地球物理学进展 ›› 2019, Vol. 34 ›› Issue (1): 406-411.doi: 10.6038/pg2019CC0172

• 应用地球物理学Ⅱ(海洋、工程、环境、仪器等) • 上一篇    下一篇

电极布置方式对高密度电法探测分辨率的影响

杨磊1,2,金维浚1,2,尚彦军1,2   

  1. 1. 中国科学院地质与地球物理研究所,北京 100029
    2. 中国科学院地球科学研究院,北京 100029
  • 收稿日期:2018-04-26 修回日期:2018-09-05 出版日期:2019-02-20 发布日期:2019-04-15
  • 作者简介:杨磊,男,1992年生,硕士研究生,研究方向固体地球物理.(E-mail: 806170894@qq.com)
  • 基金资助:
    国家自然科学基金资助.(41772320)

Effects on the resolution of high-density electrical method by electrodes array deploying

YANG Lei1,2,JIN Wei-jun1,2,SHANG Yan-jun1,2   

  1. 1. Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China
    2. Academy of Earth Science, Chinese Academy of Sciences, Beijing 100029, China
  • Received:2018-04-26 Revised:2018-09-05 Online:2019-02-20 Published:2019-04-15

摘要:

高密度电法据观测到的视电阻率数据及其反演后的电阻率剖面来推断地下地质结构.传统高密度电法受限于测线长度和电极装置,存在着一些弊端,如探测深度较浅,在测线端点处分辨率差,并且分辨率随深度增加而下降,特别当存在浅层低阻屏蔽时,电流难以向深部传播,分辨率降低.针对上述问题,为提高高密度电法探测的分辨率,本文介绍了一种新型高密度电法野外布极方式:多电极埋入技术(Multi-Electrode Resistivity Implant Technique,MERIT).通过室内模型测试和野外实地检验,将其与传统高密度电法排列进行比较,结果表明MERIT布极方式在测线端点处和地下深部分辨率有显著提高.在相同测线长度下,探测深度增加,对低阻体的反映更灵敏,受到低阻屏蔽效应减小,能够反映深部更丰富的地层信息.故MERIT能够有效地克服传统高密度电法探测存在的缺陷,有效提高探测的分辨率.

关键词: 高密度电法, 分辨率, 多电极埋入技术(MERIT)

Abstract:

High-density electrical method is used to investigate the underground geological structure based on the observed apparent resistivity data used to make the resistivity image section after inversion. First, due to the array configures and the lengths of survey lines, conventional surveys resolve resistivity to depths considerably shallower than the total array length. Second, the resolution of the traditional high-density electrical surveys is decreasing with investigation depth and it shows poor effectiveness near the ends of survey lines. Particularly, the current hardly penetrate into deep layers in the presence of shallow conductive layer, this exacerbates the resolution problem. In order to handle these problems, this paper mainly introduces a new electrode deploying method which is referred to as Multi-Electrode Resistivity Implant Technique , or MERIT. We compare it with conventional High-density electrical method based on laboratory experiments and field case study to verify how MERIT can effectively improve the resolution of high-density electrical method. The result shows that depth of resolution can be approximately increased over that of a conventional surface array of equal length, decrease in depth of penetration due to shallow clay layers is much less in MERIT arrays compared to conventional surface arrays. Besides, MERIT obtains much better resolution at the ends of survey lines, shows more sensitivity to low-resistivity abnormal body and is less vulnerable to shallow conductive layer. More strata information in the depth is obtained between the surface and buried arrays. As a result, MERIT can overcome the shortcomings of conventional High-density electrical method and obtain much better resolution.

Key words: High-density electrical method, Resolution, Multi-Electrode Resistivity Implant Technique(MERIT)

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