Dynamic adjustment telescopic rod with pressure self-balancing

Abstract

The present application belongs to the technical field of wireless measurement while drilling, and specifically discloses a dynamic adjusting telescopic rod with pressure self-balancing, which comprises a telescopic rod body, a threaded head, an outer cylinder, a centralizer, a threaded sleeve and a connecting outer cylinder connected in a head-to-tail manner, and a connecting body inside which constitutes a communicating cavity; the cavity is provided with the telescopic rod body, a balance piston for adjusting pressure balance, a plug and a socket and a channel for wire connection. The present application has a large length adjusting range, and the connector docking is convenient and reliable, and has pressure self-balancing capability, and is suitable for wireless measurement while drilling instrument string connection.

Description

Technical Field

[0001] This invention relates to the field of wireless measurement-while-drilling instruments, and in particular to a dynamically adjustable telescopic rod with pressure self-balancing. Background Technology

[0002] Measurement While Drilling (MWD) systems, as core technologies in modern oil drilling engineering, play a crucial role in real-time monitoring and data transmission of downhole parameters. In directional drilling operations under complex geological conditions, precise wellbore trajectory control, real-time formation parameter acquisition, and safe and efficient drilling operations all heavily rely on the reliability of the MWD.

[0003] As a core connecting component in the MWD instrument string, the performance of the telescopic boom directly affects the stability and data accuracy of the entire measurement system. In the MWD instrument assembly, the telescopic boom primarily performs three functions: mechanically connecting instrument modules (such as resistivity logging tools, azimuth gamma meters, mud pulse generators, etc.); dynamically adjusting the length of the instrument string to accommodate different specifications of non-magnetic drill collars; and protecting internal cables and ensuring stable signal transmission in the high-temperature, high-pressure mud environment.

[0004] With the development of unconventional oil and gas resources in China, drilling operations face challenges such as deeper wells (>5000 meters), higher geothermal strata (>3℃ / 100 meters), and more complex formation structures. Traditional direct-connection cable solutions have the following problems: 1. Length adaptability: The specifications of non-magnetic drill collars used in oilfields vary, and there are dimensional differences due to repairs, requiring the telescopic rod to have a wide range of adjustability to meet the precise positioning requirements of the instruments. 2. Difficult connector insertion and removal: The narrow operating space can easily lead to bending and deformation of the pins or misalignment of the sealing rings, resulting in increased contact resistance or even short circuits. 3. Pressure balance problem: The pressure difference between the inside of the rod and the wellbore causes the sealing structure to age faster, with a mean time between failures (MTBF) of less than 500 hours. Summary of the Invention

[0005] To address the aforementioned challenges, this invention provides a dynamically adjustable telescopic rod with a wide length adjustment range and convenient connector docking, featuring pressure self-balancing, for use in MWD instrument string connections.

[0006] The technical solution of the present invention is as follows: a dynamic adjustable telescopic rod with pressure self-balancing, comprising a telescopic rod body, a threaded head, an outer cylinder, a straightening rod, a threaded sleeve, and a connecting outer cylinder connected end to end to form a connecting body, wherein the connecting body forms a communicating cavity inside;

[0007] One end of the telescopic rod is slidably fitted inside the threaded head, and the other end of the threaded head is threadedly connected to the outer cylinder.

[0008] One end of the telescopic rod is fixedly provided with a slip ring socket for external electrical connection, and the other end of the telescopic rod is slidably connected to an isolation tube. The other end of the isolation tube is threadedly connected to the center hole of the straightening rod. A telescopic spring is sleeved on the isolation tube, and the two ends of the telescopic spring are respectively in contact with the straightening rod and the telescopic rod.

[0009] The inside of the straightening rod, away from the isolation tube, is provided with a five-core contact plug and a five-core slip ring socket in contact with each other. A sealing plug is provided inside the threaded sleeve. The five-core slip ring socket is connected to the sealing plug through a wire. The sealing plug is connected to the slip ring socket assembly at the far end through a wire.

