Intelligent anti-out-of-control anti-theft device for long-stop well

Abstract

The invention relates to the technical field of oil extraction, and discloses a long-stop well intelligent out-of-control-prevention anti-theft device which comprises a first four-way joint, the lower port of the first four-way joint is suitable for being fixed to a well mouth of a long-stop well, first well mouth gate valves are installed at the ports of the two sides of the first four-way joint, and a first teletransmission pressure gauge is detachably arranged on the side, away from the first four-way joint, of one of the first well mouth gate valves; a first anti-theft screwed plug is arranged on the side, away from the first four-way joint, of the other first wellhead gate valve, and after the first anti-theft screwed plug and the first teletransmission pressure gauge are detached, the sides, away from the first four-way joint, of the two first wellhead gate valves are both suitable for being connected with a cement fracturing truck. A second wellhead gate valve is arranged between the lower port of the second four-way joint and the upper port of the first four-way joint, at least one of the other ports of the second four-way joint is provided with a second anti-theft screwed plug, and the lower port of the second four-way joint is suitable for being communicated with an oil pumping pipe. The anti-theft device can achieve the anti-theft function and can also achieve the blowout prevention function.

Description

Technical Field

[0001] The present invention relates to the technical field of oil production, and in particular to an intelligent anti-loss-of-control and anti-theft device for long-stop wells. Background Art

[0002] Petroleum is a non-renewable resource. With nearly five decades of exploration and development in my country, limited resources have gradually decreased, resulting in a large number of long-term idle wells with low oil and gas reserves and no production. Related technology discloses an anti-theft device for the wellhead of an idle well, including an anti-theft valve, an anti-theft box, a base, and a magnetic anti-theft assembly. One end of the anti-theft valve is connected to the oil well flange structure, and the other end is provided with a four-way valve. Both ends of the anti-theft valve are provided with oil well anti-theft clamps, and the three ports of the four-way valve away from the anti-theft valve are provided with anti-theft slip assemblies. The anti-theft box is detachably connected to the base via a magnetic anti-theft assembly. An anti-theft cavity is formed between the anti-theft box and the base, and the anti-theft valve, oil well flange structure, and four-way valve are disposed in the anti-theft cavity.

[0003] The above-mentioned related technologies can prevent theft. However, due to crustal movement or plate movement, some long-stopped wells will produce gas or oil, which will spray out through the wellhead. The above-mentioned related technologies cannot prevent blowouts. Summary of the Invention

[0004] In view of this, the present invention provides an intelligent anti-loss-of-control and anti-theft device for long-stop wells to solve the problem of blowout in long-stop wells.

[0005] The present invention provides an intelligent anti-loss-of-control and anti-theft device for a long-term well stoppage, comprising: A first four-way valve, the lower end of which is suitable for being fixed at the wellhead of a long-stop well, with first wellhead gate valves installed on both sides of the first four-way valve, a first remote pressure gauge being detachably mounted on the side of one of the first wellhead gate valves remote from the first four-way valve, and a first anti-theft plug being mounted on the side of the other first wellhead gate valve remote from the first four-way valve, wherein after the first anti-theft plug and the first remote pressure gauge are removed, the sides of the two first wellhead gate valves remote from the first four-way valve are both suitable for connection to a cement fracturing truck; The second four-way valve has a second wellhead gate valve between its lower port and the upper port of the first four-way valve, at least one of the remaining ports of the second four-way valve is provided with a second anti-theft wire plug, and the lower port of the second four-way valve is suitable for communicating with the oil pumping pipe.

[0006] Beneficial effects: Due to crustal movement or plate movement, some long-stopped wells will produce gas or oil, which will spray out through the wellhead. By detachably providing a first remote pressure gauge on the side of one of the first wellhead gate valves away from the first four-way valve, the pressure of the oil casing can be monitored by the first remote pressure gauge. When the pressure in the well increases due to crustal movement or plate movement, the pressure in the oil casing will also increase. The first remote pressure gauge can remotely transmit the monitored pressure to the platform or supervisory personnel, and blowout prevention can be achieved through an early warning plan. For example, the staff will go to the site to remove the first anti-theft wire plug and the first remote pressure gauge and connect the two first wellhead gate valves away from the side of the first four-way valve to a fracturing cement truck. The fracturing cement truck inputs cement into the oil casing, and the cement flows upward through the pumping pipe to form a U-shaped closed loop. The cement solidifies to form a cement column, thereby preventing the blowout. A first anti-theft plug is provided on one of the first wellhead gate valves, away from the first four-way valve. The first anti-theft plug has anti-theft properties and can be eccentrically or shaped, allowing it to be opened only with a dedicated wrench. This prevents unauthorized personnel from damaging or removing the first anti-theft plug. A second anti-theft plug is provided on at least one of the remaining ports of the second four-way valve. The second anti-theft plug has anti-theft properties and can be eccentrically or shaped, allowing it to be opened only with a dedicated wrench. This prevents unauthorized personnel from damaging or removing the second anti-theft plug. Therefore, this intelligent anti-loss and anti-theft device for long-term well stoppage can achieve both anti-theft and anti-blowout functions.

