Near-bit while-drilling apparatus

Abstract

This invention relates to a near-bit logging-while-drilling (LWD) device. The upper end of the LWD instrument is connected to the drill pipe. A coaxial transmitting section is fixedly installed between the drill bit and the screw drill string, and a coaxial receiving section is fixedly installed between the LWD instrument and the screw drill string. Both the transmitting and receiving sections can switch between transmitting and receiving signals. A first communicator is installed on the receiving section, and a second communicator is installed on the transmitting section. The receiving section communicates with both the LWD instrument and the second communicator via the first communicator, and the transmitting section communicates with both the LWD instrument and the first communicator via the second communicator. This invention improves the efficiency of near-bit wireless short-transmission.

Description

Technical Field

[0001] This invention belongs to the field of geological exploration technology, and in particular relates to a near-bit drilling device. Background Technology

[0002] As oilfield development enters its later stages, the oil layers become increasingly thinner, making the process more challenging. To maintain a high oil layer encounter rate in thin oil layers, it is essential to employ near-bit drilling equipment to provide the geosteering system with wellbore orientation data and geological parameters for wellbore solidification, ensuring that the drilling trajectory meets engineering design requirements.

[0003] In the prior art, the near-bit logging-while-drilling device includes a logging-while-drilling instrument, a screw drill string, and a drill bit arranged coaxially from top to bottom. The upper end of the logging-while-drilling instrument is connected to the drill pipe. A coaxial transmitting sub is fixedly installed between the drill bit and the screw drill string, and a coaxial receiving sub is fixedly installed between the logging-while-drilling instrument and the screw drill string. The transmitting sub transmits signals, the receiving sub receives signals, processes the signals, and transmits them to the logging-while-drilling instrument. The logging-while-drilling instrument then transmits the received signals to the surface pressure sensing unit.

[0004] In the process of developing this invention, the applicant discovered that the prior art has at least the following shortcomings:

[0005] In near-bit logging-while-drilling (LTD) instruments, the transmitting sub is positioned between the drill bit and the screw drill string, while the receiving sub is positioned between the logging-while-drilling (LWD) instrument and the screw drill string. Since the screw drill string cannot be wired, signal transmission between the transmitting and receiving subs can only be achieved through wireless transmission via mud communication. The signal transmitted by the transmitting sub is then transmitted over the screw drill string to the receiving sub, which in turn transmits the signal to the LWD instrument via mud communication or other means. This results in low signal transmission efficiency. Summary of the Invention

[0006] To address the shortcomings of the existing technology, this invention provides a near-bit drilling device to solve the technical problem of low signal transmission efficiency during the use of the near-bit drilling device.

[0007] The technical solution of this invention is as follows:

[0008] A near-bit logging-while-drilling (LPD) device includes a logging-while-drilling instrument, a screw drill string, and a drill bit arranged coaxially from top to bottom. The upper end of the logging-while-drilling instrument is connected to the drill pipe. A coaxial transmitting section is fixedly arranged between the drill bit and the screw drill string. A coaxial receiving section is fixedly arranged between the logging-while-drilling instrument and the screw drill string. The characteristic feature is that both the transmitting section and the receiving section can switch between transmitting and receiving signals.

[0009] The device further includes a first communicator and a second communicator. The first communicator is disposed on the receiving sub-section, and the second communicator is disposed on the transmitting sub-section. The receiving sub-section communicates with the logging-while-drilling instrument and the second communicator through the first communicator, and the transmitting sub-section communicates with the logging-while-drilling instrument and the first communicator through the second communicator.

[0010] Furthermore, a first annular magnet with a first spiral coil wound around it is provided on the outer wall of the receiving section, and the first spiral coil is the first communicator;

[0011] The receiving section includes a receiving electronic compartment, which contains a first receiving-transmitting control module and a first single-pole double-throw relay. The first receiving-transmitting control module has a transmitting output terminal, a receiving input terminal, and a control terminal. The first single-pole double-throw relay has a stationary contact, a first moving contact, a second moving contact, and a control terminal, wherein:

[0012] The stationary contact of the first single-pole double-throw relay is connected to one end of the first spiral coil, and the other end of the first spiral coil is grounded. The first moving contact of the first single-pole double-throw relay is connected to the transmit output terminal of the first receive-transmit control module. The second moving contact of the first single-pole double-throw relay is connected to the receive input terminal of the first receive-transmit control module. The control terminal of the first single-pole double-throw relay is connected to the control terminal of the first receive-transmit control module.

