While-drilling transient electromagnetic remote detection system and method based on ground electrical source excitation

Abstract

The invention discloses a while-drilling transient electromagnetic remote detection system and method based on ground electrical source excitation. The system comprises a ground grounding electrical source transmitting module, an underground while-drilling three-component receiving module and a data fusion processing module. The underground while-drilling three-component receiving module can perform full-time three-component magnetic field signal acquisition and keep the spatial consistency of measured data; according to the mining area geologic structure, terrain and interference source distribution, emission source parameters, underground drilling positions and a ground well observation network are designed, a ground electric line source continuously excites a transient electromagnetic field, and the ground well observation network and a while-drilling three-component receiving system conduct full-time collection on electromagnetic response and synchronously transmit the electromagnetic response to a ground work station through optical fibers. And the workstation performs terrain static correction and signal preprocessing on the received signal, and realizes accurate detection of the Ordovician limestone aquifer, integrity evaluation of the grouting curtain and dynamic monitoring of the mining-induced fissure zone by fusing ground-roadway-drilling multi-source data.

Description

Technical Field

[0001] The present invention relates to the field of transient electromagnetic detection, and in particular to a system and method for remote detection of transient electromagnetic while drilling based on ground electrical source excitation. Background Art

[0002] Transient electromagnetic detection technology, an important geophysical exploration tool, works by emitting a primary step electromagnetic field underground through an ungrounded loop or a long grounded conductor. After the excitation source is turned off, it continuously receives the time-varying response signal of the secondary induced eddy current field, thereby inverting the distribution of the electrical characteristics of the underground medium. Compared with other geophysical exploration methods, this technology has significant advantages: deep detection depth (typically up to kilometers), low construction costs (no blasting required), and multi-scenario applicability (covering mineral exploration, structural detection, hydrological and engineering geological surveys, etc.).

[0003] In the field of coal production safety, mine water inrush accidents are characterized by their suddenness and destructive nature. Before mining, the distribution of the Ordovician limestone aquifer and its hidden water-conducting structures must be accurately explored. After floor grouting reinforcement, the integrity of the grouting curtain must be verified. During mining, the development of water-conducting fracture zones under mining-induced stresses must be monitored in real time. However, existing transient electromagnetic technology still faces bottlenecks in meeting these requirements:

[0004] Although the traditional ground transient electromagnetic method has good lateral resolution for low-resistance aquifers, under complex terrain conditions (such as mountains and gullies), the layout of the transmitting and receiving coils is significantly affected by the terrain undulations and is affected by the shielding effect of the high-resistance layer on the surface, making it difficult to obtain reliable response signals from deep targets. The ground electrical source transient electromagnetic method uses a grounded conductor source of several kilometers, which can improve terrain adaptability and enhance deep detection capabilities. However, it is essentially a ground static observation technology and cannot achieve dynamic monitoring of underground working faces during mining. Although existing mine transient electromagnetic method technologies can be implemented underground, their emission magnetic moment is insufficient in confined spaces, the effective detection radius is less than 100m, and they are easily interfered by the induction of metal objects in the tunnel, resulting in large positioning errors for deep targets.

[0005] The recently proposed underground tunnel transient electromagnetic detection method utilizes a trans-spatial observation model, combining high ground transmission power with close-range detection underground. However, underground receiving devices are subject to eddy current interference from strong magnetic conductors such as the tunnel's metal mesh supports and conveyor belts, resulting in insufficient detection accuracy for deep targets. While the recently proposed borehole transient electromagnetic method can shorten detection range and improve vertical resolution, it remains limited by its small transmission magnetic moment and limited detection radius. Currently, these methods struggle to meet the needs of monitoring the development of water-conducting fracture zones in mining-disturbed areas. Summary of the Invention

[0006] Aiming at the above technical deficiencies, the purpose of the present invention is to provide a downhole transient electromagnetic far-detection system and method based on ground electrical source excitation.

