基于全区视电阻率的半航空瞬变电磁法对低阻薄层的探测能力探讨  

Study on the detection capability of low resistivity thin layer by semi-aviation transient electromagnetic method based on all-time apparent resistivity

作　　者：易国财 王仕兴 王绪本[1] 周军 张赛民[1] 张振雄 郭明[1] 何可[1] YI GuoCai;WANG ShiXing;WANG XuBen;ZHOU Jun;ZHANG SaiMing;ZHANG ZhenXiong;GUO Ming;HE Ke(Key Lab of Earth Exploration and Information Techniques of Ministry of Education,Chengdu University of Technology,Chengdu 610059,China;School of Resources and Environment,University of Electronic Science and Technology of China,Chengdu 610054,China)

机构地区：[1]成都理工大学地球勘探与信息技术教育部重点实验室,成都610059 [2]电子科技大学资源与环境学院,成都610054

出　　处：《地球物理学进展》2021年第4期1760-1768,共9页Progress in Geophysics

基　　金：国家自然科学基金项目“稳定条件突破CFL限制的显式有限差分法模拟地形模型的三维半航空瞬变电磁响应”(41974158);开放基金项目“滑坡地质调查半航空瞬变电磁勘察实验研究”(SKLGP2020K023)资助。

摘　　要：针对使用感应电动势定义全区视电阻率会出现"二值性"的问题,本文采用与电阻率一一对应的垂直磁场分量结合二分搜索算法计算全区视电阻率,这使得全区视电阻率具有唯一性和可靠性.将全区视电阻率的概念引入到半航空瞬变电磁法中,在此基础上,建立以中间层为低阻薄层的三层地电模型,分别绘制了不同低阻薄层埋深与层厚比、围岩与低阻薄层电阻率比的全区视电阻率异常曲线图,并分析其全区视电阻率异常曲线形态及变化规律,通过计算其相对误差,分析并归纳了半航空瞬变电磁法对低阻薄层的探测能力.结果表明全区视电阻率对地下低阻薄层分辨率较好,能较好反映地电断面信息,这对半航空瞬变电磁法有效探测低阻薄层具有实际的指导意义.To solve the problem of "binarity" in defining all-time apparent resistivity by induction electromotive force, this paper uses the vertical magnetic field component corresponding to all-time apparent resistivity and binary search algorithm to calculate all-time apparent resistivity, which makes all-time apparent resistivity unique and reliable. The concept of all-time apparent resistivity is introduced into semi-aviation transient electromagnetic method, on this basis, set up by a thin layer of low resistance for the middle tier three layers of geoelectric model, draw the different conductive thin layer buried depth and thickness ratio, surrounding rock and the resistivity of low resistivity layer than the all-time apparent resistivity anomaly of the graph, and analyzes its form and change law of apparent resistivity anomaly curve. By calculating its relative error, the detection capability of the semi-aviation transient electromagnetic method to the low resistivity thin layer is analyzed and summarized. The results show that the apparent resistivity has better resolution for the low resistivity thin layer and can better reflect the ground electrical section information, which has practical guiding significance for the effective detection of the low resistivity thin layer by the semi-aviation transient electromagnetic method.

关 键 词：半航空瞬变电磁法 全区视电阻率 垂直磁场分量 低阻薄层 探测能力 

分 类 号：P631[天文地球—地质矿产勘探]