[0013] Furthermore, the first receiving and transmitting control module includes a first controller, a first encoding transmitting circuit, a first decoding receiving circuit, and a first energy storage battery, wherein:

[0014] The first controller is connected to the input terminal of the first encoding transmission circuit, the output terminal of the first decoding reception circuit, and the control terminal of the first single-pole double-throw relay. The output terminal of the first encoding transmission circuit is the transmission output terminal of the first receiving transmission control module, and the input terminal of the first decoding reception circuit is the receiving input terminal of the first receiving transmission control module. The first energy storage battery powers the first controller.

[0015] Furthermore, a first annular groove is provided on the outer wall of the receiving section, the first annular magnet is disposed in the first annular groove, and a first cover plate is provided outside the first annular groove.

[0016] Furthermore, the outer wall of the transmitting sub is provided with a second annular magnet wound with a second helical coil, the second helical coil being the second communicator;

[0017] The transmitting section includes a transmitting electronics compartment, which contains a second receiving and transmitting control module and a second single-pole double-throw relay. The second receiving and transmitting control module has a transmitting output terminal, a receiving input terminal, and a control terminal. The second single-pole double-throw relay has a stationary contact, a first moving contact, a second moving contact, and a control terminal.

[0018] The stationary contact of the second single-pole double-throw relay is connected to one end of the second spiral coil, and the other end of the second spiral coil is grounded. The first moving contact of the second single-pole double-throw relay is connected to the transmit output terminal of the second receive-transmit control module. The second moving contact of the second single-pole double-throw relay is connected to the receive input terminal of the second receive-transmit control module. The control terminal of the second single-pole double-throw relay is connected to the control terminal of the second receive-transmit control module.

[0019] Furthermore, the second receive-transmit control module includes a second controller, a second encoding transmit circuit, a second decoding receive circuit, and a second energy storage battery, wherein:

[0020] The second controller is connected to the input terminal of the second encoding transmission circuit, the output terminal of the second decoding reception circuit, and the control terminal of the second single-pole double-throw relay, respectively; the output terminal of the second encoding transmission circuit is the transmission output terminal of the second receiving transmission control module; the input terminal of the second decoding reception circuit is the receiving input terminal of the second receiving transmission control module; the second energy storage battery powers the second controller.

[0021] Furthermore, a second annular groove is provided on the outer wall of the launching section, the second annular magnet is disposed in the second annular groove, and a second cover plate is provided outside the second annular groove.

[0022] Furthermore, both the first communicator and the second communicator include:

[0023] A connecting post, wherein the first annular magnet of the first communicator and the second annular magnet of the second communicator are wound around the outer peripheral surface of the corresponding connecting post;

[0024] An insulating layer is wrapped around the outside of the first annular magnet of the first communicator and the second annular magnet of the second communicator.

[0025] An anti-wear cage is provided outside the insulating layer, and epoxy colloid is filled between the anti-wear cage and the insulating layer.

[0026] Furthermore, the outer circumferential surface of the connecting post is provided with multiple notches, and the multiple notches are arranged at equal angles around the circumferential surface of the connecting post. The first annular magnet of the first communicator and the second annular magnet of the second communicator are respectively filled with insulating colloid between the notches.

[0027] Furthermore, the insulating layer includes enameled wire and fiberglass cloth. The enameled wire is wrapped around the outside of the first annular magnet of the first communicator and the second annular magnet of the second communicator. The fiberglass cloth is wrapped around the outside of the enameled wire and is disposed between the enameled wire and the epoxy colloid.