[0007] To solve the above technical problems, the present invention adopts the following technical solutions:

[0008] A downhole transient electromagnetic far-detection system based on ground electrical source excitation includes a ground grounded electrical source transmitting module, a downhole drilling-integrated three-component receiving module, and a data fusion and processing module. The ground grounded electrical source transmitting module includes a transmitting source for transmitting transient pulse signals. The downhole drilling-integrated three-component receiving module is integrated in the bit instrument and includes a three-component magnetic sensor, an inertial measurement unit, an internal storage unit, an optical fiber transmission unit, an A / D converter, a MUC system, and a power supply unit for performing full-time three-component magnetic field signal acquisition, maintaining the consistency of axial and radial magnetic field measurements and attitude during the measurement process, receiving axial Ex, Ey, and radial Ez component magnetic field data in real time, storing and transmitting them to the ground through digital conversion. The data fusion and processing module is set up in the ground server to fuse transient electromagnetic data at different observation positions on the ground, in the roadway, and in the borehole, combine high-resolution near-field data with low-resolution far-field data, solve the blind area problem of single-space observation, construct a multi-scale grid model, improve the longitudinal resolution of deep targets, and fuse multi-period observation data in real time during the mining process to analyze the temporal variation of electrical parameters.

[0009] Preferably, the three-component magnetic sensor is installed in a three-component magnetic sensor bin (2), and the three-component magnetic sensor bin (2) is fixed to the bit integrated housing (4) through a dynamic stabilization system.

[0010] Preferably, the bit integrated housing (4) is a titanium alloy forged bit integrated housing with hard alloy cutting teeth at the front end.

[0011] Preferably, the dynamic stabilization system adopts a cross-axis structure and a piezoelectric actuator to achieve the dynamic stabilization of the three-component magnetic sensor bin (2). The bottom of the three-component magnetic sensor bin (2) is integrated with an IMU inertial measurement unit, and static calibration is performed by the six-position method, which can control the sensor swing when the bit azimuth changes to ensure the spatial consistency of the measurement data.

[0012] The present invention also provides a usage method of the above system, which specifically includes the following steps:

[0013] (1) Design the transmitting source and borehole positions, and design the downhole and ground survey lines and grids according to the geological structure conditions, surface undulation conditions, human facilities conditions, and high-voltage line layout conditions in the target detection area.

[0014] (2) The transmitting source sets the transmitting frequency, transmitting current, and transmitting voltage according to the target detection area.

[0015] (3) At each measuring point in the underground and surface measurement networks, a nodal transient electromagnetic instrument is set up, and the instrument is started to receive three-component magnetic field signals in real time and transmit them to the ground server;

[0016] (5) The drill bit starts to drill along the designed borehole. At the same time, the built-in receiving system in the drill bit starts to work, receiving three-component magnetic field data in real time and transmitting it to the ground server;

[0017] (6) The data fusion processing module is set up in the ground server. First, the transient decay curves of repeated observations are weighted and superimposed to suppress random noise, automatically eliminate industrial interference, and improve the signal-to-noise ratio. Secondly, static correction is carried out to eliminate the influence of surface undulation based on terrain DEM data;

[0018] (7) Fuse the transient electromagnetic data at different observation positions on the ground, in the roadway, and in the borehole. Before mining, explore the distribution of the Ordovician limestone aquifer and hidden water-conducting structures, and verify the integrity of the grouting curtain after the floor grouting reinforcement project;

[0019] (8) During the mining process, fuse multi-period observation data in real time, analyze the temporal variation of electrical parameters, and obtain the development status of the water-conducting fissure zone in the mining disturbance area.

[0020] Preferably, when designing the position of the emission source in step (1), the included angle between the emission source direction and the main formation structure direction is greater than 45 degrees to maximize the penetration efficiency of the excitation field to the target body.

[0021] Preferably, in step (2), the emission source adopts a grounded long wire source, which is arranged on the ground surface. The emission uses a 30kW inverter power supply, with a trapezoidal wave as the fundamental wave, outputting a transient pulse with a voltage less than or equal to 1000V and a current less than or equal to 50A. It has a built-in air-cooled heat dissipation system, and the emission frequency adopts an adjustable mode. The length of the emission source is 1000 - 2000 meters. The grounded long wire emits a primary step electromagnetic field to the underground, and the underground medium generates a secondary induced eddy current field after the excitation source is turned off.

[0022] Preferably, the cable of the grounded long wire adopts a multi-strand tinned copper core cable with a cross-sectional area greater than 50mm 2 , with a double-layer insulation sheath and is connected in a segmented manner.