[0010] The threaded sleeve has a stepped cavity inside. An oil injection hole is opened on the side wall of the cavity with a smaller diameter. An oil plug is installed in the oil injection hole. A drain hole is opened on the side wall of the cavity with a larger diameter. An isolation sleeve is installed inside the stepped cavity of the threaded sleeve. The inner cavity of the isolation sleeve is circulated with oil, and the outer cavity is circulated with water. A balance piston and a compensation spring are slidably fitted on the outer side of the isolation sleeve.

[0011] The outer cylinder of the connector is threaded to a socket front end at one end away from the threaded sleeve. The socket front end is in contact with the slip ring socket assembly. The front end of the slip ring socket assembly is fixedly connected to the spring cavity inner sleeve, and a spring is provided inside the spring cavity inner sleeve.

[0012] A sealing rod slides through the front end of the socket and the slip ring socket assembly, abutting against the spring.

[0013] Furthermore, the two ends of the connector are respectively threaded with a protective cap and a tail cap, and the ends of the connector are plugged when not in use.

[0014] Furthermore, a spring seat is threadedly connected to the end of the telescopic rod, with one end of the telescopic spring abutting against the end of the straightening rod and the other end abutting against the end of the spring seat.

[0015] Furthermore, the isolation tube is a hollow tube, and the wires on the slip ring socket pass through the telescopic rod, the isolation tube, and the straightening rod to connect to the five-core contact plug;

[0016] The five-core slip ring socket has a conductive ring, which is connected to a sealing plug set inside the threaded sleeve via a wire. The sealing plug is then connected to the slip ring socket assembly via a wire passing through the inner cavity of the connecting outer cylinder.

[0017] Furthermore, the inner sleeve of the spring cavity is provided with two stages of springs, which are connected by a spring seat. A stepped screw is provided at the end of the inner sleeve of the spring cavity. One end of the two stages of springs abuts against the sealing rod, and the other end abuts against the stepped screw.

[0018] Furthermore, the slip ring socket assembly and the outer side of the inner spring cavity sleeve are provided with a spring cavity outer sleeve. The spring cavity outer sleeve is fixed inside the connecting outer cylinder, one end of which is in contact with the front end of the socket, and the other end is provided with a socket rear end cover. The socket rear end cover is fixedly connected to the spring cavity outer sleeve.

[0019] Compared with existing technologies, this invention provides a dynamically adjustable telescopic rod with pressure self-balancing. The buffer chamber is connected to the drilling fluid via a drain hole on the threaded sleeve, automatically balancing the internal oil pressure using mud pressure to avoid sealing failure caused by high pressure differentials. Furthermore, the telescopic rod body allows adjustment of the entire telescopic rod length according to the drill collar length, ensuring constant contact between the connecting outer cylinder and the instruments inside the non-magnetic drill collar, further preventing key debonding. Moreover, the connector uses a contact-slip ring connection method, effectively preventing pin bending and deformation, greatly increasing the reliability of the telescopic rod. Attached Figure Description

[0020] Figure 1 This is a cross-sectional structural schematic diagram of a dynamically adjustable telescopic rod with pressure self-balancing according to the present invention.

[0021] Figure 2 This is a structural diagram of the telescopic adjustment part of the dynamically adjustable telescopic rod of the present invention;

[0022] Figure 3 This is a structural diagram of the internal pressure compensation part of the dynamically adjustable telescopic rod of the present invention;

[0023] Figure 4 This is a schematic diagram of the threaded sleeve of the dynamically adjustable telescopic rod of the present invention;

[0024] Figure 5 This is a structural diagram of the end elastic connection part of the dynamically adjustable telescopic rod of the present invention.

[0025] In the diagram: 1-Telescopic rod body, 2-Slip ring socket, 3-Threaded head, 4-Spring seat, 5-Telescopic spring, 6-Isolation tube, 7-Outer cylinder, 8-Straightening rod, 9-Rubber wing, 10-Five-pin contact plug, 11-Five-pin slip ring socket, 12-Threaded sleeve, 13-Oil plug, 14-Balance piston, 15-Isolation sleeve, 16-Protective cap, 17-Connecting outer cylinder, 18-Drain hole, 19-Socket rear end cover, 20-Spring cavity outer sleeve, 21-Step screw, 22-Spring No. 1, 23-Spring seat, 24-Spring No. 2, 25-Slip ring socket assembly, 26-Sealing rod, 27-Socket front end head, 28-Tail cap, 29-Compensating spring, 30-Spring cavity inner sleeve. Detailed Implementation

[0026] The present invention will now be described in detail with reference to the accompanying drawings and embodiments, wherein the drawings constitute a part of this application and are used together with the embodiments of the present invention to illustrate the present invention. However, those skilled in the art should understand that the following embodiments are not the only limitation on the technical solutions of the present invention, and any equivalent transformations or modifications made under the spirit and essence of the technical solutions of the present invention should be considered as falling within the protection scope of the present invention.