[0028] The beneficial effects of this invention are:

[0029] The near-bit logging-while-drilling device provided by this invention enables remote debugging of the transmitting sub, wireless short-passing between the transmitting and receiving subs, and wireless short-passing between the receiving sub and the logging-while-drilling instrument, thus improving the efficiency of near-bit wireless short-passing. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a schematic diagram of a near-bit drilling device according to this embodiment;

[0032] Figure 2 for Figure 1 A schematic diagram of the receiving section in the middle;

[0033] Figure 3 for Figure 2 A schematic diagram of the component control within the receiving electronic compartment;

[0034] Figure 4 for Figure 1 A schematic diagram of the launch section in the middle;

[0035] Figure 5 for Figure 4 A schematic diagram of the component control within the launch electronics compartment;

[0036] Figure 6 This is a schematic diagram of the communicator in this embodiment. Detailed Implementation

[0037] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] Figure 1 This is a schematic diagram of a near-bit drilling device according to this embodiment, combined with... Figure 1 The device includes a logging-while-drilling instrument 1, a screw drill string 3, and a drill bit 2 arranged coaxially from top to bottom. The upper end of the logging-while-drilling instrument 1 is connected to the drill pipe 4. A coaxial transmitting section 5 is fixedly arranged between the drill bit 2 and the screw drill string 3. A coaxial receiving section 6 is fixedly arranged between the logging-while-drilling instrument 1 and the screw drill string 3. In this embodiment, both the transmitting section 5 and the receiving section 6 can switch between transmitting or receiving signals.

[0039] Combination Figure 1 The device in this embodiment also includes a first communicator and a second communicator. The first communicator is disposed on the receiving sub-section 6, and the second communicator is disposed on the transmitting sub-section 5. The receiving sub-section 6 communicates with the logging-while-drilling instrument 1 and the second communicator through the first communicator, and the transmitting sub-section 5 communicates with the logging-while-drilling instrument 1 and the first communicator through the second communicator.

[0040] Figure 2 for Figure 1 The structural diagram of the receiving section in the diagram, combined with Figure 2 In this embodiment, a first annular magnet 7 with a first spiral coil wound around it is provided on the outer wall of the receiving section 6. The first spiral coil is the aforementioned first communicator.

[0041] Furthermore, combined Figure 2 In this embodiment, a first annular groove is provided on the outer wall of the receiving section 6, and a first annular magnet 7 with a first spiral coil wound around it is disposed in the first annular groove. A first cover plate 8 is provided outside the first annular groove to prevent external mud from entering the first annular groove and affecting the normal operation of the first annular magnet 7.

[0042] Furthermore, combined Figure 2 In this embodiment, the receiving section 6 is equipped with a receiving electronic compartment 9. Figure 3 for Figure 2 The schematic diagram of the component control inside the receiving electronic compartment, combined with Figure 2 as well as Figure 3In this embodiment, the receiving electronic compartment 9 is provided with a first receiving and transmitting control module 10 and a first single-pole double-throw relay 11. The first receiving and transmitting control module 10 has a transmitting output terminal, a receiving input terminal, and a control terminal. The first single-pole double-throw relay 11 has a stationary contact, a first moving contact, a second moving contact, and a control terminal. The stationary contact of the first single-pole double-throw relay 11 is connected to one end of the first spiral coil 12, and the other end of the first spiral coil 12 is grounded. The first moving contact of the first single-pole double-throw relay 11 is connected to the transmitting output terminal of the first receiving and transmitting control module 10. The second moving contact of the first single-pole double-throw relay 11 is connected to the receiving input terminal of the first receiving and transmitting control module 10. The control terminal of the first single-pole double-throw relay 11 is connected to the control terminal of the first receiving and transmitting control module 10.

[0043] Therefore, when the first single-pole double-throw relay 11 closes its first moving contact, the first receive-transmit control module 10 switches to transmit mode, and the first spiral coil of the first ring magnet 7 becomes the transmitting antenna. When the first single-pole double-throw relay 10 closes its second moving contact, the first receive-transmit control module 10 switches to receive mode, and the first spiral coil of the first ring magnet 7 becomes the receiving antenna.

