杨春,
芦俊,
中国地质大学(北京)地球物理与信息技术学院, 地质过程与矿产资源国家重点实验室, 北京 100083
基金项目: 国家自然科学基金项目（41425017，41604119，41574126）和国家十三五重大专项"薄层地震波场特征与反演研究"专题（2016ZX05002-005-008）联合资助
详细信息
作者简介: 王赟, 男, 1969年生, 博士, 教授、博士生导师, 1998年毕业于中国科学院地球物理研究所, 现从事地震各向异性理论与多分量地震技术的研究. E-mail: yunwang@mail.iggcas.ac.cn
通讯作者: 芦俊, E-mail: lujun615@163.com
中图分类号: P631收稿日期:2017-07-03
修回日期:2018-01-25
上线日期:2018-03-05
Dilemma faced by elastic wave inversion in thinly layered media
WANG Yun,YANG Chun,
LU Jun,
School of Geophysics and Information Technology, China University of Geosciences, State Key Laboratory of Geological Processes and Mineral Resources(GPMR), Beijing 100083, China
More Information
Corresponding author: LU Jun,E-mail:lujun615@163.com
MSC: P631--> Received Date: 03 July 2017
Revised Date: 25 January 2018
Available Online: 05 March 2018
摘要
摘要:对于薄互层地震传播特征的研究我们已有了充分的认识，这是一种完全不同于现有的基于厚层单阻抗差界面地震反射理论的、具有频率依赖性的调谐反射.因而也使得对具有N层结构的弹性介质薄互层反演时，现有有限带宽的基于空间-频率域采样的地震观测难以规避多解性问题.长波长假设下的薄互层VTI近似似乎可以为我们提供一种待反演弹性参数只有5个的可行性方案，使得我们可以将薄互层背景下任一目标薄层的反演看作VTI厚层介质背景下单薄层的反演.但是，我们首先面临薄互层VTI近似的误差和适用性条件等问题；其次，既使对于单薄层厚度的反演，目前地震领域也未能提供一种通用有效的解决方案，实际地震勘探中薄层厚度的预测依然是一个悬而未决的难题.因此在此基础上再进行单薄层的物性参数、裂缝隙和流体的预测则更叠加了难以预知的多解性.显然单纯P波已难以应对，弹性波的介入成为必然；而且单薄层含裂缝与流体的预测更需要横波分裂和双相介质理论的支撑.可以预见的是，除了纵、横波速度，薄互层反射系数的频率依赖性是我们试图给出相对可靠的、单薄层物性精细刻画必须使用的一种重要地震属性.
关键词: 薄互层/
VTI/
单薄层/
弹性波/
反演
Abstract:It's well known that there is a great difference of reflecting characteristics between an interface and a thin-bed, mainly because of frequency interference. Though lots of researches have been contributed to this field, under the condition that the seismic data is only recorded as limited frequency band and sparse space sampling, the elastic inversion in thinly layered media was faced with 3N parameters unknown and seriously ambiguity. Maybe a feasible policy is that only 5 elastic parameters (including 3 Thomsen parameters) need to be predicted based on the approximation of vertically transverse isotropy, so that we can simplify the inversion of thinly layered media as a thin-bed inversion in the VTI background. However, first we need to re-consider the accuracy of quasi-VTI theory and its applicable conditions; secondly, we have to solve the problems encountered by thin-bed inversion. Unfortunately, the thin-bed thickness is still difficult to be predicted precisely, though many studies had been given to this topic since the last century. And more than that, if the elastic attributes, especially fractures and fluids need to be detected in a thin-bed, the inversion of thin-bed will become a more complex mathematical problem. Obviously, only P-wave can't afford to face this challenge, and PS-wave information should be used jointly. Especially, frequency-dependent reflectance of the thin-bed is another important seismic attribute needed to be utilized sufficiently, so that the thin-bed can be delineated precisely and finely.
Key words:Thinly layered media/
Vertically transverse isotropy/
Thin-bed/
Elastic wave/
Inversion
PDF全文下载地址:
http://www.geophy.cn/data/article/export-pdf?id=dqwlxb_14431
