High-power alternating-current and direct-current coaxial downhole connector

Abstract

A high-power alternating-current and direct-current coaxial downhole connector, comprising: a female connector (1), comprising two first direct-current conductive rings (11) and three first alternating-current conductive rings (12), wherein a first plug connector (14) is arranged on a first plastic insulating sleeve (13), and two first direct-current receptacle holes (141) and three first alternating-current receptacle holes (142) are arranged on the first plug connector (14); and a male connector (2), comprising a positioning rod (25), wherein a conductive rod (26) is sleeved on the positioning rod (25), and two second direct-current conductive rings (21) and three second alternating-current conductive rings (22) are arranged on the conductive rod (26). The present invention has a small size, allows for simultaneous transmission of high-power power and direct-current carrier communication, has reliable direct-current carrier transmission efficiency, and effectively solves the problem of real-time control and signal transmission in downhole electric drilling tools.

Description

Downhole high-power AC / DC coaxial connector

[0001] Related applications

[0002] This application claims priority to the Chinese invention patent with patent application number 202310763900.0, application date June 26, 2023, and invention name “Downhole small size high power coaxial connector”. Technical Field

[0003] The present invention relates to the field of drilling equipment in the petroleum industry, and in particular to a downhole high-power AC / DC coaxial connector, which is a key component used in coiled tubing electric drilling technology. Background Art

[0004] Currently, coiled tubing drilling technology, both domestically and internationally, primarily relies on mechanical motors as power tools. The connectors used in these systems primarily provide low-voltage DC power and carrier communications for various downhole functional modules. These connectors are generally low-power, 2- to 5-core structures. Compared to mechanical drilling tools, electric drilling tools offer the advantages of efficient power output under low hydraulic efficiency conditions and ease of high-speed control. This addresses the limited power output required for coiled tubing drilling, enabling rapid drilling at low drilling pressure and high speed. Their infinitely adjustable speed and torque facilitate closed-loop automated control of drilling parameters, improving ROP and drill bit footage while reducing tripping times.

[0005] A downhole electric drill and coiled tubing electric drilling system is currently available. The connector in this system is a two-core rotary coaxial structure with a rated voltage of 750V and a rated current of 52A. The male connector's conductive ring is a solid copper ring, separated by insulating rubber between the two phases. The female connector's conductive ring is a fixed lantern spring structure, and both male and female connectors are integrally injection-molded. This downhole connector only provides power for the electric drill and cannot provide power or signal transmission for the various functional subs downhole. Its functionality is limited. The connector is large, providing low electrical power. It also suffers from poor waterproofing and unstable insulation. Installation and disassembly are cumbersome, making on-site replacement and cleaning difficult.

[0006] Therefore, the inventors, relying on their many years of experience and practice in related industries, have proposed an underground high-power AC / DC coaxial connector to overcome the defects of the prior art.

[0007] Summary of the Invention

[0008] The purpose of the present invention is to provide a downhole high-power AC / DC coaxial connector that realizes a small size, simultaneous transmission of high-power power electricity and DC carrier communication, with a maximum transmission power of 70kW, high temperature and high pressure resistance, and reliable DC carrier transmission efficiency. It effectively solves the bottleneck problem of long-distance power transmission and signal transmission failure in coiled tubing drilling technology, ensuring the safe and smooth operation of the entire system.

[0009] The object of the present invention is achieved by providing an underground high-power AC / DC coaxial connector, comprising:

[0010] A female connector includes two first DC conductive rings and three first AC conductive rings arranged along an axial direction with insulating spacing therebetween. Each of the first DC conductive rings and each of the first AC conductive rings are integrally connected by injection molding via a first plastic insulating sleeve, the first end of which is open. A first plug connector is provided at the second end of the first plastic insulating sleeve, and the first plug connector and the first plastic insulating sleeve are integrally connected via an integrated injection molding sleeve. The first plug connector is provided with two first DC jacks and three first AC jacks. Each of the first DC conductive rings is electrically connected to each of the first DC jacks, and each of the first AC conductive rings is electrically connected to each of the first AC jacks.