[0044] The first receiving and transmitting control module 10 is a module with information encoding and transmitting functions and information decoding and receiving functions. Here is a preferred example:

[0045] The first receiving and transmitting control module 10 includes a first controller, a first encoding transmitting circuit, a first decoding receiving circuit, and a first energy storage battery. The first controller is connected to the input terminal of the first encoding transmitting circuit, the output terminal of the first decoding receiving circuit, and the control terminal of the first single-pole double-throw relay. The output terminal of the first encoding transmitting circuit is the transmitting output terminal of the first receiving and transmitting control module, and the input terminal of the first decoding receiving circuit is the receiving input terminal of the first receiving and transmitting control module. The first energy storage battery powers the first controller.

[0046] In addition, the first encoding transmitting circuit includes a first encoder, a first carrier modulation circuit, and a first multivibrator connected in series; the first decoding receiving circuit includes a first preamplifier circuit, a first filter circuit, a first programmable amplifier circuit, and a first decoder connected in series. The first encoder can be an HT-12E digital encoding chip, and the first decoder can be an HT-12D digital decoding chip.

[0047] Figure 4 for Figure 1 A schematic diagram of the launch section in the middle, combined with Figure 4 In this embodiment, the outer wall of the transmitting section 5 is provided with a second annular magnet 13 with a second spiral coil wound around it, and the second spiral coil is the aforementioned second communicator.

[0048] Furthermore, combined Figure 4 In this embodiment, a second annular groove is provided on the outer wall of the launching section 5, and a second annular magnet 13 with a second spiral coil wound around it is disposed in the second annular groove. A second cover plate 14 is provided outside the second annular groove to prevent external mud from entering the second annular groove and affecting the normal operation of the second annular magnet 13.

[0049] Combination Figure 4 In this embodiment, the launch section 5 is equipped with a launch electronics compartment 15. Figure 5 for Figure 4 A schematic diagram of the component control inside the launch electronics compartment, combined with... Figure 4 as well as Figure 5 In this embodiment, the transmitting electronic compartment 15 is provided with a second receiving and transmitting control module 16 and a second single-pole double-throw relay 17. The second receiving and transmitting control module 16 has a transmitting output terminal, a receiving input terminal, and a control terminal. The second single-pole double-throw relay 17 has a stationary contact, a first moving contact, a second moving contact, and a control terminal. The stationary contact of the second single-pole double-throw relay 17 is connected to one end of the second spiral coil 26, and the other end of the second spiral coil 26 is grounded. The first moving contact of the second single-pole double-throw relay 17 is connected to the transmitting output terminal of the second receiving and transmitting control module 16. The second moving contact of the second single-pole double-throw relay 17 is connected to the receiving input terminal of the second receiving and transmitting control module 16. The control terminal of the second single-pole double-throw relay 17 is connected to the control terminal of the second receiving and transmitting control module 16.

[0050] Therefore, when the second single-pole double-throw relay 17 closes its first moving contact, the second receive-transmit control module 16 switches to transmit mode, and the second spiral coil becomes the transmitting antenna; when the second single-pole double-throw relay 17 closes its second moving contact, the second receive-transmit control module 16 switches to receive mode, and the second spiral coil becomes the receiving antenna.

[0051] Similarly, the second receiving and transmitting control module 16 in this embodiment is a module with information encoding and transmitting functions and information decoding and receiving functions. Here is a preferred example:

[0052] The second receive-transmit control module 16 includes a second controller, a second encoding transmit circuit, a second decoding receive circuit, and a second energy storage battery. The second controller is connected to the input terminal of the second encoding transmit circuit, the output terminal of the second decoding receive circuit, and the control terminal of the second single-pole double-throw relay. The output terminal of the second encoding transmit circuit is the transmit output terminal of the second receive-transmit control module. The input terminal of the second decoding receive circuit is the receive input terminal of the second receive-transmit control module. The second energy storage battery powers and is connected to the second controller.

[0053] Here, the second encoding transmitting circuit includes a second encoder, a second carrier modulation circuit, and a second multivibrator connected in series; the second decoding receiving circuit includes a second preamplifier circuit, a second filter circuit, a second programmable amplifier circuit, and a second decoder connected in series. The second encoder can be an HT-12E digital encoding chip, and the second decoder can be an HT-12D digital decoding chip.

