Numerical simulation of the field source for the CSAMT folded line source in a homogeneous half-space
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摘要: 可控源音频大地电磁法(CSAMT)在野外进行测量时, 通常认为发射线源是简化为长度极小的电偶极子源, 但是在野外实测中, CSAMT发射线源都是折线形布设。本文在前人研究成果的基础上, 根据电磁场的线性叠加原理推导出折线形电流线源激发的电磁场数值计算方法, 通过对不同的折线形线源模型进行计算, 分析均匀半空间情况下折线形线源对视电阻率、阻抗相位曲线的影响。模型计算表明折线形线源对视电阻率、阻抗相位曲线的近区和过渡区有较大影响, 远区则不受影响; 近区和过渡区受到的影响主要是由各个折线段的方位角引起, 折线段方位角越大, 对测点的视电阻率和阻抗相位的影响越大。当折线段方位角很小时, 可以将其忽略并近似为直线源进行处理, 这样既可以充分考虑发射源的形态又可以提高工作效率。为后续CSAMT数据处理的近场校正以及CSAMT数值模拟提供了理论支持。Abstract: For field surveys using the controlled source audio magnetotelluric (CSAMT) method, it is generally believed that the CSAMT line source is a simplified electric dipole source with a minimal length. However, CSAMT line sources are all arranged in a folded line pattern in field surveys. Based on the previous research results, this study derived the numerical calculation method for the electromagnetic field excited by the folded line source according to the linear superposition principle of electromagnetic fields. Through the calculation of different folded line source models, this study analyzed the influences of the folded line source on the apparent resistivity and impedance phase curves in the homogeneous half-space. Model calculations demonstrate that the folded line source significantly influenced the near and transition zones of the apparent resistivity and impedance phase curves but had no influence on their far zones. The influences on the near and transition zones were primarily caused by the azimuths of folded line segments, and higher azimuths were associated with more significant influences on the apparent resistivity and impedance phase of survey points. In the case of very low azimuth angles, the folded line source can be approximated as a straight line source for processing, improving the work efficiency while fully considering the morphology of the emission source. This study provides theoretical support for the near-field correction of subsequent CSAMT data processing and the CSAMT numerical simulation.
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[1] Goldstein M A, Strangway D W.Audio-frequency magnetotellurics with a grounded electric dipole source[J].Geophysics, 1975, 40(4):669-683.
[2] Grandis H, Sumintadireja P.A brief review for the proper application of magnetotelluric (MT) and controlled-source audio-frequency magnetotelluric (CSAMT) in geothermal exploration[C]//12nd annual indonesian geothermal association meeting and conference, 2012.
[3] Di Q Y, Fu C M, An Z G, et al.An application of CSAMT for detecting weak geological structures near the deeply buried long tunnel of the Shijiazhuang-Taiyuan passenger railway line in the Taihang Mountains[J].Engineering Geology, 2020, 268:105517.
[4] Wang G, Lei D, Zhang Z Y, et al.Tensor CSAMT and AMT studies of the xiarihamu Ni-Cu sulfide deposit in Qinghai, China[J].Journal of Applied Geophysics, 2018, 159:795-802.
[5] Streich R.Controlled-source electromagnetic approaches for hydrocarbon exploration and monitoring on land[J].Surveys in Geophysics, 2016, 37(1):47-80.
[6] 底青云, 薛国强, 殷长春, 等.中国人工源电磁探测新方法[J].中国科学:地球科学, 2020, 50(9):1219-1227.
Di Q Y, Xue G Q, Yin C C, et al.New methods of controlled-source electromagnetic detection in China[J].Scientia Sinica:Terrae, 2020, 50(9):1219-1227.
[7] 何继善.可控源音频大地电磁法[M].长沙:中南工业大学出版社, 1990. He J S.Controlled source audio magnetotelluric method[M].Changsha:Central South University of Technology Press, 1990.
[8] 韩元红, 申小龙, 李兵, 等.基于综合物探的关中眉县构造裂隙型地热水靶区预测及钻孔验证[J].物探与化探, 2023, 47(1):65-72.
Han Y H, Shen X L, Li B, et al.Target area prediction and drilling verification of the tectonic fissure-hosted geothermal water in Meixian County, Guanzhong Plain based on the integrated geophysical exploration[J].Geophysical and Geochemical Exploration, 2023, 47(1):65-72.