[0023] Preferably, the grounding electrode of the emission source adopts a large-area conductive aluminum plate of 2m × 2m, with a thickness of 5mm, galvanized on the surface for corrosion prevention, and a buried depth greater than 3 meters.

[0024] Preferably, when designing the emission source in step (1), in the terrain undulation area with a height difference greater than 10m, the geodetic coordinates and elevation of the emission source at each point are obtained every 50 meters using a high-precision RTK instrument, and the height difference correction of the emission source is carried out during the data processing.

[0025] The beneficial effects of the present invention are as follows:

[0026] 1. The detection depth of the present invention is increased to more than 2000 meters, the signal stability is improved under complex terrain, the signal anti-interference ability and the vertical resolution of data are improved by fusing data from different observation positions, and dynamic monitoring is carried out through the full-time reception method, and multi-period data is fused in real time, so as to obtain the development state of the water-conducting fissure zone in the mining disturbance area.

[0027] 2. The present invention combines the technology while drilling, can realize dynamic monitoring, and at the same time realizes the integration of multi-source data through the data fusion processing module, which can better reduce interference factors and improve the measurement accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0029] Figure 1 is the flow chart of the transient electromagnetic far detection system while drilling excited by the surface electrical source in the present invention;

[0030] Figure 2 is the schematic diagram of the surface electrical source module in the present invention;

[0031] Figure 3 is the schematic diagram of the downhole three-component receiver while drilling in the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0032] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the protection scope of the present invention.

[0033] Embodiment:

[0034] As Figures 1 to 3As shown in the figure, this embodiment provides a downhole transient electromagnetic far-detection system based on a ground electrical source excitation, which includes a ground grounded electrical source transmitting module, a downhole logging three-component receiving module, and a data fusion and processing module. The ground grounded electrical source transmitting module includes a transmitting source for transmitting transient pulse signals. The downhole logging three-component receiving module is integrated in the bit instrument and includes a three-component magnetic sensor, an inertial measurement unit, an internal storage unit, an optical fiber transmission unit, an A / D converter, an MUC system, and a power supply unit, which is used for full-time three-component magnetic field signal acquisition. During the measurement process, the axial and radial magnetic field measurements are kept consistent with the attitude, and the axial Ex, Ey, and radial Ez component magnetic field data are received in real time, stored through digital conversion, and transmitted to the ground. The data fusion and processing module is set up in the ground server, which is used to fuse the transient electromagnetic data at different observation positions on the ground, in the roadway, and in the borehole, combine the high-resolution near-field data with the low-resolution far-field data, solve the blind area problem of single-space observation, construct a multi-scale grid model, improve the longitudinal resolution of deep target bodies, and fuse multi-period observation data in real time during the mining process to analyze the temporal variation of electrical parameters.

[0035] As Figure 2 shown in the figure is the schematic diagram of the ground electrical source module in this embodiment, and its usage method specifically includes the following steps:

[0036] (1) According to the geological structure conditions of the target detection area, namely the coal seam burial depth, rock layer dip angle, surface undulation conditions, human facilities conditions, and high-voltage line layout conditions, reasonably arrange the position of the transmitting source to ensure that the included angle between the direction of the transmitting source and the main tectonic direction of the stratum is greater than 45 degrees, so as to maximize the penetration efficiency of the excitation field to the target body;

[0037] (2) In the terrain undulation area with a height difference greater than 10m, use a high-precision RTK instrument to obtain the geodetic coordinates and elevation of the transmitting source at this point every 50 meters, and correct the height difference of the transmitting source during the data processing;

[0038] (3) Ensure that the length of the transmitting source is 1000m to 2000m. The cable uses a multi-strand tinned copper core cable with a cross-sectional area greater than 50mm 2 , covered with a double-layer insulation sheath, having good tensile strength and voltage resistance, and connected in sections;

[0039] (4) The grounding electrode uses a large-area conductive aluminum plate of 2m×2m, with a thickness of 5mm, galvanized on the surface for anti-corrosion, and the buried depth is greater than 3 meters to ensure that the electrode is driven into the underground wet layer;

[0040] (5) The emission uses a 30kW inverter power supply with a trapezoidal wave as the fundamental wave. According to the actual situation of the survey area, it outputs transient pulses with a voltage less than or equal to 1000V and a current less than or equal to 50A. It has a built-in air-cooled heat dissipation system, and the emission frequency is adjustable to ensure that the penetration depth of the excitation field is satisfied. In this embodiment, according to the actual situation of the survey area, the output transient pulses refer to the transient pulses with corresponding voltages and currents that can be output according to the actual situation of the survey area, which are well-known to those skilled in the art.