[0054] The working principle of the near-bit drilling device in this embodiment is as follows:

[0055] When performing remote debugging of the transmitter sub, the first helical coil is converted into a transmitting coil, and the second helical coil is converted into a receiving coil. This enables the first receiving and transmitting control module to send an encoded debugging command through the first helical coil. The encoded debugging command is modulated into a high-frequency signal, which causes eddy currents to be generated between the receiving sub and the ground in various directions. These eddy currents generate an alternating electromagnetic field around the second helical coil, thereby generating an induced current related to the encoded debugging command. The second receiving and transmitting control module obtains the debugging command by decoding the encoded debugging command carried by the induced current, thus realizing the remote debugging function of the transmitter sub.

[0056] When performing wireless short-transmission between the transmitting and receiving sub-subs, the first helical coil is converted into a receiving coil, and the second helical coil is converted into a transmitting coil. This enables the second receiving and transmitting control module to transmit encoded downhole measurement data (such as well inclination azimuth, tool face angle, formation resistivity, and natural gamma value) through the second helical coil. This encoded downhole measurement data is modulated into a high-frequency signal, which causes eddy currents to be generated between the transmitting sub-sub and the formation in various directions. These eddy currents generate an alternating electromagnetic field around the first helical coil, thereby generating an induced current related to the encoded downhole measurement data. The first receiving and transmitting control module obtains the downhole measurement data by decoding the encoded downhole measurement data carried by the induced current, thus realizing the wireless short-transmission function between the transmitting and receiving sub-subs.

[0057] When performing wireless short-transmission between the receiving sub and the logging-while-drilling (LWD) instrument, the first helical coil is converted into a transmitting coil, enabling the first receiving and transmitting control module to transmit encoded transmission data through the first helical coil. This encoded transmission data is modulated into a high-frequency signal, causing eddy currents to be generated between the receiving sub and the formation in various directions. These eddy currents generate an alternating electromagnetic field around the LWD instrument, causing the LWD instrument to receive an induced current related to the encoded transmission data. The LWD instrument obtains the transmission data by decoding the encoded transmission data carried by the induced current, thereby realizing the wireless short-transmission function between the receiving sub and the LWD instrument.

[0058] This embodiment is equipped with a transmit and receive control module on both the transmit and receive subs, enabling both the transmit and receive subs to receive and transmit signals. This achieves remote debugging of the transmit subs, wireless short-pass functionality between the transmit and receive subs, and wireless short-pass functionality between the receive subs and logging-while-drilling instruments, thereby improving the efficiency of near-bit wireless short-pass functionality.

[0059] In this embodiment, the first communicator and the second communicator are key components responsible for transmitting signal commands. In order to ensure the reliability of the communicators during use, the structure of the communicators is improved in this embodiment.

[0060] Figure 6 This is a schematic diagram of the communicator in this embodiment, combined with... Figure 6 The communicator in this embodiment includes a connecting post 18, a magnet 19 with a spiral coil wound around it, an insulating layer, an anti-wear cage 20, and an epoxy colloid 21.

[0061] Combination Figure 6 In this embodiment, the connecting post 18 serves as the carrier of the antenna, which is preferably a non-magnetic drill collar. The non-magnetic drill collar is a low-carbon, high-chromium-manganese alloy steel drill collar that is refined through strict chemical composition ratio. It has good low magnetic permeability and high mechanical strength, which can reduce the impact on communication.

[0062] Combination Figure 6 In this embodiment, the connecting post 18 has a through hole so that it can be fitted into the corresponding groove.

[0063] Referring to Figure 6, in this embodiment, the magnet 19 is wound around the outer peripheral surface of the connecting post 18 to realize the communication function of near-drill bit signal.