[0007] In an optional embodiment, a hanger is provided in the first cross-connection, and the hanger is connected to the oil pumping pipe.

[0008] Beneficial effect: The hanger is connected to the oil pumping pipe, and the top of the oil pumping pipe can be fixed.

[0009] In an optional embodiment, the lower port of the first cross-connection is suitable for connection with the lower flange at the wellhead via a flange anti-theft device.

[0010] Beneficial effect: The lower port of the first cross-piece is suitable for connection with the lower flange at the wellhead through the flange anti-theft device, which can prevent criminals from removing the first cross-piece from the wellhead.

[0011] In an optional embodiment, a first gauge bushing assembly is provided on a side of one of the first wellhead gate valves away from the first four-way valve, and a first threaded gate valve is provided between the first gauge bushing assembly and the first remote pressure gauge.

[0012] Beneficial effects: the provision of the first gauge bushing assembly facilitates the connection of the first remote pressure gauge, and the provision of the first threaded gate valve facilitates the disassembly of the first remote pressure gauge.

[0013] In an optional embodiment, the first wellhead gate valve and / or the second wellhead gate valve is provided with a magnetic lock.

[0014] Beneficial effect: The magnetic lock can only be opened by a specific magnetic key. For criminals, it is difficult to open the magnetic lock without a professional magnetic key. By arranging a magnetic lock on the first wellhead gate valve and / or the second wellhead gate valve, the anti-theft performance can be further improved.

[0015] In an optional embodiment, the first wellhead gate valve and / or the second wellhead gate valve is provided with a remote vibration alarm device.

[0016] Beneficial effect: By arranging a remote vibration alarm device on the first wellhead gate valve and / or the second wellhead gate valve, when an illegal person illegally damages the first wellhead gate valve and the second wellhead gate valve to cause vibration, the remote vibration alarm device will transmit a signal to the platform or supervisory personnel, thereby further preventing theft.

[0017] In an optional embodiment, an upper flange is provided at the lower end of the second wellhead gate valve, and the upper flange is connected to the upper end of the first four-way valve via a flange anti-theft device.

[0018] Beneficial effect: The upper flange is connected to the upper end of the first cross-piece through the flange anti-theft device, which can prevent criminals from removing the upper flange from the first cross-piece.

[0019] In an optional embodiment, anti-theft slip assemblies are provided at both side ports of the first four-way valve, the four ports of the second four-way valve, and the connection between the second wellhead gate valve and the upper flange.

[0020] Beneficial effect: By providing anti-theft slip components at both side ports of the first four-way valve, the four ports of the second four-way valve, and the connection between the second wellhead gate valve and the upper flange, the anti-theft performance can be further improved.

[0021] In an optional embodiment, a clamp head is provided at one end of the second anti-theft screw plug close to the second cross-piece, and the clamp head is connected to the second cross-piece.

[0022] Beneficial effect: a clamp head is provided at the second anti-theft thread plug, and the clamp head can be removed only by using specific equipment, which can further improve the anti-theft performance of the second anti-theft thread plug.

[0023] In an optional embodiment, a second remote pressure gauge is provided at at least one port of the second four-way valve, and a second threaded gate valve and a second gauge bushing assembly are further provided between the second remote pressure gauge and the second four-way valve.

[0024] Beneficial effects: The second remote pressure gauge can monitor the pressure of the oil pumping pipe and transmit the monitored pressure to the platform or supervisors. When the pressure of the oil pumping pipe is high, it is convenient for early warning. The second threaded gate valve and the second gauge bushing assembly are convenient for the installation and disassembly of the second remote pressure gauge. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0026] Figure 1 Schematic diagram of an intelligent anti-loss-of-control and anti-theft device for a long-stop well according to an embodiment of the present invention; Figure 2 This is a cross-sectional view of the first bushing assembly.

