地球物理学进展 ›› 2019, Vol. 34 ›› Issue (6): 2328-2335.doi: 10.6038/pg2019DD0211

• 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

陆地可控源电磁法三维勘探的激电效应影响研究

万伟1, 唐新功2, 3, 黄清华1, *   

  1. 1. 北京大学地球与空间科学学院地球物理学系,北京 100871;
    2. “油气资源与勘探技术”教育部重点实验室(长江大学),武汉 430100;
    3. 长江大学非常规油气湖北省协同创新中心,武汉 430100;
  • 收稿日期:2019-05-30 修回日期:2019-08-12 出版日期:2019-12-20 发布日期:2019-12-29
  • 通讯作者: 黄清华,男,教授,1990年毕业于中国科学技术大学,1999年获日本大阪大学博士学位,主要从事地球电磁学、地震物理学方面的教学与科研工作.(E-mail: huangq@pku.edu.cn)
  • 作者简介:万伟,男,1989年生,博士研究生,研究方向为可控源电磁法正反演及应用研究.(E-mail: wanei_py@pku.edu.cn)
  • 基金资助:
    国家自然科学基金(41574104,41674107)资助.

Influence of induced polarization effects on 3D land CSEM sounding

WAN Wei1, TANG Xin-gong2, 3, HUANG Qing-hua1, *   

  1. 1. Department of Geophysics,School of Earth and Space Sciences,Peking University,Beijing 100871,China;
    2. Key Laboratory of Exploration Technologies for Oil and Gas Resources of MOE,Yangtze University,Wuhan 430100,China;
    3. Hubei Cooperative Innovation Center of Unconventional Oil and Gas,Yangtze University, Wuhan 430100,China
  • Received:2019-05-30 Revised:2019-08-12 Online:2019-12-20 Published:2019-12-29

摘要: 可控源电磁法(CSEM)的正演模拟与反演解释中常忽略激电介质的影响.本文基于电磁三维正反演开源平台ModEM,分别开展了陆地CSEM三维正反演以及考虑激电介质的陆地CSEM三维正演研究,并与一维模型解析解对比验证了三维计算的准确性.数值模拟结果显示,模型含激电效应与不含激电效应的电场Ex频率响应差异明显,激电效应会导致电场Ex幅值减小、相位增加,且对Ex的影响程度与激电异常体的频谱特性及观测的收发距均相关.合成数据的陆地CSEM反演结果显示,数据中含激电效应会使得反演出的异常体在深度、规模和电阻率值上都与真实异常体存在较大偏差,忽略观测数据中的激电效应会明显影响观测的准确性.本文研究表明当陆地CSEM三维观测资料中包含激电效应时,有必要考虑其影响.

关键词: 可控源电磁法(CSEM), 激电效应, 频率响应, 三维正反演

Abstract: Induced Polarization(IP) effects are often ignored in the Controlled-Source Electromagnetic(CSEM) data inversion and interpretation. To study the influence of IP effects on 3D land CSEM sounding, we have developed 3D land CSEM forward modeling and inversion based on the open source EM modular inversion platform ModEM. The 3D land CSEM forward modeling with IP effects is also developed. The accuracy of the 3D forward modeling is verified by comparing the 3D numerical results with the 1D analytical solution. The numerical modeling results indicates that IP effects can decrease the amplitude and increase the phase of the electric field Ex. Such influence depends on the IP spectral characteristics of the abnormal body and the distance of between transmitter and receiver. The inversion results of the synthetic CSEM data with and without IP effects show that the IP effects can cause clear deviation in the inversion results, such as the depth, scale and resistivity of anomalous. This study indicates that it is necessary to consider the IP effects in 3D land CSEM exploration.

Key words: Controlled-Source Electromagnetic(CSEM), IP effects, Frequency response, 3D forward and inversion

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