[0064] Furthermore, combined Figure 6 In this embodiment, the outer peripheral surface of the connecting post 18 is provided with a plurality of notches 22, which are arranged at equal angles around the peripheral surface of the connecting post 18. The space between the magnet 19 and the notches 22 is filled with insulating colloid 23, which can further improve the insulation effect between the magnet 19 and the connecting post 18. In addition, this allows the magnet 19 to have a first friction surface that contacts the connecting post 18 and a second friction surface that contacts the insulating colloid 23. The first friction surface and the second friction surface have different degrees of friction, thereby improving the firmness of the magnet 19 in the assembly on the connecting post 18.

[0065] Preferably, the insulating colloid 23 in this embodiment can be made of epoxy resin.

[0066] In this embodiment, the notch 22 is preferably a plane, which is parallel to the central axis of the connecting post 18.

[0067] Combination Figure 6In this embodiment, the insulating layer is wrapped around the outside of the magnet 19 to achieve the insulation of the antenna from the outside world.

[0068] Combination Figure 6 In this embodiment, the insulating layer includes enameled wire 24, which is wrapped around the outside of magnet 19.

[0069] Furthermore, combined Figure 6 In this embodiment, the insulating layer also includes fiberglass cloth 25, which wraps around the outside of the enameled wire 24 and is disposed between the enameled wire and the epoxy colloid 23. The fiberglass cloth 25 has a certain degree of rigidity, which can resist external interference and prevent the magnet 19 from deforming, thus ensuring normal communication.

[0070] Combination Figure 6 In this embodiment, the anti-wear cage 20 is covered outside the insulating layer, and epoxy colloid 21 is filled between the anti-wear cage 20 and the insulating layer (fiberglass cloth 25).

[0071] Preferably, the anti-wear cage 20 in this embodiment is made of metal, such as corrosion-resistant stainless steel, but this embodiment does not limit the material.

[0072] During the use of the near-bit drilling instrument, the anti-abrasion cage of this embodiment can prevent the insulation layer from being damaged due to friction, thus affecting the insulation effect of the antenna. Furthermore, since the anti-abrasion cage and the insulation layer are filled with epoxy colloid, not only can the connection between the anti-abrasion cage and the insulation layer be achieved, but it can also prevent underground mud from entering the insulation layer and the magnet, thus affecting the insulation effect of the antenna and the communication operation of the magnetic strip. It has good practicality.

[0073] The following embodiments are preferred embodiments of the present invention and are only used to facilitate the illustration of the present invention. They are not intended to limit the present invention in any way. Any person skilled in the art who makes local modifications or alterations to the technical content disclosed in the present invention without departing from the scope of the technical features of the present invention shall still fall within the scope of the technical features of the present invention.

