A downhole radio wave detection apparatus and method

Abstract

The application discloses a kind of downhole radio wave detection device and method, including transceiving coil, coil rotation control unit, wave form emission and receiving unit and control unit;The transceiving coil is composed of X direction transmitting coil, Y direction receiving coil and Z direction receiving coil, and X direction transmitting coil is arranged orthogonally with Y direction receiving coil and Z direction receiving coil two by two respectively, and the coil rotation control unit includes high-precision stepping motor and stepping motor control circuit, for driving transceiving coil whole to carry out arbitrary angle rotation.The application uses radio wave reflection principle.When abnormal area is close to emission side, signal propagation path is short, attenuation is small, and can be effectively captured by receiving coil, which avoids the defect that transmission signal cannot reach receiving point under large-width working face.

Description

Technical Field

[0001] This invention relates to the field of geophysical exploration technology in mines, specifically to an underground radio wave detection device and method. Background Technology

[0002] In the field of mine geophysical exploration, radio wave imaging is a core device based on the principle of electromagnetic induction. It uses the principle of radio wave imaging to transmit a specific frequency signal through a transmitter at the transmission point. When the signal passes through anomaly areas (such as faults and collapse columns) in the underground working face, it will be attenuated. The receiving coil on the other side receives the remaining signal and analyzes the signal attenuation law to detect the structure of the anomaly area. This technology has been widely used in the geological condition detection of conventional coal seam working faces.

[0003] However, existing downhole radio wave imaging devices consist of independent transmitting coils, independent receiving coils, and matching transmitters and receivers. When facing detection scenarios involving large and wide working faces, they have significant technical shortcomings, as follows:

[0004] When the working face is wide and the abnormal area is located on the transmitting side, the path that the radio wave signal needs to travel is too long. After being attenuated by the geological medium, the intensity of the transmitted signal is greatly reduced and cannot reach the receiving point on the other side, resulting in the complete failure to detect the abnormal area and failing to provide effective early warning for subsequent safe production.

[0005] Existing radio wave imaging methods transmit signals from a single transmitting point, with receiving points distributed in a fan shape around the transmitting point to receive the signals, similar to the principle of human CT scans to analyze abnormal areas. However, since the size of the abnormal area is unknown beforehand, the fan shape may not be completely covered, or the number of electromagnetic lines passing through the abnormal area may be insufficient, leading to a large error in judging the shape of the abnormal area. This is especially true when there are multiple anomalous areas distributed at intervals, which are easily misjudged as a single anomalous area, seriously affecting the accuracy of detection.

[0006] Therefore, we propose a downhole radio wave detection device and method. Summary of the Invention

[0007] The purpose of this invention is to provide a downhole radio wave detection device and method, which solves the problems mentioned in the background art.

[0008] To achieve the above objectives, the present invention provides the following technical solution: a downhole radio wave detection device, characterized in that it includes a transceiver coil, a coil rotation control unit, a waveform transmission and reception unit, and a control unit;

[0009] The transceiver coil consists of a transmitting coil in the X direction, a receiving coil in the Y direction, and a receiving coil in the Z direction, with the transmitting coil in the X direction arranged orthogonally to the receiving coils in the Y and Z directions, respectively.

[0010] The coil rotation control unit includes a high-precision stepper motor and a stepper motor control circuit, which is used to drive the entire transceiver coil to rotate at any angle;

[0011] The waveform transmitting and receiving unit contains a full-bridge PWM driving circuit and an LC resonant circuit, which are used to convert the input specific frequency PWM waveform into a sine wave and amplify the power to realize signal transmission, while receiving the reflected signals transmitted by the Y-direction receiving coil and the Z-direction receiving coil.

[0012] The control unit includes a processor and an ADC acquisition circuit. The ADC acquisition circuit includes ADC1 and ADC2. ADC1 is used to acquire the signal received by the Y-direction receiving coil, and ADC2 is used to acquire the signal received by the Z-direction receiving coil. The processor is used to control the generation of PWM waveform, the driving of the stepper motor, and the operation of the ADC acquisition circuit. It also performs vector synthesis on the signals acquired by ADC1 and ADC2 to obtain the response signal intensity of the target geological body.

[0013] In a preferred embodiment of the present invention, the processor is an FPGA or a DSP.

[0014] This invention also relates to a downhole radio wave detection method, comprising the following steps:

[0015] Step 1: Set the transmitting point and receiving point on the same side and in the same location in the underground roadway, so that the transmitting point transmits radio wave signals while the receiving point simultaneously receives the reflected signals;

[0016] Step 2: Control the transmitting and receiving points to scan synchronously around the point from 0° to 180°, with the scanning interval set according to the detection requirements;

[0017] Step 3: After completing the scanning of the current transmit-receive point, move the underground radio wave detection device to the next preset point and repeat Step 2 until the detection of the entire tunnel to be detected is completed.

[0018] Step 4: Using the ray tracing principle of radio wave perspective, calculate the amplitude of the ray reflection signal corresponding to different scanning angles at each detection point, draw contour lines based on the amplitude of the reflection signal, and then delineate the abnormal area.