[9] 王军成, 赵振国, 高士银, 等.综合物探方法在滨海县月亮湾地热资源勘查中的应用[J].物探与化探, 2023, 47(2):321-330.
Wang J C, Zhao Z G, Gao S Y, et al.Application of a comprehensive geophysical exploration methods in the exploration of geothermal resources in Yueliangwan, Binhai County[J].Geophysical and Geochemical Exploration, 2023, 47(2):321-330.
[10] 刘春伟, 王重, 胡彩萍, 等.综合物探方法在胶东岩浆岩缺水山区找水中的应用[J].物探与化探, 2023, 47(2):512-522.
Liu C W, Wang C, Hu C P, et al.Application of a comprehensive geophysical exploration methods to water exploration in magmatic rock mountainous areas with water shortage in Jiaodong Peninsula[J].Geophysical and Geochemical Exploration, 2023, 47(2):512-522.
[11] Wang J L, Lin P R, Wang M, et al.A multiple parameter extraction and electromagnetic coupling correction technique for time domain induced polarisation full waveform data[J].Exploration Geophysics, 2019, 50:113-123.
[12] 陈卫营, 薛国强, 崔江伟.电性源瞬变电磁发射源形变对观测结果影响分析[J].地球物理学进展, 2015, 30(1):126-132.
Chen W Y, Xue G Q, Cui J W.Analysis on the influence from the shape of electric source TEM transmitter[J].Progress in Geophysics, 2015, 30(1):126-132.
[13] 李展辉, 黄清华.任意形状水平接地导线源瞬变电磁法一维正反演研究[J].地球物理学进展, 2018, 33(4):1515-1525.
Li Z H, Huang Q H.1D forward modeling and inversion algorithm for grounded galvanic source TEM sounding with an arbitrary horizontal wire[J].Progress in Geophysics, 2018, 33(4):1515-1525.
[14] 商天新, 张继锋, 冯兵, 等.任意形状水平电性源瞬变电磁全区视电阻率计算[J].地球科学与环境学报, 2020, 42(6):749-758.
Shang T X, Zhang J F, Feng B, et al.Calculation of all-time apparent resistivity for arbitrary horizontal electrical source transient electromagnetic method[J].Journal of Earth Sciences and Environment, 2020, 42(6):749-758.
[15] 王鹏飞, 王书明, 安永宁.不规则回线瞬变电磁法一维烟圈反演研究[J].地球物理学进展, 2019, 34(3):1113-1120.
Wang P F, Wang S M, An Y N.One-dimensional smoke ring inversion of irregular loop source transient electromagnetic method[J].Progress in Geophysics, 2019, 34(3):1113-1120.
[16] 李建平, 李桐林, 张亚东.层状介质任意形状回线源瞬变电磁场正反演[J].物探与化探, 2012, 36(2):256-259.
Li J P, Li T L, Zhang Y D.Tem forward and inversion of arbitrary shape loop source in layered media[J].Geophysical and Geochemical Exploration, 2012, 36(2):256-259.
[17] 李建平, 李桐林, 赵雪峰, 等.层状介质任意形状回线源瞬变电磁全区视电阻率的研究[J].地球物理学进展, 2007, 22(6):1777-1780.
Li J P, Li T L, Zhao X F, et al.Study on the TEM all-time apparent resistivity of arbitrary shape loop source over the layered medium[J].Progress in Geophysics, 2007, 22(6):1777-1780.
[18] 李建平, 李桐林, 张辉, 等.不规则回线源层状介质瞬变电磁场正反演研究及应用[J].吉林大学学报:地球科学版, 2005, 35(6):790-795.
Li J P, Li T L, Zhang H, et al.Study and application of the TEM forward and inversion problem of irregular loop source over the layered medium[J].Journal of Jiling University:Earth Science Edition, 2005, 35(6):790-795.
[19] 刘云鹤, 殷长春, 翁爱华, 等.海洋可控源电磁法发射源姿态影响研究[J].地球物理学报, 2012, 55(8):2757-2768.