Claims

1. A near-bit drilling-while-drilling device, the device comprising, from top to bottom, a logging-while-drilling instrument, a screw drill and a drill bit, the upper end of the logging-while-drilling instrument being connected with a drill pipe, a coaxial transmitting sub being fixedly arranged between the drill bit and the screw drill, and a coaxial receiving sub being fixedly arranged between the logging-while-drilling instrument and the screw drill, characterized in that, The transmitting short section and the receiving short section can switch to transmit or receive signals; The device further comprises a first communication device and a second communication device, the first communication device is arranged on the receiving short section, the second communication device is arranged on the transmitting short section, the receiving short section communicates with the logging-while-drilling instrument and the second communication device through the first communication device respectively, and the transmitting short section communicates with the logging-while-drilling instrument and the first communication device through the second communication device respectively; The outer wall of the receiving short section is provided with a first annular magnet with a first spiral coil wound thereon, and the first spiral coil is an antenna of the first communication device; The receiving short section is provided with a receiving electronic bin, the receiving electronic bin is provided with a first receiving and transmitting control module and a first single-pole double-throw relay, the first receiving and transmitting control module has a transmitting output end, a receiving input end and a control end, and the first single-pole double-throw relay has a static contact, a first dynamic contact, a second dynamic contact and a control end, wherein: One end of the first spiral coil is connected with the static contact of the first single-pole double-throw relay, the other end of the first spiral coil is grounded, the first dynamic contact of the first single-pole double-throw relay is connected with the transmitting output end of the first receiving and transmitting control module, the second dynamic contact of the first single-pole double-throw relay is connected with the receiving input end of the first receiving and transmitting control module, and the control end of the first single-pole double-throw relay is connected with the control end of the first receiving and transmitting control module; The outer wall of the transmitting short section is provided with a second annular magnet with a second spiral coil wound thereon, and the second spiral coil is an antenna of the second communication device; The transmitting short section is provided with a transmitting electronic bin, the transmitting electronic bin is provided with a second receiving and transmitting control module and a second single-pole double-throw relay, the second receiving and transmitting control module has a transmitting output end, a receiving input end and a control end, and the second single-pole double-throw relay has a static contact, a first dynamic contact, a second dynamic contact and a control end, wherein: One end of the second spiral coil is connected with the static contact of the second single-pole double-throw relay, the other end of the second spiral coil is grounded, the first dynamic contact of the second single-pole double-throw relay is connected with the transmitting output end of the second receiving and transmitting control module, the second dynamic contact of the second single-pole double-throw relay is connected with the receiving input end of the second receiving and transmitting control module, and the control end of the second single-pole double-throw relay is connected with the control end of the second receiving and transmitting control module; The first communication device and the second communication device each comprise: A connecting column, the first annular magnet of the first communication device and the second annular magnet of the second communication device are wound on the outer circumferential surface of the corresponding connecting column; An insulating layer, the insulating layer is wrapped on the outside of the corresponding first annular magnet of the first communication device and the second annular magnet of the second communication device; An anti-abrasion cage, the anti-abrasion cage is arranged outside the insulating layer, and the anti-abrasion cage and the insulating layer are filled with an epoxy glue. The outer circumferential surface of the connecting column is provided with a plurality of notches, the plurality of notches are provided equiangularly around the circumferential surface of the connecting column, and the first annular magnet of the first communication device and the second annular magnet of the second communication device are filled with insulating glue between the corresponding notches; The first annular magnet and the second annular magnet both have a first friction surface in contact with the connecting column and a second friction surface in contact with the insulating glue, and the first friction surface and the second friction surface have different degrees of friction.

2. The near-bit while-drilling device of claim 1, wherein, The first receiving and transmitting control module comprises a first controller, a first encoding transmitting circuit, a first decoding receiving circuit and a first energy storage battery, wherein: The first controller is connected to the input end of the first encoding transmitting circuit, the output end of the first decoding receiving circuit and the control end of the first single-pole double-throw relay respectively, the output end of the first encoding transmitting circuit is the transmitting output end of the first receiving and transmitting control module, the input end of the first decoding receiving circuit is the receiving input end of the first receiving and transmitting control module, and the first energy storage battery is connected to the first controller for power supply.

3. The near-bit while-drilling device of claim 1, wherein, The outer wall of the receiving short section is provided with a first annular groove, the first annular magnet is arranged in the first annular groove, and the first annular groove is externally provided with a first cover plate.

4. The near-bit while-drilling device of claim 1, wherein, The second receiving and transmitting control module comprises a second controller, a second encoding transmitting circuit, a second decoding receiving circuit and a second energy storage battery, wherein: The second controller is connected to the input end of the second encoding transmitting circuit, the output end of the second decoding receiving circuit and the control end of the second single-pole double-throw relay respectively; the output end of the second encoding transmitting circuit is the transmitting output end of the second receiving and transmitting control module; the input end of the second decoding receiving circuit is the receiving input end of the second receiving and transmitting control module; and the second energy storage battery is connected to the second controller for power supply.

5. The near-bit while-drilling device of claim 1, wherein, The outer wall of the transmitting short section is provided with a second annular groove, the second annular magnet is arranged in the second annular groove, and the second annular groove is externally provided with a second cover plate.

6. The near-bit while-drilling device of claim 1, wherein, The insulating layer comprises an enameled wire and a glass steel cloth, the enameled wire is wrapped outside the first annular magnet of the first communication device and the second annular magnet of the second communication device, the glass steel cloth is wrapped outside the enameled wire, and the glass steel cloth is arranged between the enameled wire and the epoxy glue.

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