Coring tool for monitoring length of underground rock core in real time

Abstract

The coring tool comprises a shell and a drill bit installed at the lower end of the shell, a mud pulse generator and a control driving module are arranged at the upper end in the shell, a coring inner cylinder is arranged at the lower end in the shell, and a Hall element in communication connection with the control driving module is arranged on the side wall of the coring inner cylinder. An induction disc is arranged in the coring inner cylinder, a magnetic element is installed on the induction disc, a rock core enters the coring inner cylinder during coring, the induction disc is pushed to move upwards in the axial direction of the coring inner cylinder, and the Hall element detects the position of the magnetic element and sends a signal to the control driving module. The core length can be monitored in real time in the coring process, core blockage or jamming can be found in time, core abrasion is avoided, manual experience interpretation is avoided, detection is faster and more accurate, and the detection accuracy and safety are improved.

Description

Technical Field

[0001] The invention relates to the field of resource exploration, and in particular to a coring tool for real-time monitoring of downhole core length. Background Art

[0002] Well coring is a special drilling operation in oil and gas exploration and development. It is currently the only way to obtain original stratigraphic profile specimens, which can truly understand the sedimentary characteristics, lithological characteristics, oil, gas and water characteristics and other structural characteristics of underground rock formations and reservoirs. In addition, coring can fully understand the relationship between lithology and electrical properties, and provide stratigraphic basis for the reasonable interpretation of seismic and logging results.

[0003] The coring tool is a sampling tool for obtaining formation rocks. Existing coring tools for soft and broken formations are prone to blockage or jamming during the coring process. Coring engineers can only judge blockage or jamming by changes in drilling parameters such as drilling pressure and torque. However, when blockage or jamming occurs in complex formations or formation boundaries, even experienced coring engineers find it difficult to detect in time, resulting in grinding coring. At the end of coring, hydraulic or mechanical pressurization is often used to cut the core, and the core cutting can only be started after the ball is dropped. However, the back pressure valve used in the drill bit assembly in some blocks does not allow the ball to be dropped, so hydraulic or mechanical pressurization cannot be used to cut the core.

[0004] Therefore, how to provide a coring tool that can monitor the core length in real time and cut the core in a non-ball throwing manner is a technical problem that those skilled in the art need to solve at present. Summary of the invention

[0005] The purpose of the present invention is to provide a coring tool for real-time monitoring of the length of downhole cores. Through a magnetic element that moves with the core and a Hall element that detects the magnetic element, real-time monitoring of the core length can be achieved during the coring process, core blockage or sticking can be discovered in time, core grinding can be avoided, and the core can be cut electrically.

[0006] In order to solve the above technical problems, the present invention provides a coring tool for real-time monitoring of the length of downhole cores, comprising a shell and a drill bit installed at the lower end of the shell, a mud pulse generator and a control drive module are arranged at the upper end of the shell, a coring inner barrel is arranged at the lower end of the shell, a Hall element communicatively connected to the control drive module is arranged on the side wall of the coring inner barrel, an induction disk is arranged inside the coring inner barrel, and a magnetic element is installed on the induction disk. During coring, the core enters the coring inner barrel and pushes the induction disk to move upward along the axial direction of the coring inner barrel, and the Hall element detects the position of the magnetic element and sends a signal to the control drive module.

[0007] Preferably, a plurality of the Hall elements are embedded in the outer side of the side wall of the coring inner cylinder, and the plurality of the Hall elements are arranged in sequence along the axial direction of the coring inner cylinder and connected in series through lower cables, and a plurality of groups of the lower cables connected in series with the Hall elements are evenly arranged along the circumferential direction on the side wall of the coring inner cylinder.

[0008] Preferably, a core claw is installed at the lower end of the coring inner cylinder, the inner wall of the drill bit is provided with a conical surface that converges inward from top to bottom, and a power assembly is provided in the middle of the shell. The power assembly can push the coring inner cylinder to move downward along the axial direction of the shell, and the conical surface pushes the core claw to converge to cut the core.

