|Table of Contents|

Effect of Topographic Relief Outside the Large Loop Source in Transient Electromagnetic Exploration(PDF)

《地球科学与环境学报》[ISSN:1672-6561/CN:61-1423/P]

Issue:
2022年第02期
Page:
338-351
Research Field:
应用地球物理
Publishing date:

Info

Title:
Effect of Topographic Relief Outside the Large Loop Source in Transient Electromagnetic Exploration
Author(s):
RAO Li-ting1;  WU Xin2;  DANG Bo1;  DANG Rui-rong1;  LI Yong3
(1. School of Electronic Engineering, Xi'an Shiyou University, Xi'an 710065, Shaanxi, China; 2. Key Laboratory of Mineral Resources, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China; 3. Beijing Zhongke Diyuan Technology Co., Ltd., Beijing 100190, China)
Keywords:
transient electromagnetic method;  large loop source;  topography;  three-dimensional forward;  finite element method;  anomaly;  conductivity;  numerical simulation
PACS:
P631
DOI:
10.19814/j.jese.2021.08021
Abstract:
The topographic relief has caused great difficulties for the discovery and exploration of mineral resources in China. The calculation and interpretation of transient electromagnetic(TEM)data are often based on flat terrain. The topography can change the distribution of TEM response, which results in some error in recognition of underground targets. To avoid the complex influence of topographic effect, the transmitting source and observation point are normally laid on the flat terrain as possible, but the topography outside the source still impacts on TEM response. In recent years, most of the studies of topographic effect are based on the response curve or apparent resistivity section, while quantitatively evaluations of the degree by topography in the whole observation period are relatively few. The vector finite element method was adopted to perform the three-dimensional forward TEM problems with topography. The model containing topography of ridge and valley were constructed, and the distance between the topography and source, the conductivity of the earth and the anomaly were taken as variable parameters. The effects of topographic relief were investigated through the comparisons of different models. The results show that the topographic effects on EM response mainly reflect in a certain time period, and the topographic effect becomes weaker, the affected area on EM response moves to a later time period as the distance between the topography and source increases; with the increase of earth conductivity, the main affected area of topography on EM response moves to a later time period, but the degree of impact remains the same basically; the influence of valley topography on EM response is greater than that of ridge topography with the same geometric size; the influence of topography and anomaly on EM response can be separated; if the secondary field generated by anomaly is strong enough, the influence of topographic effect can be ignored. The research conclusions provide theoretical basis for the identification and processing of topographic effect in ground TEM exploration.

References:

[1] 薛国强,闫 述,底青云,等.多道瞬变电磁法(MT-EM)技术分析[J].地球科学与环境学报,2015,37(1):94-100.
XUE Guo-qiang,YAN Shu,DI Qing-yun,et al.Technical Analysis of Multi-transient Electromagnetic Method[J].Journal of Earth Sciences and Environment,2015,37(1):94-100.
[2] RAO L T,GAO J S,WU X,et al.A Simple and Robust Total Variation Based Inversion Scheme for Transient Electromagnetic Data[J].IEEE Access,2020,8:16539-16549.
[3] WU X,XUE G Q,HE Y M,et al.Removal of the Multi-source Noise in Airborne Electromagnetic Data Based on Deep Learning[J].Geophysics,2020,85(6):193-208.
[4] 常江浩,薛国强.电性源短偏移距瞬变电磁场扩散规律三维数值模拟[J].地球科学与环境学报,2020,42(6):711-721.
CHANG Jiang-hao,XUE Guo-qiang.Three-dimensional Numerical Simulation of Diffusion Law of Sho-rt-offset Grounded-wire Transient Electromagnetic Field[J].Journal of Earth Sciences and Environment,2020,42(6):711-721.
[5] 邱卫忠.回线源TEM山地勘探中的地形影响和校正方法[J].煤田地质与勘探,2012,40(5):78-81.
QIU Wei-zhong.Topographic Effects and Correction Methods of Loop Source TEM in Mountainous Exploration[J].Coal Geology and Exploration,2012,40(5):78-81.
[6] 殷长春,张 博,刘云鹤,等.2.5维起伏地表条件下时间域航空电磁正演模拟[J].地球物理学报,2015,58(4):1411-1424.
YIN Chang-chun,ZHANG Bo,LIU Yun-he,et al.2.5-D Forward Modeling of the Time-domain Airborne EM System in Areas with Topographic Relief[J].Chinese Journal of Geophysics,2015,58(4):1411-1424.
[7] 张 博,殷长春,刘云鹤,等.起伏地表频域/时域航空电磁系统三维正演模拟研究[J].地球物理学报,2016,59(4):1506-1520.
ZHANG Bo,YIN Chang-chun,LIU Yun-he,et al.3D Modeling on Topographic Effect for Frequency-/Time-domain Airborne EM Systems[J].Chinese Jour-nal of Geophysics,2016,59(4):1506-1520.
[8] 赵 越,李 貅,王炜鹏,等.三维起伏地形条件下航空瞬变电磁响应特征研究[J].地球物理学报,2017,60(1):383-402.
ZHAO Yue,LI Xiu,WANG Wei-peng,et al.Characteristics of Terrain Effect for 3-D ATEM[J].Chinese Journal of Geophysics,2017,60(1):383-402.
[9] 薛国强,闫 述,陈卫营.电磁测深数据地形影响的快速校正[J].地球物理学报,2016,59(12):4408-4413.
XUE Guo-qiang,YAN Shu,CHEN Wei-ying.A Fast Topographic Correction Method for Electromagnetic Data[J].Chinese Journal of Geophysics,2016,59(12):4408-4413.
[10] 曹凤凤.地空瞬变电磁起伏地形效应的特征研究[D].西安:长安大学,2019.
CAO Feng-feng.Study on Characteristics of Rugged Terrain Effect of Ground-airborne Transient Electromagnetic[D].Xi'an:Chang'an University,2018.
[11] 齐彦福,智庆全,李 貅,等.考虑关断时间的地面瞬变电磁三维带地形反演[J].地球物理学报,2021,64(7):2566-2577.
QI Yan-fu,ZHI Qing-quan,LI Xiu,et al.Three-dimensional Ground TEM Inversion over a Topographic Earth Considering Ramp Time[J].Chinese Journal of Geophysics,2021,64(7):2566-2577.
[12] 霍军鹏.倾斜地形对TEM影响分析及其校正方法[J].陕西煤炭,2021,40(5):108-112.
HUO Jun-peng.Analysis of the Influence of Inclined Terrain on TEM and Its Correction Method[J].Shaanxi Coal,2021,40(5):108-112.
[13] 薛国强,常江浩,雷康信,等.瞬变电磁法三维模拟计算研究进展[J].地球科学与环境学报,2021,43(3):559-567.
XUE Guo-qiang,CHANG Jiang-hao,LEI Kang-xin,et al.Review on Three-dimensional Simulations of Transient Electromagnetic Field[J].Journal of Earth Sciences and Environment,2021,43(3):559-567.
[14] NEWMAN G A,HOHMANN G W,ANDERSON W L.Transient Electromagnetic Response of a Three-dimensional Body in a Layered Earth[J].Geophysics,1986,51(8):1608-1627.
[15] XIONG Z H,TRIPP A C.A Block Iterative Algorithm for 3-D Electromagnetic Modeling Using Integral Equations with Symmetrized Substructures[J].Geophysics,1995,60(1):291-295.
[16] ZHDANOV M S,LEE S K,YOSHIOKA K.Integral Equation Method for 3D Modeling of Electromagnetic Fields in Complex Structures with Inhomogeneous Background Conductivity[J].Geophysics,2006,71(6):333-345.
[17] WANG T,HOHMANN G W.A Finite-difference Time-domain Solution for Three-dimensional Electromagnetic Modeling[J].Geophysics,1993,58(6):797-809.
[18] UM E S,HARRIS J M,ALUMBAUGH D L.3D Ti-me-domain Simulation of Electromagnetic Diffusion Phenomena:A Finite-element Electric-field Approach[J].Geophysics,2010,75(4):115-126.
[19] 孙怀凤,李 貅,李术才,等.考虑关断时间的回线源激发TEM三维时域有限差分正演[J].地球物理学报,2013,56(3):1049-1064.
SUN Huai-feng,LI Xiu,LI Shu-cai,et al.Three-dimensional FDTD Modeling of TEM Excited by a Lo-op Source Considering Ramp Time[J].Chinese Journal of Geophysics,2013,56(3):1049-1064.
[20] LI J H,FARQUHARSON C G,HU X Y.3D Vector Finite-element Electromagnetic Forward Modeling for Large Loop Sources Using a Total-field Algorithm and Unstructured Tetrahedral Grids[J].Geophysics,2017,82(1):1-16.
[21] QI Y Z,EL-KALIOUBY H,REVIL A,et al.Three-dimensional Modeling of Frequency- and Time-domain Electromagnetic Methods with Induced Polarization Effects[J].Computer and Geosciences,2019,124:85-92.
[22] 李 貅,胡伟明,薛国强.多辐射源地空瞬变电磁响应三维数值模拟研究[J].地球物理学报,2021,64(2):716-723.
LI Xiu,HU Wei-ming,XUE Guo-qiang.3D Modeling of Multi-radiation Source Semi-airborne Transient Electromagnetic Response[J].Chinese Journal of Geophysics,2021,64(2):716-723.
[23] 张永超,王光杰,李宏杰,等.基于吸收边界条件的瞬变电磁法三维矢量有限元快速正演[J].地球物理学报,2021,64(3):1106-1118.
ZHANG Yong-chao,WANG Guang-jie,LI Hong-jie,et al.Efficient 3D Vector Finite Element Modeling for TEM Based on Absorbing Boundary Condition[J].Chinese Journal of Geophysics,2021,64(3):1106-1118.
[24] HABER E,ASCHER U M,OLDENBURG D W.Inversion of 3D Electromagnetic Data in Frequency and Time-domain Using an Inexact All-at-once Approach[J].Geophysics,2004,69(5):1216-1228.
[25] 周建美,刘文韬,李 貅,等.双轴各向异性介质中回线源瞬变电磁三维拟态有限体积正演算法[J].地球物理学报,2018,61(1):368-378.
ZHOU Jian-mei,LIU Wen-tao,LI Xiu,et al.Research on the 3D Mimetic Finite Volume Method for Loop-source TEM Response in Biaxial Anisotropic Formation[J].Chinese Journal of Geophysics,2018,61(1):368-378.
[26] HABER E,ASCHER U M,ARULIAH D A,et al.Fast Simulation of 3D Electromagnetic Problems Us-ing Potentials[J].Journal of Computational Physics,2000,163(1):150-171.
[27] 胡祥云,李建慧,彭荣华.时间域电磁法勘探的正演问题研究[M].北京:科学出版社,2019.
HU Xiang-yun,LI Jian-hui,PENG Rong-hua.Resear-ch on Forward Modeling of Time Domain Electromagnetic Method[M].Beijing:Science Press,2019.

Memo

Memo:
-
Last Update: 2022-04-30