[0041] (6) The grounding long wire emits a primary step electromagnetic field into the ground, and the underground medium generates a secondary induced eddy current field after the excitation source is turned off.

[0042] (7) The fiber optic time synchronization module is used to synchronize the emission source and the three-component magnetic field receiving systems at various locations.

[0043] As Figure 3 shown, it is a schematic diagram of a downhole MWD three-component receiver. The downhole MWD three-component receiver includes: drill bit cutting teeth 1, three-component magnetic sensor chamber 2, dynamic stabilization system 3, drill bit integrated housing 4, MCU integrated main board 5, and cable 6.

[0044] The drill bit integrated housing 4 is a forged drill bit integrated housing made of titanium alloy, with hard alloy cutting teeth at the front end. The drill bit as a whole has sufficient compressive strength to meet the drilling requirements of deep wells in complex formations. The inside of the drill pipe is precision machined to form mutually isolated sensor chambers and control main board chambers. The sensor chamber is provided with a shielding layer to ensure structural stability in a strong vibration environment.

[0045] The three-component magnetic sensor chamber integrates three-component magnetoelectric weak magnetic sensors. The chamber body is stabilized in the dynamic stabilization system. The three-component magnetic sensors can simultaneously receive X, Y, and Z three-component magnetic field signals, can automatically collect data for a long time, have a 24-bit resolution for the three-axis magnetic field, and a sampling rate of 20kHz.

[0046] The dynamic stabilization system is realized through a cross-axis structure and a piezoelectric actuator. The bottom of the three-component magnetic sensor chamber 2 integrates an IMU inertial measurement unit, which is statically calibrated by the six-position method and can control the swing of the sensor when the drill bit orientation changes to ensure the spatial consistency of the measurement data.

[0047] The MCU main board integrates a piezoelectric actuator drive module to adjust the actuator displacement in real time; integrates an A / D converter module to convert the received three-component magnetic field signals into digital signals in real time; has an internal storage unit to store the firmware of the MCU, runtime data, and three-component magnetic field signals. The storage system enables information to be continued in time, and when the signal is interrupted, the MCU starts local storage; a power supply unit, the connector connected to the drill bit power system uses a metal-sealed quick-connect joint; a fiber optic transmission system, the data stored in the MUC is transmitted to the ground workstation through the fiber optic for further data processing.

[0048] In this embodiment, the drill bit cutting teeth 1, three-component magnetic sensor chamber 2, dynamic stability system 3, integrated drill bit housing 4, MCU integrated main board 5, cable 6, RTK instrument, emission source, air-cooled heat dissipation system, ground server, three-component magnetic sensor, inertial measurement unit, internal storage unit, optical fiber transmission unit, A / D converter, MUC system, and power supply unit all adopt existing products or structures well-known to those skilled in the art, and the connection or control methods between them also adopt existing connection or control methods well-known to those skilled in the art.

[0049] This embodiment also provides a usage method for the above system, specifically including the following steps:

[0050] (1) According to the geological structure conditions, surface undulation conditions, human facilities conditions, and high-voltage line layout conditions in the target detection area, design the emission source and drilling positions, and design the downhole and surface survey line networks.

[0051] (2) The emission source sets the emission frequency, emission current, and emission voltage according to the target detection area.

[0052] (3) At each measuring point in the downhole and surface survey networks, a node-type transient electromagnetic instrument is set up. The instrument is started to receive three-component magnetic field signals in real time and transmit them to the ground server. Node-type transient electromagnetic instruments capable of receiving data in real time are respectively arranged on the ground and in the roadway, and the magnetic field data of the axial Ex, Ey, and radial Ez components are also received in real time, and are stored and transmitted to the ground through digital conversion.

[0053] (5) The drill bit starts to drill along the designed borehole. At the same time, the built-in receiving system of the drill bit starts to work, receiving three-component magnetic field data in real time and transmitting them to the ground server.