[0009] Preferably, the power assembly includes an angular velocity sensor, a battery, a pressure compensating oil tank, an electric motor, a high-pressure pump, a multi-channel electrical connector and a piston. A working sleeve is provided at the lower end of the multi-channel electrical connector, and the upper end of the piston is inserted into the working sleeve to form a sealed cavity. The electric motor drives the high-pressure pump to operate, and the hydraulic oil in the pressure compensating oil tank is input into the sealed cavity to push the piston to move downward along the axial direction of the housing.

[0010] Preferably, a suspension mechanism is provided between the piston and the coring inner cylinder, a positioning mechanism cooperating with the suspension mechanism is provided on the inner wall of the shell, and the piston pushes the coring inner cylinder through the suspension mechanism.

[0011] Preferably, a conductive slip ring is installed below the suspension mechanism, the lower cable is connected to the conductive slip ring, the conductive slip ring is connected to the control drive module through an upper cable, and the upper cable passes through the multi-channel electrical connector.

[0012] Preferably, the piston includes a sealing section, a solid cylindrical section, a hollow conical section and a hollow cylindrical section arranged in sequence from top to bottom, a limiting shoulder is arranged on the outer side of the side wall of the hollow cylindrical section, a first piston through hole is arranged on the side wall of the hollow conical section, a second piston through hole is arranged on the side wall of the hollow cylindrical section, the sealing section extends into the working sleeve, the hollow cylindrical section extends into the suspension mechanism, and the limiting shoulder can be abutted against the upper end surface of the suspension mechanism.

[0013] Preferably, the shell includes an upper shell, a middle shell and a lower shell which are threadedly connected in sequence from top to bottom; the mud pulse generator, the control drive module, the angular velocity sensor, the battery, the pressure compensation oil tank, the motor, the high-pressure pump and the multi-channel electrical connector are located in the upper shell, the piston and the suspension mechanism are located in the middle shell, and the coring inner barrel is located in the lower shell.

[0014] Preferably, the multi-channel electrical connector includes a disc, a connecting sleeve arranged at the upper end of the disc and the working sleeve arranged at the lower end of the disc, an oil pressure hole connecting the connecting sleeve and the working sleeve is arranged at the center of the disc, a radially extending electrical hole is arranged on the side of the disc, an axially extending electrical plug-in hole is arranged on the top of the disc, the electrical hole is connected to the electrical plug-in hole, and a plurality of current holes are arranged on the disc.

[0015] Preferably, a support cylinder is provided on the outer periphery of the working sleeve, and the upper end of the support cylinder abuts against the lower edge of the disc.

[0016] The present invention provides a coring tool for real-time monitoring of downhole core length, comprising a shell and a drill bit installed at the lower end of the shell, a mud pulse generator and a control drive module are arranged at the upper end of the shell, a coring inner barrel is arranged at the lower end of the shell, a Hall element for communication connection with the control drive module is arranged on the side wall of the coring inner barrel, an induction disk is arranged inside the coring inner barrel, and a magnetic element is installed on the induction disk. During coring, the core enters the coring inner barrel and pushes the induction disk to move upward along the axial direction of the coring inner barrel, and the Hall element detects the position of the magnetic element and sends a signal to the control drive module.

[0017] During the operation, the core enters the coring inner barrel from the drill bit, and the core contacts the induction disk, pushing the induction disk upward. The magnetic element in the induction disk interacts with the Hall element on the coring inner barrel to generate a periodically changing induced electromotive force. The induced electromotive force signal is transmitted to the control drive module, which encodes the induced electromotive force and sends it to the ground through the mud pulse generator. The ground receiving module decodes the encoded pulse signal to obtain the core length. The core length can be monitored in real time during the coring process, and core blockage or jamming can be discovered in time, avoiding core grinding and manual experience interpretation. The detection is faster and more accurate, improving detection accuracy and safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A structural schematic diagram of a specific implementation of a coring tool for real-time monitoring of downhole core length provided by the present invention;