[0011] The male connector of the connector can be coaxially plugged into the female connector of the connector, including a positioning rod, a conductive rod is sleeved on the positioning rod, and two second DC conductive rings that can contact the first DC conductive ring and three second AC conductive rings that can contact the first AC conductive ring are provided inwardly at the second end of the conductive rod. A second plug connector is provided at the first end of the conductive rod, and two second DC jacks and three second AC jacks are provided on the second plug connector. Each second DC conductive ring is electrically connected to each second DC jack, and each second AC conductive ring is electrically connected to each second AC jack; each second DC conductive ring, each second AC conductive ring and the conductive rod are injection-molded into one piece via a second plastic insulating sleeve.

[0012] As described above, the downhole high-power AC / DC coaxial connector of the present invention has the following beneficial effects:

[0013] The present invention provides a downhole high-power AC / DC coaxial connector. Two DC conductive rings and three AC conductive rings are provided on both the male connector and the female connector, forming a five-core coaxial rotating plug-in structure, realizing the plug-in connection of a three-core AC power cable and a two-core DC cable, providing high-power power for downhole electric drilling tools, and at the same time providing power and DC carrier communication for various functional short sections downhole; each conductive ring of the female connector is insulated and protected by a first plastic insulating sleeve, and each conductive ring of the male connector is insulated and protected by a second plastic insulating sleeve. The entire connector is injection molded using a high-temperature integrated process, and has reliable strength and insulation performance, meeting the requirements of downhole drilling tools. The invention can realize the sealing of downhole high-pressure environment, insulation of high-voltage and high-current environment, multiple plugging and unplugging, and reliability in mud acid and alkali corrosion environment; the tails of the male connector and the female connector are respectively provided with corresponding plug-in connectors, which have the functions of self-cleaning, quick replacement and maintenance; the present invention realizes the small size of the downhole connector, the simultaneous transmission of high-power power electricity and DC carrier communication, the maximum transmission power reaches 70kW, it is resistant to high temperature and high pressure, and the DC carrier transmission efficiency is reliable, which effectively solves the real-time control and signal transmission problems of downhole electric drilling tools, and effectively solves the bottleneck problem of long-distance power transmission and signal transmission failure in continuous pipe drilling technology, and ensures the safe and smooth operation of the entire system. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0015] in:

[0016] Figure 1 is a schematic diagram of the downhole high-power AC / DC coaxial connector of the present invention.

[0017] FIG2 is a cross-sectional view of the female connector of the present invention.

[0018] Figure 3: A view in the direction of Figure 2.

[0019] FIG4 is a cross-sectional view of the male connector of the present invention.

[0020] Figure 5: This is the B-direction view in Figure 4. DETAILED DESCRIPTION

[0021] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, specific embodiments of the present invention are now described with reference to the accompanying drawings.

[0022] The specific embodiments of the present invention described herein are intended only to illustrate the present invention and are not to be construed as limiting the present invention in any way. In light of the present invention, a skilled person may conceive of any possible variations based on the present invention, all of which should be considered to fall within the scope of the present invention. It should be noted that when an element is referred to as being "disposed on" another element, it may be directly on the other element or there may be an intermediate element. When an element is considered to be "connected" to another element, it may be directly connected to the other element or there may be an intermediate element at the same time. The terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to mechanical or electrical connections, or to internal communication between two elements, and may be directly connected or indirectly connected through an intermediate medium. A person of ordinary skill in the art can understand the specific meanings of the above terms based on the specific circumstances. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only implementation methods.

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application pertains. The terms used herein in the specification of this application are intended only to describe specific embodiments and are not intended to limit this application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0024] As shown in Figures 1 to 5, the present invention provides a downhole high-power AC / DC coaxial connector, comprising:

