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Mine transient electromagnetic detection device and method based on u-shaped helical source

A detection device and transient electromagnetic technology, which is applied in the direction of electrical/magnetic detection for logging records, etc., can solve the problems of reducing detection accuracy and resolution, increasing tool off time, and large size of transmitting coil, etc. Achieve the effect of reducing detection blind area, improving detection accuracy and resolution, and reducing mutual inductance

Inactive Publication Date: 2017-08-25
NORTH CHINA INST OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] (1) Poor anti-interference ability, underground detection has the characteristics of complex interference sources (including industrial electricity, rails, bolts, roadheaders, etc.); multi-turn square loop sources are easily affected by interference sources near the coil, which will reduce detection accuracy and resolution
[0006] (2) The mutual inductance between the transmitting coil and the receiving coil is strong, which will increase the shutdown time of the instrument and cause a detection blind zone of about 20m
[0007] (3) The size of the transmitting coil is relatively large, which limits the application in narrow roadway space

Method used

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  • Mine transient electromagnetic detection device and method based on u-shaped helical source
  • Mine transient electromagnetic detection device and method based on u-shaped helical source
  • Mine transient electromagnetic detection device and method based on u-shaped helical source

Examples

Experimental program
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Effect test

Embodiment 1

[0041] In order to illustrate the anti-interference ability of the present invention and the effect of reducing the off time, the present invention provides a test comparison result between the traditional square loop source detection device and the present invention.

[0042] Parameter setting of multi-turn square loop source and U-shaped spiral source in the embodiment:

[0043] The multi-turn square loop source adopts a square bracket with a side length of 2m, and the power supply wire is 512m long. It is wound on the square bracket in a tightly wound spiral manner, leaving 2.5m at each end to connect to the transmitter (combined attached) figure 1 ).

[0044] The U-shaped bracket 1-1 of the U-shaped spiral source is composed of two straight pipes 1-12 and a semicircular elbow pipe 1-11. The materials are all PVC, straight pipes 1-12 and semicircular elbow pipes. 1-13 is connected by a threaded interface; the two straight pipes 1-12 have the same size, with an outer diameter of 16...

Embodiment 2

[0049] In order to illustrate the effectiveness of the mine transient electromagnetic detection device and method based on the U-shaped spiral source, the present invention provides a certain field detection result.

[0050] The floor rock of a coal seam is mainly composed of sandstone, mudstone and limestone. The limestone is Ordovician limestone, with an average distance of 40m from the coal seam floor and an average thickness of 42m. The karst fissure water in the Ordovician limestone is the main water source. In order to ascertain the stratum and hydrogeological conditions of the roadway floor and eliminate the hidden danger of water hazards, underground transient electromagnetic detection was carried out. This detection adopts the mine transient electromagnetic detection device and method based on the U-shaped spiral source of the present invention. In this survey, a 100m length survey line was arranged as needed, and a survey point was set at a distance of 10m. A total of ...

Embodiment 3

[0053] Take the data processing of No. 6 measuring point (at the station number 60m) in Example 2 as an example to demonstrate the data processing method.

[0054] After the data collection is completed, the original data of No. 6 measuring point (stake number 60m) is shown in Table 1, including the sampling time and magnetic field intensity value of 30 time gates. First calculate the apparent resistivity and depth of the first sampling point. The calculation process is as follows:

[0055] (1) Given the initial value interval of binary search [ρ a =1Ω·m,ρ b =500Ω·m], the minimum relative error ε min = 0.01.

[0056] (2) Calculate the median resistivity ρ 1 =(ρ a +ρ b ) / 2=250.5Ω·m, put into the half-space forward equation B zm (i)=f[ρ i ,t()i]Calculate the theoretical magnetic induction intensity B corresponding to the median resistivity zm (i) = 1.5e-013T.

[0057] (3) Calculate the observation value B z (i)=6.7e-012T and theoretical value B zm (i) = The relative error between 1....

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Abstract

The invention relates to a mine transient electromagnetic detection apparatus and method based on a U-shaped helical source. An emission coil is provided with a non-conductive U-shaped support and a power supply wire, the power supply wire is wound on the U-shaped support in a closely winding helical mode, the start point of the power supply wire is arranged at one end of the U-shaped support, the terminal point of the power supply wire is arranged at the other end of the U-shaped support, the two ends each reserve a 2-3-meter connecting line for connection with an emitter, and the emission coil and a receiving coil maintain an interval of 1 to 5 meters; and the emitter and a host are distanced one meter away from the emission coil and the receiving coil, and area-wide apparent resistivity is calculated based on a binary search algorithm. According to the invention, by use of the U-shaped helical source, interference caused by an interference source nearby the emission coil to a primary field is reduced, and the data quality, the detection precision and the resolution are improved; mutual inductance between the emission coil and the receiving coil is reduced, i.e., the turn-off time and the detection blind area are reduced; the dimension of the emission coil is reduced, and the emission coil is better adapted to a small tunnel space; and the calculation result is accurate, the structure is simple, and the realization is easy.

Description

Technical field [0001] The invention relates to the field of geology and exploration geophysics, in particular to a mine transient electromagnetic detection device and method based on a U-shaped spiral source. Background technique [0002] Transient Electromagnetic Method (TEM) is a time-domain artificial source electromagnetic detection method based on the principle of electromagnetic induction. It uses an ungrounded loop or grounded wire to launch a primary field into the ground. After the primary field is turned off, it measures the changes in the induced secondary field generated by the underground medium over time to find various geological targets. Exploration methods. When the transient electromagnetic method is applied to underground mine detection, it is called Mine Transient Electromagnetic Method (MTEM). [0003] At present, in mine transient electromagnetic detection, the main observation systems are center loop method, overlap loop method and dipole method. figure 1 ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01V3/28
CPCG01V3/28
Inventor 李飞尹尚先张超刘德民潘建旭韩永杨德方郑贵强
Owner NORTH CHINA INST OF SCI & TECH