[0027] Description of reference numerals: 1. First four-way valve; 2. First wellhead gate valve; 3. First remote pressure gauge; 4. First anti-theft plug; 5. Second four-way valve; 6. Second wellhead gate valve; 7. Second anti-theft plug; 8. Pumping pipe; 9. Hanger; 10. Flange anti-theft device; 11. First gauge bushing assembly; 12. First threaded gate valve; 13. Upper flange; 14. Anti-theft slip assembly; 15. Second remote pressure gauge; 16. Second gauge bushing assembly; 17. Second threaded gate valve. DETAILED DESCRIPTION

[0028] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative efforts shall fall within the scope of protection of the present invention.

[0029] Petroleum is a non-renewable resource. With nearly five decades of exploration and development in my country, limited resources have gradually decreased, resulting in a large number of long-term idle wells with low oil and gas reserves and no production. Related technology discloses an anti-theft device for the wellhead of an idle well, including an anti-theft valve, an anti-theft box, a base, and a magnetic anti-theft assembly. One end of the anti-theft valve is connected to the oil well flange structure, and the other end is provided with a four-way valve. Both ends of the anti-theft valve are provided with oil well anti-theft clamps, and the three ports of the four-way valve away from the anti-theft valve are provided with anti-theft slip assemblies. The anti-theft box is detachably connected to the base via a magnetic anti-theft assembly. An anti-theft cavity is formed between the anti-theft box and the base, and the anti-theft valve, oil well flange structure, and four-way valve are disposed in the anti-theft cavity.

[0030] The above-mentioned related technologies can prevent theft. However, due to crustal movement or plate movement, some long-stopped wells will produce gas or oil, which will spray out through the wellhead. The above-mentioned related technologies cannot prevent blowouts.

[0031] The following combination Figure 1 , describing embodiments of the present invention.

[0032] According to an embodiment of the present invention, an intelligent anti-loss-of-control and anti-theft device for a long-stop well is provided, comprising: a first four-way valve 1 and a second four-way valve 5.

[0033] Among them, the lower port of the first four-way valve 1 is suitable for being fixed at the wellhead of a long-stop well, and the first wellhead gate valves 2 are installed on both side ports of the first four-way valve 1, wherein one of the first wellhead gate valves 2 is detachably provided with a first remote pressure gauge 3 on the side away from the first four-way valve 1, and the other first wellhead gate valve 2 is provided with a first anti-theft wire plug 4 on the side away from the first four-way valve 1. After the first anti-theft wire plug 4 and the first remote pressure gauge 3 are disassembled, the sides of the two first wellhead gate valves 2 away from the first four-way valve 1 are suitable for connecting to a cement fracturing truck; a second wellhead gate valve 6 is provided between the lower port of the second four-way valve 5 and the upper port of the first four-way valve 1, and at least one of the remaining ports of the second four-way valve 5 is provided with a second anti-theft wire plug 7, and the lower port of the second four-way valve 5 is suitable for connecting to a pumping pipe 8.

[0034] Due to crustal movement or plate movement, some long-stopped wells will also produce gas or oil, which will spray out through the wellhead. By detachably providing a first remote pressure gauge 3 on the side of one of the first wellhead gate valves 2 away from the first four-way valve 1, the pressure of the oil casing can be monitored by the first remote pressure gauge 3. When the pressure in the well increases due to crustal movement or plate movement, the pressure in the oil casing will also increase. The first remote pressure gauge 3 can remotely transmit the monitored pressure to the platform or supervisory personnel, and blowout prevention can be achieved through an early warning plan. For example, the staff will go to the site to remove the first anti-theft wire plug 4 and the first remote pressure gauge 3 and connect the two first wellhead gate valves 2 away from the side of the first four-way valve 1 to a fracturing cement truck. The fracturing cement truck inputs cement into the oil casing, and the cement flows upward through the pumping pipe 8 to form a U-shaped closed loop. The cement solidifies to form a cement column, thereby preventing the blowout. By providing a first anti-theft plug 4 on one of the first wellhead gate valves 2, away from the first four-way valve 1, the first anti-theft plug 4 has anti-theft properties, can be set eccentrically or set in a special-shaped structure, so that it can only be opened with a special wrench, which can prevent illegal personnel from damaging and removing the first anti-theft plug 4. By providing a second anti-theft plug 7 on at least one of the remaining ports of the second four-way valve 5, the second anti-theft plug 7 has anti-theft properties, can be set eccentrically or set in a special-shaped structure, so that it can only be opened with a special wrench, which can prevent illegal personnel from damaging and removing the second anti-theft plug 7. Therefore, this long-stop well intelligent anti-loss and anti-theft device can achieve both anti-theft and anti-blowout functions.