[0025] The female connector 1 includes two first DC conductive rings 11 and three first AC conductive rings 12 (each conductive ring constitutes one phase) arranged along the axial insulation interval. Each first DC conductive ring 11 and each first AC conductive ring 12 are connected together by injection molding through a first plastic insulating sleeve 13 (PEEK modified, reinforced and toughened polymer plastic material is used as an insulator, and is injection molded at high temperature). The first end of the first plastic insulating sleeve 13 is open; the second end of the first plastic insulating sleeve 13 is provided with a first plug connector 14. The first plug connector 14 It is connected to the first plastic insulating sleeve 13 through an integrated injection-molded sleeve 15; two first DC jacks 141 and three first AC jacks 142 are provided on the first plug connector 14, and each first DC conductive ring 11 is electrically connected to each first DC jack 141, and each first AC conductive ring 12 is electrically connected to each first AC jack 142; the outer wall size of the integrated injection-molded sleeve 15 of the connector female connector 1 constitutes the outer diameter size of the downhole high-power AC / DC coaxial connector of the present invention, which is greatly reduced compared with the external dimensions of the connector in the prior art.

[0026] The male connector 2 can be coaxially plugged into the female connector 1 and includes a positioning rod 25, on which a conductive rod 26 is sleeved. Two second DC conductive rings 21 capable of contacting the first DC conductive ring 11 and three second AC conductive rings 22 capable of contacting the first AC conductive ring 12 are disposed inwardly at the second end of the conductive rod 26. A second plug connector 24 is disposed at the first end of the conductive rod 26. Two second DC jacks 241 and three second AC jacks 242 are disposed on the second plug connector 24. Each second DC conductive ring 21 is electrically connected to each second DC jack 241, and each second AC conductive ring 22 is electrically connected to each second AC jack 242. The second DC conductive rings 21, each second AC conductive ring 22, and the conductive rod 26 are integrally connected by injection molding via a second plastic insulating sleeve 23.

[0027] The first plastic insulating sleeve 13 and the second plastic insulating sleeve 23 are both insulators made of a polymer plastic material modified by PEEK and reinforced to enhance toughness. A reasonable insulation spacing is designed to ensure a safe creepage distance.

[0028] Downhole connectors are key components in cabled continuous tubing drilling systems, connecting cables, non-rotating connectors, various downhole functional modules, and electric motors. Currently, challenges such as reliable sealing and insulation technology in small connector footprints severely restrict the development of long-distance power and signal transmission technology. Connector failure can directly short-circuit downhole tools, risking damage. To address these challenges, the present invention proposes a downhole high-power AC / DC coaxial connector. This invention is a key component in cabled continuous tubing electric drilling systems, connecting cables with various downhole functional modules and electric motors.

[0029] In a specific embodiment, the rated voltage of the underground high-power AC / DC coaxial connector is greater than 1000V, the rated current is greater than 100A, the maximum transmission power is 70kW, and the overall outer diameter is less than 50mm, meeting the requirements of small size and high power.

[0030] The present invention provides a downhole high-power AC / DC coaxial connector. Two DC conductive rings and three AC conductive rings are provided on both the male connector and the female connector, forming a five-core coaxial rotating plug-in structure, realizing the plug-in connection of a three-core AC power cable and a two-core DC cable, providing high-power power for downhole electric drilling tools, and at the same time providing power and DC carrier communication for various functional short sections downhole; each conductive ring of the female connector is insulated and protected by a first plastic insulating sleeve, and each conductive ring of the male connector is insulated and protected by a second plastic insulating sleeve. The entire connector is injection molded using a high-temperature integrated process, and has reliable strength and insulation performance, meeting the requirements of downhole drilling tools. The invention can realize the sealing of downhole high-pressure environment, insulation of high-voltage and high-current environment, multiple plugging and unplugging, and reliability in mud acid and alkali corrosion environment; the tails of the male connector and the female connector are respectively provided with corresponding plug-in connectors, which have the functions of self-cleaning, quick replacement and maintenance; the present invention realizes the small size of the downhole connector, the simultaneous transmission of high-power power electricity and DC carrier communication, the maximum transmission power reaches 70kW, it is resistant to high temperature and high pressure, and the DC carrier transmission efficiency is reliable, which effectively solves the real-time control and signal transmission problems of downhole electric drilling tools, and effectively solves the bottleneck problem of long-distance power transmission and signal transmission failure in continuous pipe drilling technology, and ensures the safe and smooth operation of the entire system.

