An anti-anchor interference downhole transient electromagnetic detection coil device

Abstract

This utility model discloses a downhole transient electromagnetic detection coil device resistant to anchor bolt interference, belonging to the field of transient electromagnetic detection technology. The device includes an anchor bolt, a test roadway, and a transceiver coil. The test roadway has a left sidewall on one side and a right sidewall on the other. Three sets of boreholes are located inside the left sidewall. To address the issue of abnormal interference in existing transient electromagnetic detection technology during actual detection, which affects the accuracy of the detection data, the transient electromagnetic advance detection system should move the loop as much as possible during on-site data acquisition to avoid anchor bolts on the working face being distributed within 1.5m of the center of the loop. If this cannot be avoided, the loop should first be moved so that the anchor bolt is located outside the loop, then at the center of the loop, and finally at the boundary of the loop. This reduces the anchor bolt response and further reduces anchor bolt interference.

Description

Technical Field

[0001] This utility model relates to the field of transient electromagnetic detection technology, specifically to a downhole transient electromagnetic detection coil device that is resistant to anchor bolt interference. Background Technology

[0002] Currently, geophysical exploration methods used to detect water sources posing a potential water hazard threat to coal mines mainly include direct current (DC) electrical resistivity tomography (DCOS), transient electromagnetic (TEM) methods, radio wave imaging, ground penetrating radar (GPR), and seismic exploration methods. DCOS exploration depth is limited when the length of the working roadway is finite, and TEM is ineffective if the working face does not form a systematic network. Transient electromagnetic (TEM) methods, employing non-contact detection technology, can overcome the limitations of underground working space and have a very broad application prospect.

[0003] Existing transient electromagnetic detection technologies are susceptible to abnormal interference during actual detection processes, which can affect the accuracy of the detection data. Utility Model Content

[0004] The purpose of this invention is to provide a downhole transient electromagnetic detection coil device that resists anchor bolt interference. When collecting data in the field, the transient electromagnetic probe should be moved as much as possible to avoid anchor bolts on the working face being distributed within 1.5m of the center of the probe. If this cannot be avoided, the probe should first be moved so that the anchor bolt is located outside the probe, then at the center of the probe, and finally at the boundary of the probe. This can reduce the response of the anchor bolt and further reduce the interference of the anchor bolt, thus solving the problems in the prior art.

[0005] To achieve the above objectives, this utility model provides the following technical solution: a downhole transient electromagnetic detection coil device for resisting anchor bolt interference, comprising an anchor bolt, a test tunnel, and a transceiver coil, wherein a left side of the test tunnel is provided on one side, and a right side of the test tunnel is provided on the other side. The left side of the tunnel has three sets of boreholes inside, and the anchor bolt extends into the interior of the boreholes.

[0006] Preferably, a top plate is provided above the test tunnel, and a bottom plate is provided below the test tunnel.

[0007] Preferably, the transceiver coil is installed between the test tunnel and the floor plate.

[0008] Preferably, the borehole depth is two meters, the test tunnel diameter is three meters, and the length is four meters.

[0009] Compared with the prior art, the beneficial effects of this utility model are:

[0010] 1. In this utility model, when the transient electromagnetic advance probe is collecting data on site, the loop should be moved as much as possible to avoid the anchor rods on the working surface being distributed within 1.5m of the center of the loop. If this cannot be avoided, the loop should first be moved so that the anchor rods are located outside the loop, then the center of the loop, and finally the boundary of the loop. This can reduce the response of the anchor rods and further reduce the interference of the anchor rods. Attached Figure Description

[0011] Figure 1 This is the overall front view of the present invention;

[0012] Figure 2 This is a schematic diagram of the cross-sectional structure of the test tunnel of this utility model.

[0013] In the diagram: 1. Roof; 2. Left side of the tunnel; 3. Right side of the tunnel; 4. Drill hole; 5. Anchor bolt; 6. Test tunnel; 7. Floor; 8. Transceiver coil. Detailed Implementation

[0014] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0015] To address the issue of abnormal interference occurring during actual detection using existing transient electromagnetic detection technologies, which affects the accuracy of the detection data; please refer to... Figure 1-2 The present invention provides the following solution:

[0016] An anti-anchor bolt interference downhole transient electromagnetic detection coil device includes an anchor bolt 5, a test tunnel 6 and a transceiver coil 8. The test tunnel 6 has a left side 2 on one side and a right side 3 on the other side. The left side 2 has three sets of boreholes 4 inside, and the anchor bolt 5 extends into the boreholes 4.

[0017] A top plate 1 is installed above the test tunnel 6, and a bottom plate 7 is installed below the test tunnel 6. A transceiver coil 8 is installed between the test tunnel 6 and the bottom plate 7. The borehole 4 is two meters deep, and the test tunnel 6 has a diameter of three meters and a length of four meters.

[0018] The impact of anchor bolt 5 on the transient electromagnetic detection distance was determined through physical model experiments conducted in an underground rock tunnel without interference from other metals.

[0019] The maximum interference distance of anchor bolt 5 is d = 3m. Beyond this distance, the interference from anchor bolt 5 is negligible. Within this distance, when 1.5 ≤ d ≤ 3m, the interference is weak; however, when 0 ≤ d ≤ 1.5m, the interference (UI) increases significantly, and the interference is strong. Specifically, the interference decreases exponentially from the center of the loop towards the boundary and outwards, reaching its maximum at the boundary of the loop, up to 102.3 μV / A. Furthermore, the response of anchor bolt 5 also follows a certain pattern with its exposed length L: the interference is minimal when L = 0m, and maximum when L = 1.4m. When L increases by 0.5m from 0, the interference signal amplitude increases rapidly, and when L increases from 0.5m to 1.7m, the interference is essentially at its strongest.

[0020] According to the experimental results of the physical model of transient electromagnetic advance detection interference factors, it can be seen that metal objects at the tunnel face have a significant impact on electromagnetic advance detection. The transient electromagnetic advance detection is particularly affected by metal interference. Any iron objects near the coil at the tunnel face will affect the transient electromagnetic detection results and have a significant impact on the detection results.

[0021]

[0022]

[0023] When collecting data in the field, the loop line should be moved as much as possible to avoid the anchor bolts on the working surface being distributed within 1.5m of the center of the loop line. If this cannot be avoided, the loop line should first be moved so that the anchor bolts are located outside the loop line, then the center of the loop line, and finally the boundary of the loop line. This can reduce the response of the anchor bolts and further reduce the interference of the anchor bolts.

[0024] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0025] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A downhole transient electromagnetic detection coil device resistant to anchor bolt interference, characterized in that, It includes anchor bolts (5), test tunnel (6) and transceiver coils (8). The test tunnel (6) has a left sidewall (2) on one side and a right sidewall (3) on the other side. The left sidewall (2) has three sets of boreholes (4) inside, and the anchor bolts (5) extend into the boreholes (4).

2. The downhole transient electromagnetic detection coil device for resisting anchor bolt interference according to claim 1, characterized in that: The test tunnel (6) is provided with a top plate (1) above it and a bottom plate (7) below it.

3. The downhole transient electromagnetic detection coil device for resisting anchor bolt interference according to claim 2, characterized in that: The transceiver coil (8) is installed between the test tunnel (6) and the bottom plate (7).

4. The downhole transient electromagnetic detection coil device for resisting anchor bolt interference according to claim 1, characterized in that: The borehole (4) is two meters deep, and the test tunnel (6) is three meters in diameter and four meters in length.

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