[0035] Specifically, when the pressure obtained by the first remote pressure gauge 3 exceeds the preset pressure, the first anti-theft wire plug 4 and the first remote pressure gauge 3 are removed and the two first wellhead gate valves 2 are connected to the side away from the first four-way valve 1 to the fracturing cement truck. The fracturing cement truck inputs cement into the oil casing, and the cement flows upward through the pumping pipe 8 to form a U-shaped closed loop, and the cement solidifies to form a cement column.

[0036] Specifically, the first four-way valve 1 is a large four-way valve, and the second four-way valve 5 is a small four-way valve.

[0037] In one embodiment, a hanger 9 is provided in the first spool 1 , and the hanger 9 is connected to the oil pumping pipe 8 .

[0038] In this embodiment, the hanger 9 is connected to the oil pumping pipe 8 and can fix the top of the oil pumping pipe 8.

[0039] In one embodiment, the lower port of the first cross-connection 1 is adapted to be connected to the lower flange at the wellhead via a flange anti-theft device 10 .

[0040] In this embodiment, the lower end of the first spool 1 is adapted to be connected to the lower flange at the wellhead via a flange anti-theft device 10 , thereby preventing criminals from removing the first spool 1 from the wellhead.

[0041] The flange anti-theft device 10 specifically includes an anti-theft fastener, which can be a fastener that can only be disassembled and installed using a specific opening tool, or a fastener that can only be installed in the forward direction and cannot be disassembled in the reverse direction. The anti-theft fastener can specifically be a conventional anti-theft bolt or a magnetic anti-theft bolt.

[0042] In one embodiment, a first gauge bushing assembly 11 is provided on a side of one of the first wellhead gate valves 2 away from the first four-way valve 1 , and a first threaded gate valve 12 is provided between the first gauge bushing assembly 11 and the first remote pressure gauge 3 .

[0043] In this embodiment, the provision of the first gauge bushing assembly 11 facilitates the connection of the first remote pressure gauge 3 , and the provision of the first threaded gate valve 12 facilitates the disassembly of the first remote pressure gauge 3 .

[0044] Specific as Figure 2 As shown, the first bushing assembly 11 is provided with an external thread on one side close to the first wellhead gate valve 2 , and the first bushing assembly 11 is provided with an internal thread on one side close to the first threaded gate valve 12 .

[0045] In one embodiment, the first wellhead gate valve 2 and / or the second wellhead gate valve 6 are provided with a magnetic lock.

[0046] In this embodiment, the magnetic lock can only be opened by a specific magnetic key. For criminals, it is difficult to open the magnetic lock without a professional magnetic key. By providing a magnetic lock on the first wellhead gate valve 2 and / or the second wellhead gate valve 6, the anti-theft performance can be further improved.

[0047] It should be noted that the magnetic lock is locked by using different positions of the magnetic core and can only be opened using a magnetic key with a specific number of magnetic points. Compared with conventional locks, it does not generate static electricity and does not produce sparks when opened, eliminating the possibility of ignition and explosion, and ensuring the safety of application in oil field environments.

[0048] Specifically in one embodiment, both the first wellhead gate valve 2 and the second wellhead gate valve 6 are provided with magnetic locks.

[0049] Specifically in one embodiment, the first wellhead gate valve 2 and the second wellhead gate valve 6 both include hand wheels, and the hand wheels are equipped with magnetic locks.

[0050] In one embodiment, the first wellhead gate valve 2 and / or the second wellhead gate valve 6 is provided with a remote vibration alarm device.

[0051] In this embodiment, by providing a remote vibration alarm device on the first wellhead gate valve 2 and / or the second wellhead gate valve 6, when an illegal person illegally damages the first wellhead gate valve 2 and the second wellhead gate valve 6 to cause vibration, the remote vibration alarm device will transmit a signal to the platform or supervisory personnel, thereby further preventing theft.

[0052] It should be noted that the remote vibration alarm device can detect low-decibel vibrations.

[0053] In one embodiment, an upper flange 13 is provided at the lower end of the second wellhead gate valve 6 , and the upper flange 13 is connected to the upper end of the first cross-way valve 1 via a flange anti-theft device 10 .