[0054] (6) The data fusion processing module is set up in the ground server. First, the transient decay curves of repeated observations are weighted and superimposed to suppress random noise, automatically eliminate industrial interference, and improve the signal-to-noise ratio. Secondly, static correction is performed to eliminate the influence of surface undulation based on the terrain DEM data.

[0055] (7) Fuse the transient electromagnetic data at different observation positions on the ground, in the roadway, and in the borehole to explore the distribution of Ordovician limestone aquifers and hidden water-conducting structures during mining exploration, and verify the integrity of the grouting curtain after the floor grouting reinforcement project.

[0056] (8) During the mining process, fuse multi-period observation data in real time, analyze the temporal variation of electrical parameters, and obtain the development status of the water-conducting fissure zone in the mining disturbance area.

[0057] The data fusion processing module is set up in the ground server. First, it performs weighted superposition on the transient decay curves of repeated observations to suppress random noise (such as industrial interference) and improve the signal-to-noise ratio of the signal. It fuses the transient electromagnetic data at different observation positions such as the ground, roadway, and borehole, combines the high-resolution near-field data with the low-resolution far-field data, solves the blind area problem of single-space observation, constructs a multi-scale grid model, and improves the vertical resolution of deep target bodies. During the mining process, it fuses multi-period observation data in real time and analyzes the temporal variation of electrical parameters.

[0058] The downhole logging triaxial receiving module can collect full-time triaxial magnetic field signals and maintain the spatial consistency of measurement data. According to the geological structure, terrain, and distribution of interference sources in the mining area, it designs the transmitter parameters, downhole borehole positions, and surface-well observation network. The surface electrical line source continuously excites the transient electromagnetic field, and the surface-well observation network and the logging triaxial receiving system collect the electromagnetic responses in real time and synchronously transmit them to the ground workstation through optical fibers. The workstation performs terrain static correction and signal preprocessing on the received signals, and fuses the multi-source data of the ground-roadway-borehole to achieve accurate detection of the Ordovician limestone aquifer, integrity assessment of the grouting curtain, and dynamic monitoring of the mining-induced fracture zone.

[0059] This embodiment combines the logging technology, can achieve dynamic monitoring, and at the same time realizes the integration of multi-source data through the data fusion processing module, can better reduce interference factors and improve the measurement accuracy. The detection depth of this embodiment is increased to more than 2000 meters, the signal stability is improved under complex terrain, the signal anti-interference ability and the data vertical resolution are improved by fusing data at different observation positions, and dynamic monitoring is carried out through the full-time receiving method, and multi-period data are fused in real time, so that the development state of the water-conducting fracture zone in the mining disturbance area can be better obtained.

[0060] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention is also intended to include these changes and modifications.

Claims

1. A downhole transient electromagnetic far-detection system excited by a ground electrical source, characterized in that It includes a ground grounding electrical source emission module, a downhole logging-while-drilling three-component receiving module, and a data fusion processing module. The ground grounding electrical source emission module includes an emission source for emitting transient pulse signals. The downhole logging-while-drilling three-component receiving module is integrated in the bit instrument and includes a three-component magnetic sensor, an inertial measurement unit, an internal storage unit, an optical fiber transmission unit, an A / D converter, a MUC system, and a power supply unit, which is used for full-time three-component magnetic field signal acquisition, ensuring that the axial and radial magnetic field measurements are consistent with the attitude during the measurement process, and receiving the axial Ex, Ey, and radial Ez component magnetic field data in real time, storing and transmitting them to the ground through digital conversion; The data fusion processing module is set up in the ground server and is used to fuse the transient electromagnetic data at different observation positions on the ground, in the roadway, and in the borehole, combine the high-resolution near-field data with the low-resolution far-field data, solve the blind area problem of single-space observation, construct a multi-scale grid model, improve the longitudinal resolution of deep target bodies, and fuse multi-period observation data in real time during the mining process to analyze the temporal variation of electrical parameters.

2. A logging-while-drilling transient electromagnetic far-detection system excited by a surface electrical source according to claim 1, wherein The three-component magnetic sensor is installed in the three-component magnetic sensor bin (2), and the three-component magnetic sensor bin (2) is fixed to the bit integrated housing (4) through a dynamic stabilization system.

