Page 17 - 《应用声学》2021年第3期

第 40 卷 第 3 期 Vol. 40, No. 3
2021 年 5 月 Journal of Applied Acoustics May, 2021

⋄ 研究报告 ⋄

井间地震波场数值模拟和弹性波逆时偏移 ∗

李梦真 1,2,3 何 晓 1,2,3† 陈 浩 1,2,3 李 超 1,2,3

(1 中国科学院声学研究所 声场声信息国家重点实验室 北京 100190)
(2 北京市海洋深部钻探测量工程技术研究中心 北京 100190)
(3 中国科学院大学 北京 100049)

摘要：该文利用时域有限差分法数值模拟了井间地震波场，探讨了井间地震弹性波逆时偏移成像的若干问题。
基于多层地层模型，根据数值模拟的人工合成阵列信号，对比了 3 种不同成像条件下井间地震逆时偏移的结
果，并对不同倾角的狭缝模型进行逆时偏移成像。通过对不同成像条件的对比，发现震源归一化成像条件能够
对检波器一端的地质结构成像进行增强。由于纵波和横波在折射过程中的相互转换，利用这种透射转换波和
反射波，对于任意倾角的狭缝都可获得清晰的弹性波逆时偏移结果。特别是对于夹角为 90 的垂直狭缝模型，
◦
如果仅提取反射波只能获得狭缝两端点的成像结果，而保留下纵波和横波在透射狭缝时产生的转换波可应用
于高倾角反射体的偏移成像。
关键词：井间地震；逆时偏移；弹性波；成像条件
中图法分类号: P631.4+25 文献标识码: A 文章编号: 1000-310X(2021)03-0335-08
DOI: 10.11684/j.issn.1000-310X.2021.03.003

Numerical simulation of cross-well seismic wave field and elastic wave
reverse time migration

LI Mengzhen 1,2,3 HE Xiao 1,2,3 CHEN Hao 1,2,3 LI Chao 1,2,3

(1 State Key Laboratory of Acoustics, Institute of Acoustics, Chinese Academy of Sciences, Beijing 100190, China)
(2 Beijing Engineering Researcher Center of Deep-sea Drilling and Exploration Beijing 100190, China)
(3 University of Chinese Academy of Sciences, Beijing 100049, China)

Abstract: In this paper, the cross-well seismic wave fields are simulated by the finite-difference time-domain
method. And some problems in the imaging of cross-well seismic wave reverse time migration are discussed.
Based on the multi-layer formation model and the synthetic array signals, the results of cross-well seismic
reverse time migration under three different imaging conditions are compared. Reverse time migration imaging
is carried out for fracture models with different dip angles. From the comparison between different imaging
conditions, it is found that the source normalized imaging conditions can enhance the geological structure
imaging at one end of the geophone. Due to the mutual conversion of P-wave and S-wave in the process of
refraction, clear reverse time migration results of elastic wave can be obtained for any inclined slit by using
the transmitted converted waves and reflected waves. Especially for the vertical fracture model with an angle
of 90 degrees, if the reflected waves are extracted, only the imaging results of the two ends of the slit can be
obtained, while the converted P and S waves generated during the transmission through the fracture can be
applied to the migration imaging of high dip reflector.
Keywords: Cross-well seismic; Reverse time migration; Elastic wave; Imaging conditions

2020-06-22 收稿; 2020-09-11 定稿
国家自然科学基金项目 (11774373)
∗
作者简介: 李梦真 (1995– ), 女, 山西大同人, 硕士研究生, 研究方向: 井间地震逆时偏移成像的研究。
通信作者 E-mail: hex@mail.ioa.ac.cn
†