[0031] Further, as shown in Figure 4, each second DC conductive ring 21 and each second AC conductive ring 22 includes a male connector ring body, a dovetail groove is provided on the outer wall of the male connector ring body, and a contact spring is installed in the dovetail groove. The contact spring is in contact and electrically connected with each first DC conductive ring 11 or each first AC conductive ring 12.

[0032] Furthermore, the male connector ring body is made of beryllium bronze material, and the male connector ring body and the contact spring are both gold-plated, with a maximum current conduction capacity of more than 100A.

[0033] The first DC conductive ring 11 and the first AC conductive ring 12 of the connector female connector 1 are complete circular ring structures. The contact surfaces of the first DC conductive ring 11 and the first AC conductive ring 12 are polished and contact the contact spring of the connector male connector 2 after being plugged in, realizing the transmission of high-power electrical energy and carrier signals.

[0034] Furthermore, as shown in FIG4 , second DC conductive rings 21 and second AC conductive rings 22 are arranged inwardly from the second end of the positioning rod 25 at insulated intervals. Each second DC conductive ring 21 and each second AC conductive ring 22 is arranged in a stepped manner with increasing diameters. Male connector O-rings 27 are installed between adjacent second DC conductive rings 21, between adjacent second DC conductive rings 21 and second AC conductive rings 22, and between adjacent second AC conductive rings 22. The conductive rings are arranged in a stepped manner, and male connector O-rings 27 are installed between each phase to effectively isolate the water film.

[0035] Furthermore, as shown in Figures 4 and 5, five second conductive support rods of different lengths are extended from the first end to the second end of the conductive rod 26. The first end of each second conductive support rod is electrically connected to the second DC jack 241 or the second AC jack 242, and the second end of each second conductive support rod is electrically connected to the second DC conductive ring 21 or the second AC conductive ring 22.

[0036] Furthermore, the second conductive support rods are configured as flat round rods. Each second conductive support rod of the connector male connector 2 adopts a special flat round structure, with a PEEK sleeve and heat shrink tubing installed on the outside, effectively increasing the phase spacing while ensuring the conductive performance.

[0037] 2, a vulcanized rubber layer 16 is provided at each axial end of each first DC conductive ring 11 and each first AC conductive ring 12. The vulcanized rubber layer 16 protects the end surface of each conductive ring of the female connector 1 from moisture, thereby enhancing waterproof performance.

[0038] 2, a locking nut 17 is provided inside the first end of the first plastic insulating sleeve 13. After all parts are assembled and placed in the PEEK sleeve, they are locked and positioned before injection molding, effectively ensuring the quality of the injection molding.

[0039] The insulating portion of the underground high-power AC / DC coaxial connector of the present invention is injection molded using high-performance PEEK material through a high-temperature and high-pressure integrated process. The insulation distance between each phase of the connector female connector 1 and the connector male connector 2 is scientifically calculated and tested for verification. At the same time, a stepped structure is adopted between each phase to effectively increase the creepage distance. The insulating layer of the connector male connector 2 is additionally equipped with a male connector O-ring 27 between each phase for water film isolation, thereby achieving a self-cleaning function during insertion. The conductive rings and the insulating material contact end faces of the connector female connector 1 are all subjected to rubber vulcanization treatment, and O-rings are installed on the contact end faces for water film isolation. After the various parts are assembled, the entirety is placed in a PEEK sleeve for high-temperature injection molding.

[0040] Furthermore, as shown in Figures 2 and 3, five first conductive rods of different lengths are extended from the first plug connector 14 toward the first AC conductive ring 12. The first end of each first conductive rod is electrically connected to the first DC jack 141 or the first AC jack 142, and the second end of each first conductive rod is electrically connected to the first DC conductive ring 11 or the first AC conductive ring 12.

[0041] Furthermore, the first conductive support rod is set as a flat rod, with a heat shrink tube installed on the outside. A bridge lap structure is adopted between each phase, and each bridging conductive ring is processed with vulcanized rubber, which effectively ensures the radial creepage distance, increases the insulation performance, and effectively reduces the outer diameter of the connector.

