| 复杂介质有限元法2.5维可控源音频大地电磁法数值模拟 |
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| 引用本文： | 底青云,Martyn Unsworth,王妙月.复杂介质有限元法2.5维可控源音频大地电磁法数值模拟[J].地球物理学报,2004,47(4):723-730. |
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| 作者姓名： | 底青云 Martyn Unsworth 王妙月 |
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| 作者单位： | 中国科学院地质与地球物理研究所,北京,100029;Department of Physics,University of Alberta,Edmonton Albert Canada,T6G 2J1 |
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| 基金项目： | 中国科学院知识创新工程重要方向资助项目 (KZCX3 SW 13 4) |
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| 摘 要： | 利用有限元2.5维可控源音频大地电磁法（简称CSAMT）数值模拟方法，对100Ωm均匀半空间介质中有限长度的电偶极源产生的电场、磁场及视电阻率、相位特征进行了数值模拟，研究了场的空间变化规律. 在一个象限中，场的特征存在双叶现象，当收发距大于4个趋肤深度时，电阻率较接近介质真实的电阻率，这些结果为观测系统和收发距的选择提供了依据. 波数域场的特征表明，低波数对源的贡献占较大的比例. 有限元法2.5维CSAMT数值模拟的优势在于能较准确地获得复杂介质结构的波场特征. 本文结合直立异常体、倾斜异常体及断陷模型对CSAMT电阻率、相位剖面特征及频率曲线特征的可靠性进行了研究. 数值模拟结果直观地给出了异常体的剖面异常形态. 通过对比研究异常体的剖面异常形态和半空间场的特征进一步说明本文方法和软件在模拟复杂介质结构场特征时是可靠的. 这为认识观测数据，指导反演解释提供了较好的依据.
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| 关 键 词： | 复杂介质 2.5D 可控源音频大地电磁法 有限元法 数值模拟 |
| 文章编号： | 0001-5733(2004)04-0723-08 |
| 收稿时间： | 2003-5-12 |
| 修稿时间： | 2004-2-24 |
2.5-D CSAMT MODELING WITH THE FINITE ELEMENT METHOD OVER 2-D COMPLEX EARTH MEDIA |
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| DI Qing-Yun Martyn Unsworth WANG Miao-Yue Institute of Geology and Geophysics,Chinese Academy of sciences,Beijing ,China.2.5-D CSAMT MODELING WITH THE FINITE ELEMENT METHOD OVER 2-D COMPLEX EARTH MEDIA[J].Chinese Journal of Geophysics,2004,47(4):723-730. |
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| Authors: | DI Qing-Yun Martyn Unsworth WANG Miao-Yue Institute of Geology and Geophysics Chinese Academy of sciences Beijing China |
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| Institution: | 1.Institute of Geology and Geophysics, Chinese Academy of sciences, Beijing 100029, China 2 Department of physics, University of Alberta, Edmonton Alberta, T6G 2J1, Canada |
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| Abstract: | This paper discusses deeply the characteristics of EM field for 2 D complex earth media. We introduce the characteristics of electric field, magnetic filed and apparent resistivity, and phase produced by a finite electrical dipole source over 100Ωm homogeneous half space media. From this result we know the field change behavior over the distance from the transmitter to the receiver, and that we should use a proper transmitting receiving mode. In wave number domain, the EM field shows that the field of low wave number contributes much more than that of high wave number. And then we demonstrate the CSAMT forward modeling apparent resistivity, phase pseudosetions and frequency curves for two anomaly bodies, two lean anomaly bodies and down faulted anomaly. Numerical modeling results show directly the anomaly characteristics. This is very helpful for recognizing field data and data inversion and interpretation. |
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| Keywords: | Complex earth media 2 5-D CSAMT Finite element method Numerical modeling |
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