Liu Y H, Yin C C, Weng A H, et al.Attitude effect for marine CSEM system[J].Chinese Journal of Geophysics, 2012, 55(8):2757-2768.
[20] 王若, 王妙月, 卢元林.高山峡谷区CSAMT观测系统研究[J].地球物理学进展, 2004, 19(1):125-130.
Wang R, Wang M Y, Lu Y L.CSAMT observation system study in high mountain and steep gorge area[J].Progress In Geophysics, 2004, 19(1):125-130.
[21] 王艳波.考虑发射源起伏的CSAMT一维正演研究[J].物探化探计算技术, 2016, 38(1):30-36.
Wang Y B.1D forward modeling of CSAMT on rolling source[J].Computing Techniques for Geophysical and Geochemical Exploration, 2016, 38(1):30-36.
[22] 周子琨, 翁爱华.不规则发射源对可控源电磁测深的影响规律[C]//2018年中国地球科学联合学术年会论文集(二十二)--专题45:海洋地球物理、专题46:电磁地球物理学研究应用及其新进展.北京, 2018:66-67.
[23] 张斌, 谭捍东.带地形的可控源音频大地电磁法二维正演[J].物探与化探, 2014, 38(1):151-156.
Zhang B, Tan H D.The two-dimensional csamt modeling with topography[J].Geophysical and Geochemical Exploration, 2014, 38(1):151-156.
[24] Xiong Z T, Tang X G, Li D D, et al.Linear source CSAMT response simulation in the 2D anisotropic formation with topography[J].Journal of Applied Geophysics, 2019, 171:103861.
[25] 陈小斌, 赵国泽.关于人工源极低频电磁波发射源的讨论--均匀空间交流点电流源的解[J].地球物理学报, 2009, 52(8):2158-2164.
Chen X B, Zhao G Z.Study on the transmitting mechanism of CSELF waves:Response of the alternating current point source in the uniform space[J].Chinese Journal of Geophysics, 2009, 52(8):2158-2164.
[26] 刘地渊, 徐凯军, 赵广茂, 等.任意形状线电流源三维地电场研究[J].地球物理学进展, 2006, 21(2):395-399.
Liu D Y, Xu K J, Zhao G M, et al.The study of three-dimensional geo-electric field of arbitrary shape line sources[J].Progress in Geophysics, 2006, 21(2):395-399.
[27] 苏巍, 李大俊, 翁爱华.均匀半空间有限长接地导线源地面电场响应特征[J].地质与勘探, 2019, 55(3):801-808.
Su W, Li D J, Weng A H.Characteristics of the electric field generated by a finite-length-ground wire source in homogeneous half-space[J].Geology and Exploration, 2019, 55(3):801-808.
[28] Nabighian M.Electromagnetic methods in applied geophysics[M].Tulsa:Society of Exploration Geophysicists, 1988.
[29] 徐士良.计算机常用算法[M].北京:清华大学出版社, 1995. Xu S L.Common computer algorithms[M].Beijing:Tsinghua University Press, 1995.
[30] 刘云, 宋滔, 王赟.大定源回线瞬变电磁场数值滤波算法[J].物探化探计算技术, 2016, 38(4):437-442.
Liu Y, Song T, Wang Y.A digital filter method for evaluating the fixed-loop transient electromagnetic field[J].Computing Techniques for Geophysical and Geochemical Exploration, 2016, 38(4):437-442.
[31] 何光渝, 高永利.Visual Fortran常用数值算法集[M].北京:科学出版社, 2002. He G Y, Gao Y L.Visual Fortran commonly used numerical algorithm set[M].Beijing:Science Press, 2002.
[32] Wang X X, Deng J Z.A comparative study on the difference between the multi-dipole sources and vector synthesis source[J].Journal of Environmental and Engineering Geophysics, 2020, 25(4):529-543.
[33] 王显祥, 底青云, 许诚.CSAMT的多偶极子源特征与张量测量[J].地球物理学报, 2014, 57(2):651-661.
Wang X X, Di Q Y, Xu C.Characteristics of multiple sources and tensor measurement in CSAMT[J].Chinese Journal of Geophysics, 2014, 57(2):651-661.
[34] Kaufman A A, Keller G V.Frequency and transient soundings[M].Amsterdam:Elsevier Scientific Pub.Co., 1983.
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