[0019] Figure 2 A partial enlarged view of the upper end of a specific implementation of a coring tool for real-time monitoring of downhole core length provided by the present invention;

[0020] Figure 3 A partial enlarged view of the middle and lower end of a specific implementation of a coring tool for real-time monitoring of downhole core length provided by the present invention;

[0021] Figure 4 for Figure 3 A partial enlarged view of point Ⅰ in the middle;

[0022] Figure 5 A schematic structural diagram of a piston in a specific implementation of a coring tool for real-time monitoring of downhole core length provided by the present invention;

[0023] Figure 6 A schematic structural diagram of a multi-channel electrical connector in a specific implementation of a coring tool for real-time monitoring of downhole core length provided by the present invention;

[0024] Figure 7 for Figure 6 Middle AA section view;

[0025] Figure 8 Bit Figure 6 Schematic diagram of direction B.

[0026] Among them, 1. Mud pulse generator; 2. Control drive module; 3. Angular velocity sensor; 4. Battery; 5. Upper shell; 6. Pressure compensation oil tank; 7. Motor; 8. High-pressure pump; 9. Multi-channel electrical connector; 901. Connecting sleeve; 902. Disc; 903. Working sleeve; 904. Oil pressure hole; 905. Electrical hole; 906. Flow hole; 907. Electrical plug hole; 10. Piston; 101. Sealing section; 102. Solid cylindrical section; 103. Air Core cone section; 104, first piston through hole; 105, limit shoulder; 106, second piston through hole; 107, hollow cylindrical section; 11, support tube; 12, middle shell; 13, positioning mechanism; 14, suspension mechanism; 15, conductive slip ring; 16, lower cable; 17, Hall element; 18, lower shell; 19, coring inner tube; 20, magnetic element; 21, induction disk; 22, drill bit; 23, core claw; 24, sealing cavity; 211, induction through hole. DETAILED DESCRIPTION

[0027] The core of the present invention is to provide a coring tool for real-time monitoring of the length of downhole cores. Through a magnetic element that moves with the core and a Hall element that detects the magnetic element, real-time monitoring of the core length can be achieved during the coring process, and core blockage or sticking can be discovered in time to avoid core grinding.

[0028] In order to enable those skilled in the art to better understand the scheme of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0029] Please refer to Figures 1 to 4 , Figure 1 A structural schematic diagram of a specific implementation of a coring tool for real-time monitoring of downhole core length provided by the present invention; Figure 2 A partial enlarged view of the upper end of a specific implementation of a coring tool for real-time monitoring of downhole core length provided by the present invention; Figure 3A partial enlarged view of the middle and lower end of a specific implementation of a coring tool for real-time monitoring of downhole core length provided by the present invention; Figure 4 for Figure 3 A partial enlarged view of point Ⅰ in the middle.

[0030] The specific embodiment of the present invention provides a coring tool for real-time monitoring of the length of downhole cores, including a shell and a drill bit 22 installed at the lower end of the shell, a mud pulse generator 1 and a control drive module 2 are arranged at the upper end of the shell, a coring inner cylinder 19 is arranged at the lower end of the shell, a Hall element 17 for communication connection with the control drive module 2 is arranged on the side wall of the coring inner cylinder 19, an induction disc 21 is arranged inside the coring inner cylinder 19, and a magnetic element 20 is installed on the induction disc 21. When coring, the core enters the coring inner cylinder 19 and pushes the induction disc 21 to move upward along the axial direction of the coring inner cylinder 19. The Hall element 17 detects the position of the magnetic element 20 and sends a signal to the control drive module 2. Specifically, a mounting groove is arranged at the center of the upper surface of the induction disc 21, and the magnetic element 20 is embedded in the mounting groove. A plurality of induction through holes 211 are arranged around the mounting groove position on the induction disc 21.