[0027] like Figure 1 As shown, the present invention provides a dynamically adjustable telescopic rod with pressure self-balancing. From the external structure, the telescopic rod includes: telescopic rod body 1, protective cap 16, threaded head 3, outer cylinder 7, straightening rod 8, threaded sleeve 12, connecting outer cylinder 17 and tail cap 28.

[0028] The telescopic pole 1 is a variable diameter design. The end of the telescopic pole 1 with the larger diameter is connected to the protective cap 16. The protective cap 16 is threaded to the telescopic pole 1 and blocks the end of the telescopic pole to protect the internal components of the telescopic pole from damage and dirt. A threaded head 3 is movably fitted onto the smaller diameter end of the telescopic rod 1. The threaded head 3 is used to protect the rod and connect to the next stage component. The telescopic rod 1 and the threaded head 3 are slidably connected and sealed with a sealing ring. The telescopic rod 1 is pressed by a telescopic spring 5 at its front end, changing its connection position with the threaded head 3. The end of the threaded head 3 away from the telescopic rod 1 is inserted into the outer cylinder 7 and threadedly connected to it. The end of the outer cylinder 7 away from the threaded head 3 is threadedly connected to a straightening rod 8, and the end of the straightening rod 8 is threadedly connected to the inside of the outer cylinder 7. The end of the straightening rod 8 away from the outer cylinder 7 is threadedly connected to a threaded sleeve 12, and the end of the threaded sleeve 12 is threadedly connected to the inside of the straightening rod 8. The end of the threaded sleeve 12 away from the straightening rod 8 is threadedly connected to the outer cylinder 17, and the end of the connecting outer cylinder 17 is threadedly connected to the inside of the threaded sleeve 12. A tail cap 28 is provided at the end of the connecting outer cylinder 17 away from the threaded sleeve 12. The tail cap 28 is threadedly connected to the connecting outer cylinder 17 and is used to plug the end of the connecting outer cylinder 17 to prevent damage and contamination to its internal components. The outside of the straightening rod 8 is evenly distributed with several rubber wings 9 along its circumference. Each rubber wing 9 is fixed to the straightening rod 8 as a whole for auxiliary straightening. The connecting outer cylinder 17 has external threads that can be screwed into the instrument inside the non-magnetic drill collar. The above connections constitute the overall external configuration of the telescopic rod of the present invention. When in operation, the protective cap 16 and the tail cap 28 can be removed, and the telescopic rod can be connected to other instruments.

[0029] From an internal structural perspective, the telescopic rod includes: a slip ring socket 2, a spring seat 4, a telescopic spring 5, an isolation tube 6, a five-pin contact plug 10, a five-pin slip ring socket 11, an oil plug 13, a balance piston 14, an isolation sleeve 15, a socket rear end cover 19, a spring cavity outer sleeve 20, a stepped screw 21, a first spring 22, a spring seat 23, a second spring 24, a slip ring socket assembly 25, a sealing rod 26, a socket front end head 27, a compensating spring 29, and a spring cavity inner sleeve 30. The telescopic rod has a hollow core for cable routing.

[0030] The telescopic rod 1 is a hollow rod with a slip ring socket 2 installed inside the larger inner diameter end. The slip ring socket 2 is fixedly connected to the telescopic rod 1, and the slip ring socket 2 is connected to the slip ring plug on the MWD instrument to achieve signal conduction.

