瞬变电磁法观测频率选择的讨论  

Discussed about Selected Observed Frequency of Transient Electromagnetic Method

作　　者：周波帆[1] 李文尧[1] 李粤华[2] 

机构地区：[1]昆明理工大学国土资源工程学院,昆明650093 [2]新南威尔士大学

出　　处：《科学技术与工程》2013年第30期8869-8872,共4页Science Technology and Engineering

基　　金：中国地质调查项目(1212011121273;1212011121266)资助

摘　　要：选择瞬变电磁观测频率时,一般认为探测深部地质体采用低频,探测浅部地质体采用高频。对于高阻围岩中的导电球体,在AD转换部件位数为16位、24位,放大倍数为100倍、1 000倍的条件下,选择野外常见的参数,假设电导率1 S/m,球体半径20 m,埋深为0 m,100 m,300 m和500 m,圆形发送回线半径100 m计算,发现低频无法观测埋深较深的高阻围岩中导电球体的瞬变电磁二次电位响应;而高频可较好地观测浅、中、深部地质体。说明探测深部地质体采用低频这一结论并不是严格成立的。讨论还为实际工作和仪器设计提出了有益的建议。It is widely believed that should use low frequency to detect deep geological body and use high frequency to detect shallow geological body when Choosing observation frequency of transient electromagnetic.To conducting sphere in the surrounding rock of high resistance,if conversion parts number of AD is 16,24,magnification is 100 times,1 000 times,conductivity 1 s/m,sphere radius 20 m,buried depth 0 m,100 m,300 m and 500 m,the circular radius 100 m,low frequency cant observe the secondary potential transient electromagnetic response of conducting sphere in the surrounding rock of high resistance,and high frequency can well observe shallow,middle and deep geologic body.It means the usual conclusion is not strictly true.The discussion also gives actual work and equipment useful suggestions.

关 键 词：瞬变电磁法 二次电位响应 观测频率 仪器精度 有效观测时间 

分 类 号：P631.325[天文地球—地质矿产勘探]