[0031] During the operation, the core enters the coring inner tube 19 through the drill bit 22, and the core contacts the induction disk 21, pushing the induction disk 21 upward. The magnetic element 20 in the induction disk 21 interacts with the Hall element 17 on the coring inner tube 19 to generate a periodically changing induced electromotive force. The induced electromotive force signal is transmitted to the control drive module 2, and the control drive module 2 encodes the induced electromotive force and sends it to the ground through the mud pulse generator 1. The ground receiving module decodes the encoded pulse signal to obtain the core length. The core length can be monitored in real time during the coring process, and core blockage or stuck core can be found in time, core grinding can be avoided, and manual experience judgment can be avoided. The detection is faster and more accurate, and the detection accuracy and safety are improved.

[0032] In order to ensure the accuracy of detection, multiple Hall elements 17 can be set. At the same time, due to the characteristics of the Hall elements 17, they do not need to be in direct contact with the magnetic element 20. In order to avoid damage, multiple Hall elements 17 are embedded in the outer side of the side wall of the core inner cylinder 19. Further, multiple Hall elements 17 are arranged in sequence along the axial direction of the core inner cylinder 19 and connected in series through the lower cable 16. The Hall elements 17 on a lower cable 16 are a group. Multiple groups of Hall elements 17 can be set, that is, multiple groups of lower cables 16 with multiple groups of Hall elements 17 in series are evenly arranged along the circumferential direction on the side wall of the core inner cylinder 19. The number and layout of the Hall elements 17 can be adjusted according to the situation, which is within the protection scope of the present invention. .

[0033] In the coring tool for real-time monitoring of downhole core length provided in the specific embodiment of the present invention, in order to complete the core cutting action, a core claw 23 is installed at the lower end of the coring inner cylinder 19, and the core claw 23 and the drill bit 22 are both cylindrical structures with upper and lower openings. At the same time, the inner wall of the drill bit 22 is provided with a conical surface that converges inward from top to bottom, and a power component is provided in the middle of the shell. When core cutting is required, the power component can push the coring inner cylinder 19 to move downward along the axial direction of the shell, that is, the core claw 23 at the lower end of the coring inner cylinder 19 and the drill bit 22 undergo axial relative movement, and the conical surface in the drill bit 22 pushes the core claw 23, and the core claw 23 deforms and contracts, shrinking inward to cut the core.

[0034] Specifically, the power assembly is hydraulically driven, including an angular velocity sensor 3, a battery 4, a pressure compensation tank 6, an electric motor 7, a high-pressure pump 8, a multi-channel electrical connector 9 and a piston 10, wherein the multi-channel electrical connector 9 has a cylinder structure, and cooperates with the piston 10 to form a hydraulic cylinder structure, and a working sleeve 903 is provided at the lower end of the multi-channel electrical connector 9, and the upper end of the piston 10 is inserted into the working sleeve 903 to form a sealed cavity 24. When the heart needs to be cut, the electric motor 7 drives the high-pressure pump 8 to work, and the hydraulic oil in the pressure compensation tank 6 is input into the sealed cavity 24 to push the piston 10 to move downward along the axial direction of the shell.

[0035] Furthermore, a suspension mechanism 14 is provided between the piston 10 and the coring inner cylinder 19, and a positioning mechanism 13 cooperating with the suspension mechanism 14 is provided on the inner wall of the housing, and the piston 10 pushes the coring inner cylinder 19 through the suspension mechanism 14. During normal operation, the suspension mechanism 14 is fixed in a normal position by the positioning mechanism 13, and when cutting the core, the piston 10 moves downward to trigger the positioning mechanism 13 to unlock, and then the suspension structure 14 can move and is pushed downward by the piston 10.

[0036] In order to achieve communication connection, a conductive slip ring 15 is installed under the suspension mechanism 14, and the lower cable 16 is connected to the conductive slip ring 15. The conductive slip ring 15 is connected to the control drive module 2 through the upper cable, and the upper cable passes through the multi-channel electrical connector 9.

[0037] Please refer to Figure 5 , Figure 5 A schematic structural diagram of a piston in a specific implementation manner of a coring tool for real-time monitoring of downhole core length provided by the present invention.