[0031] The smaller-diameter end of the telescopic rod 1 is slidably connected to the isolation tube 6. The telescopic rod 1 is sleeved on the outside of the isolation tube 6 and can slide and extend along the outer wall of the isolation tube 6. The other end of the isolation tube 6 is threadedly connected to the center hole of the straightening rod 8. A telescopic spring 5 is sleeved on the outside of the isolation tube 6. The telescopic spring 5 is set inside the outer cylinder 7, and its two ends are in contact with the straightening rod 8 and the telescopic rod 1, respectively. Furthermore, since the wall of the telescopic rod 1 is thin and the rod diameter is small at the end connected to the isolation tube 6, a spring seat 4 is threadedly connected to the end of the telescopic rod 1. The spring seat 4 is sleeved on the outside of the isolation tube 6 simultaneously with the telescopic rod 1, and the spring seat 4 blocks the telescopic spring 5. The spring seat 4 is slidably installed inside the outer cylinder 7, with one end in contact with the telescopic spring 5 and the other end in contact with the end of the threaded head 3. The obstruction of the threaded head 3 prevents the telescopic rod 1 from coming out of the threaded head 3. By compressing the spring 5, the telescopic rod 1 can move into the outer cylinder 7 or pop out of the outer cylinder 7. Depending on the on-site usage conditions, the telescopic rod 1, telescopic spring 5, and outer cylinder 7 can be available in various length specifications to meet the on-site requirements for a wide range of adjustability.

[0032] Both the isolation tube 6 and the straightening rod 8 are hollow. A five-pin contact plug 10 is fixedly connected (usually by a threaded connection) to the end of the straightening rod 8 furthest from the isolation tube 6. The five-pin contact plug 10 is in contact with a five-pin slip ring socket 11, which is fixedly installed at one end of a threaded sleeve 12. A sealing plug is located inside the threaded sleeve 12. Each conductive ring on the five-pin slip ring socket 11 is connected to the sealing plug via a wire. The sealing plug is connected to the slip ring socket assembly 25 at the far end via a wire. One end of the threaded sleeve 12 is threadedly connected to the straightening rod 8, and the other end is threadedly connected to the connecting outer cylinder 17.

[0033] The threaded sleeve 12 has a stepped cavity inside. An oil injection hole is opened on the side wall of the cavity with a smaller diameter. An oil plug 13 is installed in the oil injection hole. The oil plug 13 is threadedly connected to the threaded sleeve 12. The oil injection hole of the threaded sleeve 12 can be blocked by the oil plug 13. Several drainage holes 18 are opened on the side wall of the cavity with a larger diameter. The drainage holes 18 can introduce mud into the cavity of the threaded sleeve 12.

[0034] An isolation sleeve 15 is threadedly connected to one end of the outer cylinder 17 near the threaded sleeve 12. The isolation sleeve 15 is located inside the cavity of the threaded sleeve 12 to isolate oil and water. Specifically, the isolation sleeve 15 blocks the stepped cavity inside the threaded sleeve 12. The isolation sleeve 15 has an inner cavity for oil passage, and the outer cavity of the isolation sleeve 15 communicates with the drain hole 18. A balance piston 14 and a compensation spring 29 are slidably mounted on the outer side of the isolation sleeve 15. The compensation spring 29 is in contact with the balance piston 14 and the isolation sleeve 15. The isolation sleeve 15, the balance piston 14, and the compensation spring 29 are all inserted into the cavity of the threaded sleeve 12. The outer end of the balance piston 14 is blocked by the shoulder of the cavity of the threaded sleeve 12. The balance piston 14 slides in the cavity according to the pressure change in the cavity to perform pressure compensation and maintain the internal and external pressure balance.

[0035] The cavity of the outer cylinder 17 is provided with a socket front end 27, a slip ring socket assembly 25, a sealing rod 26, a first spring 22, a second spring 24, an inner spring cavity sleeve 30, and an outer spring cavity sleeve 20.

[0036] A socket front end 27 is provided at the end of the connecting outer cylinder 17 away from the threaded sleeve 12. The socket front end 27 is embedded into the connecting outer cylinder 17 and threadedly connected to the connecting outer cylinder 17. A slip ring socket assembly 25 is provided at the end of the connecting outer cylinder 17 near the socket front end 27. The slip ring socket assembly 25 is in contact with the socket front end 27.