[0019] In a preferred embodiment of the present invention, step 4 uses the formula The signals acquired by ADC1 and ADC2 are vector synthesized, where B Y B is the magnetic field strength induced by the receiving coil in the Y direction. Z B is the magnetic field strength induced by the receiving coil in the Z direction, and B is the magnetic field strength at the corresponding spatial point of the target geological body.

[0020] In a preferred embodiment of the present invention, the scanning interval in step 2 is set to any angle value that meets the detection accuracy requirements.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0022] This invention differs from existing technologies that rely on the transmission principle; instead, it employs the principle of radio wave reflection. When an abnormal area is close to the transmitting side, the signal propagation path is short and attenuation is small, allowing it to be effectively captured by the receiving coil. This avoids the defect that transmitted signals cannot reach the receiving point under a large working surface.

[0023] Abandoning the traditional separate transceiver coils, a transceiver coil structure with X, Y, and Z pairs of orthogonal coils is adopted. Combined with a vector synthesis algorithm, direct wave interference from the transmitting coil can be completely filtered out, retaining only the reflected signal from the abnormal area, significantly improving the signal acquisition accuracy and providing a reliable data basis for judging the morphology of the abnormal area.

[0024] By controlling the coil rotation with a high-precision stepper motor, scanning at any angle from 0° to 180° and above can be achieved. Compared with the traditional fixed fan-shaped receiving method, it can more comprehensively cover all directions of space, effectively avoid missing detection of abnormal areas, and is especially suitable for distinguishing and detecting multiple abnormal areas. Attached Figure Description

[0025] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0026] Figure 1 This is a schematic diagram of the integrated transceiver coil of the present invention;

[0027] Figure 2 This is a schematic diagram of the radio wave transmission method of the present invention. Detailed Implementation

[0028] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0029] like Figure 1-2 As shown, a downhole radio wave detection device is specifically described below:

[0030] It includes a transceiver coil, a coil rotation control unit, a waveform transmission and reception unit, and a control unit;

[0031] The transceiver coil consists of a transmitting coil in the X direction, a receiving coil in the Y direction, and a receiving coil in the Z direction, with the transmitting coil in the X direction arranged orthogonally to the receiving coils in the Y and Z directions, respectively.

[0032] The coil rotation control unit includes a high-precision stepper motor and a stepper motor control circuit, which is used to drive the entire transceiver coil to rotate at any angle;

[0033] The waveform transmitting and receiving unit contains a full-bridge PWM driving circuit and an LC resonant circuit, which are used to convert the input specific frequency PWM waveform into a sine wave and amplify the power to realize signal transmission, while receiving the reflected signals transmitted by the Y-direction receiving coil and the Z-direction receiving coil.

[0034] The control unit includes a processor and an ADC acquisition circuit. The ADC acquisition circuit includes ADC1 and ADC2. ADC1 is used to acquire the signal received by the Y-direction receiving coil, and ADC2 is used to acquire the signal received by the Z-direction receiving coil. The processor is used to control the generation of PWM waveform, the driving of the stepper motor, and the operation of the ADC acquisition circuit. It also performs vector synthesis on the signals acquired by ADC1 and ADC2 to obtain the response signal intensity of the target geological body. The processor is an FPGA or a DSP.

[0035] Coil assembly: The X-direction transmitting coil, Y-direction receiving coil, and Z-direction receiving coil are fixed on the same bracket in pairs orthogonal (with an included angle of 90°) to ensure that the normal direction of the coil plane is accurately aligned with the X, Y, and Z axes, thereby reducing the impact of assembly errors on signal acquisition;

[0036] Circuit connection: Connect the coil to the waveform transmitting and receiving unit, the coil rotation control unit, and the control unit: connect the X coil to the output terminal of the waveform transmitting unit, and connect the Y and Z coils to the input terminals of the waveform receiving unit respectively; connect the stepper motor to the drive output terminal of the coil rotation control unit; connect the PWM output terminal of the control unit to the waveform transmitting unit, the ADC input terminal to the waveform receiving unit, and the motor control signal output terminal to the coil rotation control unit;

[0037] System debugging: After powering on, set the transmission signal frequency (e.g., 100kHz-1MHz, selected according to the geological conditions of the coal seam) and scanning angle interval (e.g., 2°) through the debugging interface of the control unit; control the stepper motor to drive the coil to rotate, detect whether the received signals of the Y and Z coils are normal, and whether the signal strength calculated by the vector synthesis algorithm is stable. If there is an abnormality, adjust the coil orthogonal angle or circuit parameters until the system runs normally.

[0038] The specific operating method is as follows:

[0039] Detection point layout: On the emitting side of the underground roadway to be detected (such as the sidewall of one side of the roadway), detection points are laid out at preset intervals (such as 5m-10m, determined according to the detection accuracy requirements), and the position coordinates of each point are marked to ensure that the points are evenly distributed along the length of the roadway.