3. A downhole transient electromagnetic far-detection system excited by a surface electrical source according to claim 2, characterized in that, The bit integrated housing (4) is a titanium alloy forged bit integrated housing with hard alloy cutting teeth at the front end.

4. A logging-while-drilling transient electromagnetic far-detection system excited by a surface electrical source according to claim 2, wherein The dynamic stabilization system uses a cross-axis structure and a piezoelectric actuator to achieve the dynamic stabilization of the three-component magnetic sensor bin (2). The IMU inertial measurement unit is integrated at the bottom of the three-component magnetic sensor bin (2), and static calibration is carried out by the six-position method, which can control the sensor swing when the bit orientation changes to ensure the spatial consistency of the measurement data.

5. The usage method of a downhole transient electromagnetic far-detection system excited by a surface electrical source according to any one of claims 1-4, characterized in that Specifically, it includes the following steps: (1) According to the geological structure conditions, surface undulation conditions, human facilities conditions, and high-voltage line layout conditions in the target detection area, design the emission source and borehole positions, and design the downhole and ground survey lines and grids; (2) The emission source sets the emission frequency, emission current, and emission voltage according to the target detection area; (3) A node-type transient electromagnetic instrument is set up at each measurement point of the downhole and ground survey grids, and the instrument is started to receive three-component magnetic field signals in real time and transmit them to the ground server; (5) The bit starts to drill along the designed borehole, and at the same time, the built-in receiving system in the bit starts to work, receiving three-component magnetic field data in real time and transmitting them to the ground server; (6) The data fusion processing module is set up in the ground server. First, the transient decay curves of repeated observations are weighted and superimposed to suppress random noise, automatically eliminate industrial interference, and improve the signal-to-noise ratio. Secondly, static correction is carried out to eliminate the influence of surface undulation based on the terrain DEM data; (7) Fuse the transient electromagnetic data at different observation positions on the ground, in the roadway, and in the borehole, explore the distribution of Ordovician limestone aquifers and hidden water-conducting structures before mining, and verify the integrity of the grouting curtain after the floor grouting reinforcement project; (8) During the mining process, fuse multi-period observation data in real time, analyze the temporal variation of electrical parameters, and obtain the development status of the water-conducting fissure zone in the mining disturbance area.

6. The method for using a downhole transient electromagnetic far detection system excited by a surface electrical source as claimed in claim 5, wherein When designing the position of the emission source in step (1), the angle between the direction of the emission source and the main formation structure direction is greater than 45 degrees to maximize the penetration efficiency of the excitation field to the target body.

7. The method of using a downhole transient electromagnetic far detection system excited by a surface electrical source as claimed in claim 5, wherein In step (2), the emission source uses a grounded long wire source. The emission source is arranged on the ground surface. The emission uses a 30kW inverter power supply. With a trapezoidal wave as the fundamental wave, it outputs a transient pulse with a voltage less than or equal to 1000V and a current less than or equal to 50A. It has a built-in air-cooled heat dissipation system. The emission frequency adopts an adjustable mode. The length of the emission source is 1000 - 2000 meters. The grounded long wire emits a primary step electromagnetic field underground, and the underground medium generates a secondary induced eddy current field after the excitation source is turned off.

8. The usage method of a logging-while-drilling transient electromagnetic far-detection system excited by a surface electrical source as claimed in claim 7, characterized in that, The cable of the grounded long wire uses a stranded tinned copper core cable with a cross-sectional area greater than 50mm 2 , covered with a double-layer insulation sheath and connected in sections.

9. For the usage method of a downhole transient electromagnetic remote detection system based on ground electrical source excitation as claimed in claim 7, the grounding electrode of the emission source uses a large-area conductive aluminum plate of 2m×2m, with a thickness of 5mm, galvanized on the surface for corrosion prevention, and the buried depth is greater than 3 meters.

10. The method for using a logging-while-drilling transient electromagnetic far detection system excited by a surface electrical source as claimed in claim 5, characterized in that, When designing the emission source in step (1), in a terrain undulation area with a height difference greater than 10m, the geodetic coordinates and elevation of the emission source at this point are obtained every 50 meters using a high-precision RTK instrument, and the height difference correction of the emission source is carried out during the data processing.

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