[0037] A spring cavity inner sleeve 30 is fixedly connected to the end of the slip ring socket assembly 25 away from the front end 27 of the socket. A stepped screw 21 is provided at the end of the spring cavity inner sleeve 30 away from the slip ring socket assembly 25. The stepped screw 21 passes into the inside of the spring cavity inner sleeve 30 and is threadedly connected to the spring cavity inner sleeve 30. Spring 22 and spring 24 are both installed in the spring cavity inner sleeve 30 and are connected by a spring seat 23. The purpose of setting spring 22 and spring 24 is to shorten the stroke of a single spring and improve the elastic performance.

[0038] A sealing rod 26 passes through the middle of the slip ring socket assembly 25 and the socket front end head 27 and is slidably connected to both; the front end of the sealing rod 26 extends into the inner sleeve 30 of the spring cavity and abuts against one end of the combination of spring 22 and spring 24, and the stepped screw 21 at the other end of the inner sleeve 30 of the spring cavity abuts against the other end of the combination of spring 22 and spring 24.

[0039] A spring cavity outer sleeve 20 is provided on the outer side of the inner spring cavity sleeve 30. The spring cavity outer sleeve 20 is fixed inside the connecting outer cylinder 17. One end of the spring cavity outer sleeve 20 is in contact with the end of the front end 27 of the socket. The end of the spring cavity outer sleeve 20 away from the front end 27 of the socket is provided with a socket rear end cover 19, which is fixedly connected to the spring cavity outer sleeve 20. The spring cavity outer sleeve 20 is used to protect the inner spring cavity sleeve 30 and the slip ring socket assembly 25.

[0040] The working principle of this invention is as follows: Before use, remove the caps 16 and tail caps 28 from both ends of the telescopic rod, connect the telescopic rod body 1 to the MWD instrument and tighten it, connect the slip ring socket 2 to the slip ring plug on the MWD instrument, connect the slip ring socket 2 to the five-pin contact plug 10 via a wire, connect each pin on the five-pin contact plug 10 to the conductive ring on the end face of the five-pin slip ring socket 11, connect each conductive ring on the five-pin slip ring socket 11 via a wire, and connect the sealed plug to the slip ring socket assembly 25 via a wire. At this point, the slip ring socket 2 and the slip ring socket assembly 25 are connected.

[0041] At this point, the telescopic rod is inserted into the non-magnetic drill collar with the slip ring socket assembly 25 facing downwards. As the telescopic rod is lowered, the sealing rod 26 will contact the slip ring plug of the instrument inside the non-magnetic drill collar and gradually retract. The retraction of the sealing rod 26 causes the second spring 24 to compress and the spring seat 23 to move. The movement of the spring seat 23 causes the first spring 22 to compress until the flange face of the slip ring plug is completely in contact with the front end 27 of the socket. At this time, each conductive ring on the slip ring plug and each spring contact finger on the slip ring socket assembly 25 make corresponding contact to conduct communication.

[0042] Before leaving the factory, the telescopic rod is pre-pressurized by removing the oil plug 13 on the threaded sleeve 12 and filling the inner cavity of the threaded sleeve 12 with oil. At this time, the balance piston 14 will slide towards the compression compensation spring 29 under the internal pressure until the compensation spring 29 is compressed to the limit position.

[0043] When the telescopic rod is inserted into the non-magnetic drill collar, the mud inside the non-magnetic drill collar will enter the threaded sleeve 12 along the drain hole on the threaded sleeve 12 and gradually move the balance piston 14 in the direction of relaxing the compensation spring 29. The movement of the balance piston 14 compresses the oil in the inner cavity of the isolation sleeve 15, increasing the internal pressure until the internal pressure is consistent with the external mud pressure, and the balance piston 14 no longer slides.

[0044] If the length of the instrument string is greater than the length of the non-magnetic drill collar, the instrument string can be pressed down further, causing the telescopic rod 1 to slide and compress towards the outer cylinder 7. Under the reaction force of the telescopic spring 5, the connecting outer cylinder 17 and the instrument inside the non-magnetic drill collar will always remain in contact, further preventing debonding.

