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Artificial neural network-based transient electromagnetic imaging |
YOU Xi-Ran1( ), ZHANG Ji-Feng1,2,3( ), SHI Yu1 |
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 |
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Abstract 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.
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Received: 08 November 2022
Published: 27 October 2023
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Corresponding Authors:
ZHANG Ji-Feng
E-mail: chdyxr@163.com;zjf0201@126.com
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发射电 流/A | 发射半 径/m | 采样时 间/s | 电阻率范 围/(Ω·m) | 时间道数 | 20 | 1.8 | 10-6~10-1 | 1~1000 | 101 |
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Parameters of training data
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Structure diagram of the three-layer BP neural network
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Structural diagram of neural network with transient electromagnetic pseudo resistivity
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Calculation results of uniform half space model with different parameters
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模型 | ρ/(Ω·m) | 平均相对 误差E/% | 拟合优 度R | 时间道数 | a | 10 | 2.15 | 0.9997 | 40 | b | 100 | 1.90 | 0.9998 | 40 | c | 1000 | 1.97 | 0.9998 | 40 |
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Measurement index of half-space model
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模型 | 层厚/m | ρ/(Ω·m) | 模型 | 层厚/m | ρ/(Ω·m) | G型 | 50 Inf | 10 100 | D型 | 50 Inf | 100 10 |
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Parameters of two-layer model
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Calculation results of two-layer mode
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模型 | ρ/(Ω·m) | 平均相对 误差E/% | 拟合优 度R | 时间道数 | G型 | 10-100 | 10.79 | 0.9734 | 101 | D型 | 100-10 | 7.30 | 0.9923 | 101 |
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Measurement index of the two-layer model
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模型 | 层厚/m | ρ/(Ω·m) | 模型 | 层厚/m | ρ/(Ω·m) | H型 | 50 100 Inf | 100 10 100 | K型 | 50 100 Inf | 10 100 10 | 模型 | 层厚/m | ρ/(Ω·m) | 模型 | 层厚/m | ρ/(Ω·m) | A型 | 50 100 Inf | 10 100 500 | Q型 | 50 100 Inf | 500 100 10 |
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Parameters of three-layer model
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模型 | ρ/(Ω·m) | 平均相 对误差E/% | 拟合优 度R | 时间道数 | H型 | 100-10-100 | 20.18 | 0.9790 | 101 | K型 | 10-100-10 | 17.22 | 0.9488 | 101 | A型 | 10-100-500 | 25.78 | 0.8054 | 101 | Q型 | 500-100-10 | 20.21 | 0.9764 | 101 |
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Measurement index of the three-layer model
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Calculation results of the three-layer model
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Diagram of 3D model
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Calculation results of 3D model
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Survey line location map
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Calculation results of measured data
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Profile after removing background value
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