摘要
薄层探测问题一直是地球物理勘探关注的重点,以往的研究大多关注的是不同地球物理方法对薄层的探测效果,却没有关注观测参数对探测结果的影响。拟选用电性源瞬变电磁法,以一维正演理论为基础,通过定义相对异常表征分辨能力,研究偏移距、观测时间与分辨能力之间的关系,从而决定如何选择合适的观测参数以实现薄层异常的快速有效勘探。结果表明:瞬变电磁法对薄层的分辨能力随着偏移距的增大先呈线性递减后逐步趋于稳定,同时所需的观测时间也逐渐增大;分辨能力的衰减速率随着电阻率及埋藏深度的增大逐渐减弱。综上所述,采用较小的偏移距进行数据采集,不仅有利于提高勘探精度,也能相应地提升勘探效率。
The detection of thin layers has always been paid a lot of attention in geophysical prospecting,but previous researches mainly focus on the detection results of different geophysical methods while ignoring the influence of the observation parameters.The grounded-wire transient electromagnetic method(TEM)was chosen to the thin layer detection,and the relationship between offset,observation time and detection capability was analyzed based on the 1D forward modeling and the defined relative anomaly,which was used to reflect the detection capability of the TEM for thin layers.Hence,the way on how to choose proper observation parameters for fast and fine detection of thin layers was given.The results show that detection capability of transient electromagnetic method for thin layers becomes decreased linearly and then gradually tends to be stable with the increase of the offset,at the same time,the demanded observation time becomes longer,which is bad for actual field measurement.Besides,the decrease speed of detection capability becomes slower with the increasing of resistivity or buried depth.Therefore,it is concluded that adopting short offset in data collecting not only can improve the detection accuracy,but also can improve the detection efficiency.
作者
雷康信
薛国强
陈卫营
周楠楠
LEI Kang-xin;XUE Guo-qiang;CHEN Wei-ying;ZHOU Nan-nan(Key Laboratory of Mineral Resources,Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,China;College of Earth and Planetary Sciences,University of Chinese Academy of Sciences,Beijing 100049,China;Innovation Academy of Earth Science,Chinese Academy of Sciences,Beijing 100029,China;Integrated Geophysical Simulation Lab(Key Laboratory of Chinese Geophysical Society),Chang an University,Xi an 710054,Shaanxi,China)
出处
《地球科学与环境学报》
CAS
北大核心
2020年第6期731-736,共6页
Journal of Earth Sciences and Environment
基金
中国科学院科研仪器设备研制项目(YJKYYQ20190004)
自然资源部煤炭资源勘查与综合利用重点实验室开放项目(KF2020-3)
国家自然科学基金项目(41704076)。
关键词
瞬变电磁法
电性源
薄层探测
正演模拟
分辨能力
最大相对异常
偏移距
观测时间
transient electromagnetic method
grounded-wire source
thin layer detection
forward modeling
detection capability
the biggest relative anomaly
offset
observation time