[0038] In the coring tool for real-time monitoring of downhole core length provided by the specific embodiment of the present invention, the piston 10 includes a sealing section 101, a solid cylindrical section 102, a hollow conical section 103 and a hollow cylindrical section 107 arranged in sequence from top to bottom, the sealing section 101 extends into the working sleeve 903, and a sealing ring is arranged on the outer periphery of the sealing section 101, which is in sealing contact with the inner wall of the working sleeve 903 to form a sealing cavity 24, the diameter of the hollow cylindrical section 107 is larger than the diameter of the sealing section 101, a limiting shoulder 105 is arranged on the outer side of the side wall of the hollow cylindrical section 107, and a first movable The through hole 104 is plugged, and a second piston through hole 106 is arranged on the side wall of the hollow cylindrical section 107. The suspension mechanism 14 is also a tubular structure with an opening at the upper end. The hollow cylindrical section 107 extends into the suspension mechanism 14. Initially, the lower end of the hollow cylindrical section 107 is away from the positioning mechanism 13. When the piston 10 moves downward, the hollow cylindrical section 107 gradually approaches the positioning mechanism 13 until it contacts and unlocks the positioning mechanism 13. The hollow cylindrical section 107 continues to extend into the suspension structure 14, so that the limit shoulder 105 is against the upper end surface of the suspension mechanism 14, pushing the suspension mechanism 14, and then pushing the coring inner tube 19 to move downward.

[0039] Furthermore, the shell includes an upper shell 5, a middle shell 12 and a lower shell 18 which are threadedly connected in sequence from top to bottom, the drill bit 22 is threadedly connected to the lower end of the lower shell 18, the coring inner barrel 19 and the core claw 23 are threadedly connected, the mud pulse generator 1, the control drive module 2, the angular velocity sensor 3, the battery 4, the pressure compensation oil tank 6, the motor 7, the high-pressure pump 8 and the multi-channel electrical connector 9 are located in the upper shell 5, the motor 7 and the high-pressure pump 8 are arranged in the pressure compensation oil tank 6, the piston 10 and the suspension mechanism 14 are located in the middle shell 12, the coring inner barrel 19 is located in the lower shell 18, and the coring inner barrel 19 is made of non-magnetic metal material or high-strength non-metallic material.

[0040] Please refer to Figures 6 to 8 , Figure 6 A schematic structural diagram of a multi-channel electrical connector in a specific implementation of a coring tool for real-time monitoring of downhole core length provided by the present invention; Figure 7 for Figure 6 Middle AA section view; Figure 8 Bit Figure 6 Schematic diagram of direction B.

[0041] On the basis of the coring tool for real-time monitoring of downhole core length provided in the above specific embodiments, the multi-channel electrical connector 9 includes a disc 902, a connecting sleeve 901 disposed at the upper end of the disc 902, and a working sleeve 903 disposed at the lower end of the disc 902.

[0042] An oil pressure hole 904 connecting the connecting sleeve 901 and the working sleeve 903 is provided at the center of the disc 902. The output port of the high-pressure pump 8 extends into the connecting sleeve 901 and is sealed. When working, the high-pressure pump 8 inputs the hydraulic oil into the working sleeve 903 through the oil pressure hole 904, which is equivalent to inputting the hydraulic oil into the sealing cavity 24, so that the piston 10 is extended. Furthermore, a radially extending power-through hole 905 is provided on the side of the disc 902, and an axially extending power-insertion hole 907 is provided on the disc 902. The power-through hole 905 is connected to the power-insertion hole 907 to form a power-through structure for the upper cable to pass through. At the same time, a plurality of flow holes 906 are provided on the disc 902, and the flow holes 906 are arc-shaped holes. Specifically, it includes four evenly arranged flow holes 906, which are arranged around the working sleeve 903, the electric flow hole 905 is arranged at the interval between two adjacent flow holes 906, and the plug hole 907 is located inside the connecting sleeve 901, that is, one end opening of the plug hole 907 is located on the upper surface of the disc 902, and the other end lower shell of the plug hole 907 is located inside the disc 902, one end opening of the electric flow hole 905 is located inside the disc 902 and communicates with the plug hole 907, and the other end opening of the electric flow hole 905 is located on the outer peripheral side of the disc 902. Two groups of electric flow holes 905 and plug holes 907 can be set, and the number and arrangement of each channel can also be adjusted according to the situation, all within the protection scope of the present invention.

