Three-dimensional tensor controlled-source electromagnetic modeling based on the vector finite-element method
Hu Ying-Cai1, Li Tong-Lin1, Fan Cui-Song2, Wang Da-Yong3, and Li Jian-Ping4
1. College of Geo-Exploration Science and Technology, Jilin University, Changchun 130026, China.
2. Tianjing Center, China Geological Survey, Tianjing 300170, China.
3. Institute of Geophysical and Geochemical Exploration, Chinese Academy of Geological Sciences, Langfang 065000, China.
4. College of Geosciences and Technology, ShanDong University of Science and Technology, Qingdao 266590, China.
Abstract：
Scalar CSAMT is only suitable for measurements in one and two dimensions perpendicular to geological structures. For complex 3D geoelectric structure, tensor CSAMT is more suitable. In this paper, we discuss 3D tensor CSAMT forward modeling using the vector finite-element method. To verify the feasibility of the algorithm, we calculate the electric field, magnetic field, and tensor impedance of the 3D CSAMT far-zone field in layered media and compare them with theoretical solutions. In addition, a three-dimensional anomaly in half-space is also simulated, and the response characteristics of the impedance tensor and the apparent resistivity and impedance phase are analyzed. The results suggest that the vector finite-element method produces high-precision electromagnetic field and impedance tensor data, satisfies the electric field discontinuity, and does not require divergence correction using the vector finite-element method.
Hu Ying-Cai,Li Tong-Lin,Fan Cui-Song et al. Three-dimensional tensor controlled-source electromagnetic modeling based on the vector finite-element method[J]. APPLIED GEOPHYSICS, 2015, 12(1): 35-46.
[1]
Boerner, D. E., Wright, J. A., Thurlow, J. G., and Reed, L. E., 1993, Tensor CSAMT studies at the Buchans Mine in central Newfoundland: Geophysics, 58(1), 12−19.
[2]
Bromley, C., 1993, Tensor CSAMT study of the fault zone between Waikite and Te Kopia geothermal fields: Journal of Geomagnetism and Geoelectricity, 45(9), 887−896.
[3]
Fan, C. S., 2013, Research on complex resistivity forward and invertion with finite element and its application: Doctor’s thesis, Jilin University.
[4]
Hu, X. Y., Peng, R. H., Wu, G. J., Wang, G. J., Wang, W. P., Huo, G. P., and Han, B., 2012, Mineral Exploration using CSAMT data: Application to Longmen region metallogenic belt, Guangdong Province, China: Geophysics, 78(3), B111−B119.
[5]
Jin, J. M., 1998, Finite element method of electromagnetic field: Xi’an Electronic University Press, 164−200.
[6]
Li, X. B., Pedersen, and L. B., 1991, Controlled Source Tensor Magnetotellurics: Geophysics, 56(9), 1456−1461.
[7]
Lin, C. H., Tan, H. D., and Tong, T., 2009, Three-dimensional conjugate gradient inversion of magnetotelluric full information data: Applied Geophysics, 8(1), 1−10.
[8]
Liu, C. S., Ren, Z. Y., Tang, J. T., and Yan, Y., 2008, Three-dimensional magnetotellurics modeling using edge-based finite-element unstructured meshes: Applied Geophysics, 3, 170−180.
[9]
Meng, Q. K., Lin, P. R., and Xu, B. L., 2013, Study of one-dimensional numerical simulation of tensor CSAMT: Computing Techniques for Geophysical and Geochemical Exploration, 35(4), 435−441.
[10]
Mukherjee, S., and Everett, M. E., 2011, 3D controlled-source electromagnetic edge-based finite element modeling of conductive and permeable heterogeneities: Geophysics, 76(4), F215−F226.
[11]
Nam, M. J., Kim, H. J., Song, Y., Lee, T. J., and Son, J. S., 2007, 3D magnetotelluric modeling including surface topography: Geophysics, 55, 277−287.
[12]
Silva, N. V., Morgan, J. V., MacGregor, L., and Warner, M., 2012, A finite element multifrontal method for 3D CSEM modeling in the frequency domain: Geophysics, 77(2), E101−E115.
[13]
Wang, Y., 2008, A study of 3D high frequency magnetotellurics modeling by edge-based finite element method: Doctor’s thesis, Central South University, Hunan.
[14]
Wang, S. M., Li, D. S., and Hu, H., 2013, Numerical modeling of magnetotelluric tensor in the context of 3D/3D formation: Chinese Journal of Geophysics (in Chinese), 56(5), 1745−1752.
[15]
Wang, X. X., Di, Q. Y., and Xu, C. 2014, Characteristics of multiple sources and tensor measurement in CSAMT: Chinese Journal of Geophysics (in Chinese), 57(2), 651−661.
[16]
Wannamaker, P. E., 1997a Tensor CSAMT survey over the Sulphur Springs thermal area, Valles Caldera, New Mexico, United States of America, Part I: Implications for structure of the western caldera: Geophysics, 62(2), 451−465.
[17]
Wannamaker, P. E., 1997b, Tensor CSAMT survey over the Sulphur Springs thermal area, Valles Caldera, New Mexico, United States of America, Part II : Implications for CSAMT methodology: Geophysics, 62(2), 466−476.
[18]
Wu, L. P., Shi, K. F., and Li, Y. H., 1996, Application of CSAMT to the search for ground water: Chinese Journal of Geophysics (in Chinese), 39(5), 712−717.
[19]
Xu, S. Z., 1994, The finite-element method in Geophysics: Science Press, Beijing, 238−254.
[20]
Tan, H. D., We, W. B., Deng, M., and J, S., 2004, General use formula in MT tensor impedance: Oil geophysical prospecting, 39(1), 113−116.
[21]
Xu, Z. F., and Wu, X. P., 2010, Controlled source eletromagnetic 3-D modeling in frequency domain by finite element method: Chinese Journal of Geophysics (in Chinese), 53(8), 1931−1939.
[22]
Yu, C. M., 1998, The application of CSAMT method in looking for hidden gold mine: Chinese Journal of Geophysics (in Chinese), 41(1), 133−138.
[23]
Zhang, J. F., Tang, J. T., Yu, Y., Wang, Y., Liu, C. S., and Xiao, X., 2009, Three dimensional controlled source eletromagnetic numerical simulation based on electric field vector equation using finite element method: Chinese Journal of Geophysics (in Chinese), 52(12), 3132−3141.
2015, Vol. 12 
