摘要
电性源短偏移瞬变电磁法(SOTEM)具有信号强、对低阻异常体分辨率高、探测深度较大,受地形和地下构造影响较小等特点,因而适合于低阻体及精细构造的探测,同时由于SOTEM工作方法简便,探测工具灵活易于操作,所以非常适合地形复杂、施工艰难的工区。本研究通过对电性源短偏移距瞬变电磁法进行理论分析,对不同地电模型响应之间的相对误差及其随异常电阻率的变化特征进行了分析,探讨了SOTEM的电性异常分辨能力;求解得到了SOTEM探测深度的理论判断公式;研究计算及正演模拟了不同时刻层状地电模型瞬变电磁响应的空间分布特征来对最佳观测区域进行分析,得出近场区观测的优越性;最后,以SOTEM在山西大同某煤矿采空区探测中的应用实例来说明该方法的有效性,根据对比,探测结果与钻井信息很好吻合。
The electrical source short-offset transient electromagnetic method（ SOTEM） has characteristics of strong signal,high resolution,large investigation depth,and less influence by topography and underground structure. It is therefore suitable for the detection of low resistivity body and fine structure. In addition,it is easily arranged and the receiving instrument is light and easy to operate,so it is very suitable for difficult field area with complex terrain. In this paper,the SOTEM method is analyzed theoretically,and the spatial distribution characteristics of the transient electromagnetic response of the layered geoelectric model in different time spans are calculated and simulated. The result shows the superiority of the near field observation. Based on the analysis of the relative error of response between different geoelectric models and the variation characteristics with the abnormal resistivity,the authors investigated the capability of SOTEM for discriminating electrical anomalies. In this paper,the authors have obtained the theoretical judgment formula of SOTEM detection depth,and put forward the commonly used formula of probing depth. At the end of this paper,the application of SOTEM to the detection of the gob in a coal mine in Datong of Shanxi Province is given to illustrate the effectiveness of the method. According to the comparison,the detection results coincide with the drilling information.
出处
《物探与化探》
CAS
CSCD
2017年第2期354-359,共6页
Geophysical and Geochemical Exploration
基金
国家重大科研装备研制项目(ZDYZ2012-1-05)
国家自然科学基金项目(41474095)
中国科学院矿产资源研究重点实验室开放课题
国土资源部煤炭资源勘查与综合利用重点实验室开放课题
关键词
电性源瞬变电磁法
SOTEM
LOTEM
低阻体
分辨率
采空区
electrical source transient electromagnetic survey
SOTEM
LOTEM
low resistivity
resolution
mined-out area