[0043] Furthermore, a support tube 11 is provided on the outer periphery of the working sleeve 903, the upper end of the support tube 11 abuts against the lower edge of the disc 902, and the line segment of the support tube 11 abuts against the step on the inner side of the middle shell 12, thereby fixing and stably supporting the multi-channel electrical connector 9.

[0044] The specific working process is:

[0045] (1) The core enters the coring inner cylinder 19 through the drill bit 22, and the core contacts the induction disk 21, pushing the induction disk 21 upward. The magnetic element 20 in the induction disk 21 interacts with the Hall element 17 on the coring inner cylinder 19 to generate a periodically changing induced electromotive force. The induced electromotive force is transmitted to the upper cable in the lower shell 18 through the lower cable 16 and the conductive slip ring 15, and then transmitted to the multi-channel electrical connector 9 through the middle shell 12 and the upper cable in the upper shell 5, and finally reaches the control drive module 2. The control drive module 2 encodes the induced electromotive force and sends it to the ground through the mud pulse generator 1. The ground receiving module decodes the encoded pulse signal to obtain the core length;

[0046] (2) When the coring operation is completed, the wellhead sends instructions to the wellbore by controlling the top drive or rotary table speed change;

[0047] (3) When the angular velocity sensor 3 in the coring tool receives the command of the speed change, it controls the motor 7 to rotate by controlling the driving module 2, thereby driving the high-pressure pump 8 to pump the hydraulic oil in the pressure compensation tank 6 into the sealed cavity 24;

[0048] (4) Under the action of the hydraulic pressure, the piston 10 moves downward until the positioning mechanism 13 is unlocked;

[0049] (5) When the stop shoulder 105 of the piston 10 contacts the suspension mechanism 14, the piston 10 pushes the suspension mechanism 14 and the coring inner tube 19 to continue to move downward. When the core claw 23 contacts the conical surface inside the drill bit 22, the core claw 23 will shrink, thereby completing the core cutting.

[0050] The coring tool for real-time monitoring of downhole core length provided by the present invention is introduced in detail above. Specific examples are used herein to illustrate the principle and implementation mode of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. It should be pointed out that for ordinary technicians in this technical field, without departing from the principle of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A coring tool for real-time monitoring of downhole core length, comprising a housing and a drill bit (22) mounted at the lower end of the housing, characterized in that: A mud pulse generator (1) and a control drive module (2) are arranged at the upper end of the shell, a coring inner barrel (19) is arranged at the lower end of the shell, a Hall element (17) is arranged on the side wall of the coring inner barrel (19) and is communicatively connected to the control drive module (2), a sensing disk (21) is arranged inside the coring inner barrel (19), and a magnetic element (20) is installed on the sensing disk (21), when coring, the core enters the coring inner barrel (19) and pushes the sensing disk (21) to move axially upward along the coring inner barrel (19), and the Hall element (17) detects the position of the magnetic element (20) and sends a signal to the control drive module (2).

2. The coring tool for real-time monitoring of downhole core length according to claim 1, characterized in that: A plurality of Hall elements (17) are embedded on the outer side of the side wall of the coring inner cylinder (19); the plurality of Hall elements (17) are arranged in sequence along the axial direction of the coring inner cylinder (19) and are connected in series via a lower cable (16); and a plurality of groups of lower cables (16) connected in series with the Hall elements (17) are evenly arranged along the circumferential direction on the side wall of the coring inner cylinder (19).

