Low-frequency large-span electromagnetic wave CT data correction method
A data correction, electromagnetic wave technology, applied in electromagnetic wave detection, electrical/magnetic exploration, radio wave measurement system, etc. To solve problems such as large error in the simulation, to reduce the cost of inspection, improve the control of construction quality, and improve the efficiency of inspection
Pending Publication Date: 2022-04-19
中国电波传播研究所
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Problems solved by technology
[0004] Aiming at the problem that the existing ray theory inversion cannot be directly applied to low-frequency and large-span electromagnetic wave CT technology, this invention proposes a new large-span electromagnetic wave CT data correction method based on the propagation characteristics of low-frequency electromagnetic waves in layered media. It is to solve the problem that the existing ray theory is too large for the inversion error of low-frequency measurement data, and cannot satisfy the problem of low-frequency cross-hole electromagnetic tomography data interpretation below 1MHz
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Embodiment 1
[0031] Embodiment 1. This embodiment discloses a data correction method for low-frequency and large-span electromagnetic wave CT detection. Based on the propagation characteristics of low-frequency electromagnetic waves in layered media, the absorption coefficient of the ground surface and the absorption coefficient in the hole are respectively calculated, which is applicable to 1MHz The following low-frequency detection data correction includes the following steps:
[0032] Step 1, calculate the initial field strength E of the launch 0 , Surface absorption coefficient α d and the absorption coefficient α in the borehole h :
[0033] Such as image 3 As shown, the transmitting antenna is placed at the opening of the borehole ZK1, and the receiving antenna is placed at the openings of the drilling holes ZK2 and ZK3 adjacent to the drilling hole ZK1. The low-frequency electromagnetic waves emitted by the transmitting antenna are received by the receiving antenna. All propaga...
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The invention discloses a low-frequency large-span electromagnetic wave CT data correction method, which comprises the following steps of: 1, calculating emission initial field intensity, a ground surface absorption coefficient and a borehole absorption coefficient: calculating the emission initial field intensity, the distance from an emission antenna in a borehole to an orifice and the distance from a receiving antenna in the borehole to the orifice according to the emission initial field intensity, the ground surface absorption coefficient and the borehole absorption coefficient; the field intensity propagating along the drill hole and the field intensity propagating along the drill hole are solved, and the corrected field intensity of the low-frequency electromagnetic wave propagating linearly in the medium in the shortest distance is obtained. According to the correction method disclosed by the invention, the problem of poor inversion effect of low-frequency cross-hole electromagnetic wave CT measurement data is solved, the application of the low-frequency cross-hole electromagnetic wave CT technology in a large hole pitch of 20-40m is realized, the detection efficiency is improved, and the detection cost is reduced.
Description
technical field [0001] The invention belongs to the field of electromagnetic wave CT data processing, in particular to a low-frequency large-span electromagnetic wave CT data correction method in the field. Background technique [0002] Such as figure 1 The cross-hole electromagnetic wave CT technology shown is a method of measuring the electromagnetic wave receiving voltage at different positions by changing the positions of the transmitting antenna and receiving antenna placed in two boreholes (wells), and then using the ray propagation theory to obtain the resistance between the two holes. rate profile techniques such as figure 2 As shown, this technology can be used for cave detection in urban underground space development. [0003] The operating frequency range of trans-bore electromagnetic wave CT is 100KHz to 30MHz, but due to the abnormal data processing results of low frequency (below 1MHz), it cannot meet the engineering requirements, and the working frequency a...
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Login to View More IPC IPC(8): G01V3/30G01V3/38
CPCG01V3/30G01V3/38
Inventor 姬勇力李智强王华雄宋加加
Owner 中国电波传播研究所