[0042] Furthermore, each first DC conductive ring 11 and each first AC conductive ring 12 is made of beryllium copper and is gold-plated, with a maximum current conducting capacity of more than 100 A.

[0043] Furthermore, as shown in FIG1 and FIG2 , a first metal shell 18 is sleeved on the integrated injection molded sleeve 15 at a position opposite to the first plug connector 14 ; a second metal shell 28 is sleeved on the second plastic insulating sleeve 23 at a position opposite to the second plug connector 24 .

[0044] Furthermore, a first limiting ring groove is provided on the outer wall of the first metal shell 18, and a first sealing and pressure-resistant O-ring is sleeved in the first limiting ring groove; a second limiting ring groove is provided on the outer wall of the second metal shell 28, and a second sealing and pressure-resistant O-ring is sleeved in the second limiting ring groove, so as to realize rapid installation, fixation and pressure-resistant sealing of the connector.

[0045] Furthermore, the first plug connector 14 and the second plug connector 24 are gold-plated.

[0046] A first plug-in connector 14 is provided at the tail end of the female connector 1, and a second plug-in connector 24 is provided at the tail end of the male connector 2 to achieve quick plugging and unplugging; the connectors are gold-plated to improve conductivity, and can be used in conjunction with a five-core socket to achieve quick plugging and unplugging of the wellhead connector.

[0047] The present invention adopts a seven-stage high-temperature injection molding process, with the highest injection molding temperature reaching above 350°C, the injection molding pressure being controlled above 10MPa, and the injection molding time, holding time and cooling time being strictly carried out in accordance with the process requirements.

[0048] As described above, the downhole high-power AC / DC coaxial connector of the present invention has the following beneficial effects:

[0049] The present invention provides a downhole high-power AC / DC coaxial connector. Two DC conductive rings and three AC conductive rings are provided on both the male connector and the female connector, forming a five-core coaxial rotating plug-in structure, realizing the plug-in connection of a three-core AC power cable and a two-core DC cable, providing high-power power for downhole electric drilling tools, and at the same time providing power and DC carrier communication for various functional short sections downhole; each conductive ring of the female connector is insulated and protected by a first plastic insulating sleeve, and each conductive ring of the male connector is insulated and protected by a second plastic insulating sleeve. The entire connector is injection molded using a high-temperature integrated process, and has reliable strength and insulation performance, meeting the requirements of downhole drilling tools. The invention can realize the sealing of downhole high-pressure environment, insulation of high-voltage and high-current environment, multiple plugging and unplugging, and reliability in mud acid and alkali corrosion environment; the tails of the male connector and the female connector are respectively provided with corresponding plug-in connectors, which have the functions of self-cleaning, quick replacement and maintenance; the present invention realizes the small size of the downhole connector, the simultaneous transmission of high-power power electricity and DC carrier communication, the maximum transmission power reaches 70kW, it is resistant to high temperature and high pressure, and the DC carrier transmission efficiency is reliable, which effectively solves the real-time control and signal transmission problems of downhole electric drilling tools, and effectively solves the bottleneck problem of long-distance power transmission and signal transmission failure in continuous pipe drilling technology, and ensures the safe and smooth operation of the entire system.

[0050] The above description is only an illustrative embodiment of the present invention and is not intended to limit the scope of the present invention. Any equivalent changes and modifications made by those skilled in the art without departing from the concept and principle of the present invention shall fall within the scope of protection of the present invention.