[0040] Fixed-point scanning: The debugged detection device is fixed at the first detection point, and the scanning program is started: The control unit drives the X coil to emit a radio wave signal of a set frequency, and simultaneously controls the stepper motor to drive the coil to rotate from 0° to 180° at set intervals (e.g., 2°). At each rotation angle, ADC1 and ADC2 synchronously acquire the received signals from the Y and Z coils. The control unit performs vector synthesis calculations in real time, using the formula... The signals acquired by ADC1 and ADC2 are vector synthesized, where B Y B is the magnetic field strength induced by the receiving coil in the Y direction. Z Z represents the magnetic field strength induced by the receiving coil in the Z direction, and B represents the magnetic field strength at the corresponding spatial point of the target geological body. The signal strength data corresponding to each angle is stored.

[0041] Mobile detection and data acquisition: After completing the scanning of the first point, the detection device is moved to the next preset point, and the scanning and data acquisition operation is repeated until all points in the entire tunnel to be detected are covered. During this process, the coordinates of each point and the corresponding data file are recorded.

[0042] Data processing and anomaly delineation: Signal intensity data from all points and angles collected downhole are imported into a ground data processing terminal. The reflected signal amplitude of each ray is calculated using a ray tracing algorithm, and a contour map of the signal amplitude is drawn using professional plotting software. Based on the low-value areas of the contour lines (the attenuation of the signal in the anomaly area leads to a decrease in the reflected signal amplitude), the boundaries, size, and shape of the anomaly area are delineated, and a detection report is generated.

[0043] This invention effectively solves the detection failure problem of existing radio wave imaging technology in large-area working faces and near-transmitting areas by adopting an innovative integrated transceiver coil structure design (pairwise orthogonal coils + vector synthesis) and a synchronous fixed-point scanning reflection detection method for radio waves. Simultaneously, it achieves precise delineation of the morphology of abnormal areas. The device and method are simple to operate, have high detection accuracy, and are highly adaptable, further expanding the application scenarios of radio wave detection technology in mine working face structural detection, and providing an efficient and reliable solution for geophysical exploration in complex underground environments.

[0044] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or basic characteristics. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

[0045] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A downhole radio wave detection device, characterized in that: It includes a transceiver coil, a coil rotation control unit, a waveform transmission and reception unit, and a control unit; The transceiver coil consists of a transmitting coil in the X direction, a receiving coil in the Y direction, and a receiving coil in the Z direction, with the transmitting coil in the X direction arranged orthogonally to the receiving coils in the Y and Z directions, respectively. The coil rotation control unit includes a high-precision stepper motor and a stepper motor control circuit, which is used to drive the entire transceiver coil to rotate at any angle; The waveform transmitting and receiving unit contains a full-bridge PWM driving circuit and an LC resonant circuit, which are used to convert the input specific frequency PWM waveform into a sine wave and amplify the power to realize signal transmission, while receiving the reflected signals transmitted by the Y-direction receiving coil and the Z-direction receiving coil. The control unit includes a processor and an ADC acquisition circuit. The ADC acquisition circuit includes ADC1 and ADC2. ADC1 is used to acquire the signal received by the Y-direction receiving coil, and ADC2 is used to acquire the signal received by the Z-direction receiving coil. The processor is used to control the generation of PWM waveform, the driving of the stepper motor, and the operation of the ADC acquisition circuit. It also performs vector synthesis on the signals acquired by ADC1 and ADC2 to obtain the response signal intensity of the target geological body.

2. The downhole radio wave detection device according to claim 1, characterized in that: The processor is either an FPGA or a DSP.

3. A downhole radio wave detection method, applicable to the downhole radio wave detection device according to any one of claims 1-2, characterized in that: Includes the following steps: Step 1: Set the transmitting point and receiving point on the same side and in the same location in the underground roadway, so that the transmitting point transmits radio wave signals while the receiving point simultaneously receives the reflected signals; Step 2: Control the transmitting and receiving points to scan synchronously around the point from 0° to 180°, with the scanning interval set according to the detection requirements; Step 3: After completing the scanning of the current transmit-receive point, move the underground radio wave detection device to the next preset point and repeat Step 2 until the detection of the entire tunnel to be detected is completed. Step 4: Using the ray tracing principle of radio wave perspective, calculate the amplitude of the ray reflection signal corresponding to different scanning angles at each detection point, draw contour lines based on the amplitude of the reflection signal, and then delineate the abnormal area.

4. The downhole radio wave detection method according to claim 3, characterized in that: In step 4, the formula is used. The signals acquired by ADC1 and ADC2 are vector synthesized, where B Y B is the magnetic field strength induced by the receiving coil in the Y direction. Z B is the magnetic field strength induced by the receiving coil in the Z direction, and B is the magnetic field strength at the corresponding spatial point of the target geological body.

5. The downhole radio wave detection method according to claim 3, characterized in that: In step 2, the scanning interval is set to any angle value that meets the detection accuracy requirements.

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