3. The coring tool for real-time monitoring of downhole core length according to claim 2, characterized in that: A core claw (23) is installed at the lower end of the coring inner cylinder (19), and the inner wall of the drill bit (22) is provided with a conical surface that converges inward from top to bottom. A power assembly is provided in the middle of the shell, and the power assembly can push the coring inner cylinder (19) to move downward along the axial direction of the shell, and the conical surface pushes the core claw (23) to converge to cut the core.

4. The coring tool for real-time monitoring of downhole core length according to claim 3, characterized in that: The power assembly comprises an angular velocity sensor (3), a battery (4), a pressure compensation oil tank (6), an electric motor (7), a high-pressure pump (8), a multi-channel electrical connector (9) and a piston (10). A working sleeve (903) is provided at the lower end of the multi-channel electrical connector (9). The upper end of the piston (10) is inserted into the working sleeve (903) to form a sealed cavity (24). The electric motor (7) drives the high-pressure pump (8) to work and inputs the hydraulic oil in the pressure compensation oil tank (6) into the sealed cavity (24) to push the piston (10) to move downward along the axial direction of the housing.

5. The coring tool for real-time monitoring of downhole core length according to claim 4, characterized in that: A suspension mechanism (14) is provided between the piston (10) and the coring inner cylinder (19), a positioning mechanism (13) cooperating with the suspension mechanism (14) is provided on the inner wall of the shell, and the piston (10) pushes the coring inner cylinder (19) through the suspension mechanism (14).

6. The coring tool for real-time monitoring of downhole core length according to claim 5, characterized in that: A conductive slip ring (15) is installed below the suspension mechanism (14); the lower cable (16) is connected to the conductive slip ring (15); the conductive slip ring (15) is connected to the control drive module (2) via an upper cable; and the upper cable passes through the multi-channel electrical connector (9).

7. The coring tool for real-time monitoring of downhole core length according to claim 6, characterized in that: The piston (10) comprises a sealing section (101), a solid cylindrical section (102), a hollow conical section (103) and a hollow cylindrical section (107) which are arranged in sequence from top to bottom; a limiting shoulder (105) is arranged on the outer side of the side wall of the hollow cylindrical section (107); a first piston through hole (104) is arranged on the side wall of the hollow conical section (103); a second piston through hole (106) is arranged on the side wall of the hollow cylindrical section (107); the sealing section (101) extends into the working sleeve (903); the hollow cylindrical section (107) extends into the suspension mechanism (14); and the limiting shoulder (105) can abut against the upper end surface of the suspension mechanism (14).

8. The coring tool for real-time monitoring of downhole core length according to claim 5, characterized in that: The shell comprises an upper shell (5), a middle shell (12) and a lower shell (18) which are threadedly connected in sequence from top to bottom; the mud pulse generator (1), the control drive module (2), the angular velocity sensor (3), the battery (4), the pressure compensation oil tank (6), the motor (7), the high-pressure pump (8) and the multi-channel electrical connector (9) are located in the upper shell (5); the piston (10) and the suspension mechanism (14) are located in the middle shell (12); and the coring inner cylinder (19) is located in the lower shell (18).

9. The coring tool for real-time monitoring of downhole core length according to any one of claims 4 to 8, characterized in that: The multi-channel electrical connector (9) comprises a disc (902), a connecting sleeve (901) arranged at the upper end of the disc (902) and a working sleeve (903) arranged at the lower end of the disc (902); an oil pressure hole (904) connecting the connecting sleeve (901) and the working sleeve (903) is arranged at the center of the disc (902); a radially extending electrical hole (905) is arranged on the side of the disc (902); an axially extending electrical plug-in hole (907) is arranged on the top of the disc (902); the electrical hole (905) is connected to the electrical plug-in hole (907); and a plurality of flow holes (906) are arranged on the disc (902).

10. The coring tool for real-time monitoring of downhole core length according to claim 9, characterized in that: A support tube (11) is provided on the outer periphery of the working sleeve (903), and the upper end of the support tube (11) abuts against the lower edge of the disc (902).

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