Claims

1. A downhole high-power AC / DC coaxial connector, wherein: include: A female connector, comprising two first DC conductive rings and three first AC conductive rings arranged at insulating intervals along an axial direction, wherein each of the first DC conductive rings and each of the first AC conductive rings are connected as one through a first plastic insulating sleeve by injection molding, and the first end of the first plastic insulating sleeve is open; a first plug connector is arranged at the second end of the first plastic insulating sleeve, and the first plug connector and the first plastic insulating sleeve are connected as one through an integrated injection molding sleeve; two first DC sockets and three first AC sockets are arranged on the first plug connector, each of the first DC conductive rings is electrically connected to each of the first DC sockets, and each of the first AC conductive rings is electrically connected to each of the first AC sockets; A connector male connector can be coaxially plugged into the connector female connector, including a positioning rod, a conductive rod is sleeved on the positioning rod, two second DC conductive rings that can contact the first DC conductive ring and three second AC conductive rings that can contact the first AC conductive ring are arranged inwardly at the second end of the conductive rod, a second plug connector is arranged at the first end of the conductive rod, two second DC jacks and three second AC jacks are arranged on the second plug connector, each of the second DC conductive rings is electrically connected to each of the second DC jacks, and each of the second AC conductive rings is electrically connected to each of the second AC jacks; each of the second DC conductive rings, each of the second AC conductive rings and the conductive rod are connected as a whole by injection molding through a second plastic insulating sleeve.

2. The underground high-power AC / DC coaxial connector according to claim 1, wherein: Each of the second DC conductive rings and each of the second AC conductive rings includes a male connector ring body, a dovetail groove is provided on the outer wall of the male connector ring body, a finger contact spring is installed in the dovetail groove, and the finger contact spring is in electrical contact with each of the first DC conductive rings or each of the first AC conductive rings.

3. The underground high-power AC / DC coaxial connector according to claim 2, wherein: The male connector ring body is made of beryllium bronze material, and both the male connector ring body and the finger spring are gold-plated.

4. The underground high-power AC / DC coaxial connector according to claim 1, wherein: The second DC conductive ring and the second AC conductive ring are arranged at insulated intervals inward from the second end of the positioning rod, and each of the second DC conductive rings and each of the second AC conductive rings are arranged in a stepped manner with increasing diameters, and a male connector O-ring is arranged between two adjacent second DC conductive rings, between adjacent second DC conductive rings and second AC conductive rings, and between two adjacent second AC conductive rings.

5. The underground high-power AC / DC coaxial connector according to claim 1, wherein: Five second conductive support rods of different lengths are extended from the first end to the second end of the conductive rod, the first end of each of the second conductive support rods is electrically connected to the second DC socket or the second AC socket, and the second end of each of the second conductive support rods is electrically connected to the second DC conductive ring or the second AC conductive ring.

6. The underground high-power AC / DC coaxial connector according to claim 5, wherein: The second conductive support rod is in the form of a flat round rod.

7. The downhole high-power AC / DC coaxial connector according to claim 1, wherein: Vulcanized rubber layers are respectively provided at two axial ends of each of the first DC conductive rings and each of the first AC conductive rings.

8. The underground high-power AC / DC coaxial connector according to claim 1, wherein: A locking nut is arranged on the inner side of the first end of the first plastic insulating sleeve.

9. The underground high-power AC / DC coaxial connector according to claim 1, wherein: Five first conductive support rods of different lengths are extended on the first plug connector toward the first AC conductive ring, a first end of each of the first conductive support rods is electrically connected to the first DC socket or the first AC socket, and a second end of each of the first conductive support rods is electrically connected to the first DC conductive ring or the first AC conductive ring.

10. The underground high-power AC / DC coaxial connector according to claim 9, wherein: The first conductive support rod is arranged in the form of a flat rod.

11. The underground high-power AC / DC coaxial connector according to claim 1, wherein: Each of the first direct current conductive rings and each of the first alternating current conductive rings are made of beryllium copper material and are gold-plated.

12. The underground high-power AC / DC coaxial connector according to claim 1, wherein: A first metal shell is sleeved on the integrated injection-molded sleeve at a position opposite to the first plug connector; and a second metal shell is sleeved on the second plastic insulating sleeve at a position opposite to the second plug connector.

13. The downhole high-power AC / DC coaxial connector according to claim 12, wherein: A first limiting ring groove is arranged on the outer wall of the first metal shell, and a first sealing and pressure-resistant O-ring is sleeved in the first limiting ring groove; a second limiting ring groove is arranged on the outer wall of the second metal shell, and a second sealing and pressure-resistant O-ring is sleeved in the second limiting ring groove.

14. The underground high-power AC / DC coaxial connector according to claim 1, wherein: The first plug connector and the second plug connector are gold-plated.

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