[0045] While embodiments of the present invention have been shown and described above, it will be understood by those skilled in the art that various changes, modifications, substitutions or alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A dynamically adjusting telescopic pole with pressure self-balancing, characterized in that, The connector consists of a telescopic rod (1), a threaded head (3), an outer cylinder (7), a straightening rod (8), a threaded sleeve (12), and a connecting outer cylinder (17), with the interior of the connector forming a communicating cavity. One end of the telescopic rod (1) is slidably sleeved inside the threaded head (3), and the other end of the threaded head (3) is threadedly connected to the outer cylinder (7); One end of the telescopic rod (1) is fixedly provided with a slip ring socket (2) for electrical connection to the outside. The other end of the telescopic rod (1) is slidably connected to an isolation tube (6). The other end of the isolation tube (6) is threadedly connected to the center hole of the straightening rod (8). The isolation tube (6) is fitted with a telescopic spring (5). The two ends of the telescopic spring (5) are respectively in contact with the straightening rod (8) and the telescopic rod (1). A spring seat (4) is threadedly connected to the end of the telescopic rod (1). One end of the telescopic spring (5) abuts against the end of the straightening rod (8), and the other end abuts against the end of the spring seat (4). The straightening rod (8) is provided with a five-core contact plug (10) and a five-core slip ring socket (11) at the end away from the isolation tube (6). A sealing plug is provided inside the threaded sleeve (12). The five-core slip ring socket (11) is connected to the sealing plug through a wire. The sealing plug is connected to the slip ring socket assembly (25) at the far end through a wire. The threaded sleeve (12) has a stepped cavity inside. An oil injection hole is opened on the side wall of the cavity with a smaller diameter, and an oil plug (13) is installed in the oil injection hole. A drain hole (18) is opened on the side wall of the cavity with a larger diameter. An isolation sleeve (15) is installed inside the stepped cavity of the threaded sleeve (12). The inner cavity of the isolation sleeve (15) is circulated with oil, and the outer cavity is circulated with water. A balance piston (14) and a compensation spring (29) are slidably fitted on the outer side of the isolation sleeve (15). The isolation sleeve (15), the balance piston (14), and the compensation spring (29) are all integrated into the threaded sleeve. (12) In the cavity, the outer end of the balance piston (14) is blocked by the cavity shoulder of the threaded sleeve (12). The balance piston (14) slides in the cavity to compensate for pressure changes and maintain the internal and external pressure balance. The end of the connecting outer cylinder (17) away from the threaded sleeve (12) is threadedly connected to the front end of the socket (27). The front end of the socket (27) is in contact with the slip ring socket assembly (25). The front end of the slip ring socket assembly (25) is fixedly connected to the inner sleeve of the spring cavity (30). A spring is provided in the inner sleeve of the spring cavity (30). A sealing rod (26) slides through the front end of the socket (27) and the slip ring socket assembly (25) and abuts against the spring; The inner sleeve (30) of the spring cavity is provided with two-stage springs, which are connected by a spring seat (23). The end of the inner sleeve (30) of the spring cavity is provided with a stepped screw (21). One end of the two-stage springs abuts against the sealing rod (26), and the other end abuts against the stepped screw (21). The slip ring socket assembly (25) and the outer side of the spring cavity inner sleeve (30) are provided with a spring cavity outer sleeve (20). The spring cavity outer sleeve (20) is fixed inside the connecting outer cylinder (17). One end is in contact with the end of the socket front head (27), and the other end is provided with a socket rear end cover (19). The socket rear end cover (19) is fixedly connected to the spring cavity outer sleeve (20).

2. The self-leveling telescopic rod with pressure self-balancing according to claim 1, characterized in that, The connector is threaded to a protective cap (16) and a tail cap (28) at both ends, and the ends of the connector are plugged when not in use.

3. The dynamically adjustable telescopic rod with pressure self-balancing as described in claim 1, characterized in that, The isolation tube (6) is a hollow tube, and the wires on the slip ring socket (2) pass through the telescopic rod (1), the isolation tube (6) and the straightening rod (8) and are connected to the five-core contact plug (10); The five-core slip ring socket (11) has a conductive ring, which is connected to the sealing plug provided in the threaded sleeve (12) by a wire. The sealing plug is then connected to the slip ring socket assembly (25) by a wire passing through the inner cavity of the connecting outer cylinder (17).

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