1. College of Geological Engineering and Geomatics, Chang’an University, Xi’an 710054, China 2. National Engineering Research Center of Offshore Oil and Gas Exploration, Beijing 100028, China 3. Integrated Geophysical Simulation Laboratory, Chang’an University, Xi’an 710054, China
The transient electromagnetic method (TEM) commonly uses the all-time apparent resistivity parameter for interpretation, which involves complex formulas and time-consuming iterative processes. Based on the characteristics of TEM data, this study employed the artificial neural network (ANN) for TEM pseudo-resistivity imaging. First, this study designed a multi-hidden-layer BP neural network and calculated a response amplitude through TEM analysis. The response amplitude, as the mapping parameter of pseudo resistivity, was used for network training. Then new data outside the training set were used to test the trained network. A homogeneous half-space and one-dimensional layered model was built to verify the correctness and adaptability of the neural network. The imaging of the three-dimensional geoelectric model was performed. As revealed by the results, the pseudo resistivity calculated based on the neural network can reflect the target anomalies of the geoelectric model, with highly accurate network imaging results. Finally, the measured data were processed using the neural network algorithm, further indicating that the neural network-based imaging can serve as a basis for data interpretation. This study verified the feasibility of the ANN in TEM imaging, thus providing a new approach for TEM imaging.
Lyu G Y. Current status and development trend of transient EM method[J]. Computing Techniques for Geophysical and Geochemical Exploration, 2007, 10(S1):111-115,10.
[3]
Fullagar P K. Generation of conductivity-depth pseudo-sections from coincident loop and in-Loop TEM data[J]. Australian Society of Exploration Geophysicists (ASEG), 1989, 20(1/2): 43-45.
Chen B C, Mou Y G, Sun J D. Fast inversing imaging technique and softwares for data of transient electromagnetic method[J]. Geophysical and Geochemical Exploration, 2000, 24(5):377-382,386.
[5]
Fullagar P K, Reid J E. Emax conductivity-depth transformation of airborne TEM data[J]. ASEG Extended Abstracts, 2001(1): 1-4.
Yan L J, Xu S Z, Hu W B, et al. A rapid resistivity imaging method for central loop transient electromagnetic sounding and its application[J]. Coal Geology & Exploration, 2002, 30(6): 58-61.
Fan Y N, Li X, Qi Z P, et al. Study on Born approximation algorithm of TEM pseudo wave-field[J]. Progress in Geophysics, 2019, 34(2): 529-536.
[11]
Spichak V, Fukuoka K, Kobayashi T, et al. ANN reconstruction of geoelectrical parameters of the Minou fault zone by scalar CSAMT data[J]. Journal of Applied Geophysics, 2002, 49(1): 75-90.
doi: 10.1016/S0926-9851(01)00100-8
[12]
Singh U K, Tiwari R K, Singh S B. One-dimensional inversion of geo-electrical resistivity sounding data using artificial neural networks—A case study[J]. Computers and Geosciences, 2005, 31(1):99-108.
doi: 10.1016/j.cageo.2004.09.014
[13]
谢林涛. 瞬变电磁快速成像方法的研究[D]. 重庆: 重庆大学, 2009.
[13]
Xie L T. Research on fast inversing imaging method for transient electromagnetic method[D]. Chongqing: Chongqing University, 2009.
Zhu K G, Ma M Y, Che H W, et al. PC-based artificial neural network inversion for airborne time-domain electromagnetic data[J]. Applied Geophysics, 2012, 9(1):1-8,114.
doi: 10.1007/s11770-012-0307-7
[15]
李栋. 基于人工神经网络的航空瞬变电磁拟电阻率成像方法研究[D]. 西安: 长安大学, 2019.
[15]
Li D. Study on airborne transient electromagnetic quasi-resistivity imaging method based on artificial neural network[D]. Xi’an: Chang’an University, 2019.
[16]
Noh K, Yoon D, Byun J. Imaging subsurface resistivity structure from airborne electromagnetic induction data using deep neural network[J]. Exploration Geophysics, 2020, 51 (2),214-220.
doi: 10.1080/08123985.2019.1668240
Wu G P, Zhang Y Y, Zhang B W, et al. The calculation of full-region apparent resistivity of central loop TEM based on deep learning[J]. Geophysical and Geochemical Exploration, 2021, 45(3):750-757.
[18]
白旸. 基于小波神经网络的航空瞬变电磁成像方法研究[D]. 西安: 长安大学, 2021.
[18]
Bai Y. Study on airborne transient electromagnetic imaging method based on wavelet artificial neural network[D]. Xi’an: Chang’an University, 2021.
Yang Z F, Tian R F, Xiao X, et al. The application pseudo-resistivity reconstruction to identify oil layers in lithologic reservoir[J]. Science Technology and Engineering, 2014, 14(7):117-120.