nearly constant Q model, to describe the viscous medium simulation. Based on different models to describe the Q behavior, the two categories of wave equations show the same simulation results. Besides, the constant Q wave equation exhibits most convenient in Q compensating as the equation can be separated into two parts: the amplitude attenuation and phase distortion. The nearly constant Q wave equation, based on the generalized Maxwell or standard linear solid, is able to simulate a more complex Q structure, and easily to be implemented in the parallel environment with higher effective calculation. Secondly, there are also many other problems to solve in the procedure of the Q-RTM, like the stability problems and computation cost. The stability problems, caused by the amplification of amplitude in the reverse wave propagation and calculation errors, will make serious influence on calculation and prevent obtaining desired quality images. There are many approaches have been proposed to solve the stability problems. For example, low-pass filter, regularization, new image conditions and least square Q-RTM. They are valid to mitigate the stability problems in improving the image quality, and deriving high resolution images.
Considering these above questions, we will detail review the progress of the Q-RTM, the theory of it and problems exist, approaches to solve the problems, and future trend of Q-RTM in the paper.

Key words: Q-compensated reverse time migration, Visco-acoustic wave equation, Attenuation compensation, Stability problem

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