[0054] In this embodiment, the upper flange 13 is connected to the upper end of the first cross-piece 1 via the flange anti-theft device 10 , which can prevent criminals from removing the upper flange 13 from the first cross-piece 1 .

[0055] In one embodiment, anti-theft slip assemblies 14 are provided at both side ports of the first four-way port 1 , the four ports of the second four-way port 5 , and the connection between the third wellhead gate valve and the upper flange 13 .

[0056] In this embodiment, anti-theft performance can be further improved by providing anti-theft slip assemblies 14 at both side ports of the first four-way valve 1, the four ports of the second four-way valve 5, and the connection between the second wellhead gate valve 6 and the upper flange 13.

[0057] Specifically, the anti-theft slip assembly 14 can be composed of two hoops that enclose or circle the corresponding pipeline or equipment. The two ends of the hoops are connected by anti-theft fasteners. This ensures that the anti-theft slip assembly 14 can prevent the theft of the corresponding equipment while preventing it from being easily removed and can only be opened with a specific opening tool. The anti-theft fastener can be an anti-theft fastener that can only be removed and installed with a specific opening tool, or an anti-theft fastener that can only be installed in the forward direction and cannot be removed in the reverse direction.

[0058] In one embodiment, a clamp head is provided at one end of the second anti-theft screw plug 7 close to the second cross-piece 5 , and the clamp head is connected to the second cross-piece 5 .

[0059] In this embodiment, a clamp head is provided at the second anti-theft thread plug 7 , and the clamp head can be removed only by using specific equipment, which can further improve the anti-theft performance of the second anti-theft thread plug 7 .

[0060] In one embodiment, a second remote pressure gauge 15 is provided at at least one port of the second cross-connection 5 , and a second threaded gate valve 17 and a second gauge bushing assembly 16 are further provided between the second remote pressure gauge 15 and the second cross-connection 5 .

[0061] In this embodiment, the second remote pressure gauge 15 can monitor the pressure of the oil extraction pipe 8 and transmit the monitored pressure to the platform or supervisory personnel. When the pressure of the oil extraction pipe 8 is high, it is convenient to provide early warning. The second threaded gate valve 17 and the second gauge bushing assembly 16 facilitate the installation and removal of the second remote pressure gauge 15.

[0062] Specifically, the structure of the second bushing assembly 16 is the same as that of the first bushing assembly 11 . An end of the second bushing assembly 16 close to the second cross-connection 5 is provided with an external thread, and an end of the second bushing assembly 16 close to the second threaded gate valve 17 is provided with an internal thread.

[0063] In an embodiment not shown in the figure, the long-stop well intelligent anti-loss-of-control and anti-theft device can also include an anti-theft box, which is connected to the base through a magnetic anti-theft component to form an anti-theft cavity. The first four-way 1, the second four-way 5 and the various components in the above embodiments are all arranged in the anti-theft cavity. It is difficult for criminals to damage or dismantle the anti-theft box, and thus they cannot attack the valve-pipe equipment inside it, thereby improving the anti-theft performance.

[0064] Although the embodiments of the present invention have been described with reference to the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by this application.

Claims

1. An intelligent anti-loss-of-control and anti-theft device for long-term well stoppage, characterized in that: include: The first four-way valve (1) has a lower port suitable for being fixed at the wellhead of a long-stop well. Both sides of the first four-way valve (1) are equipped with first wellhead gate valves (2). One of the first wellhead gate valves (2) is detachably provided with a first remote pressure gauge (3) on a side away from the first four-way valve (1). The first remote pressure gauge (3) is used to monitor the pressure of the oil casing. The other first wellhead gate valve (2) is provided with a first anti-theft plug (4) on a side away from the first four-way valve (1). After the first anti-theft plug (4) and the first remote pressure gauge (3) are disassembled, the two The side of the first wellhead gate valve (2) away from the first four-way valve (1) is suitable for connecting to a cement fracturing truck, wherein a first gauge core assembly (11) is provided on the side of the first wellhead gate valve (2) away from the first four-way valve (1), a first threaded gate valve (12) is provided between the first gauge core assembly (11) and the first remote pressure gauge (3), an external thread is provided on the side of the first gauge core assembly (11) close to the first wellhead gate valve (2), and an internal thread is provided on the side of the first gauge core assembly (11) close to the first threaded gate valve (12); A second wellhead gate valve (6) is provided between the lower port of the second four-way valve (5) and the upper port of the first four-way valve (1); at least one of the remaining ports of the second four-way valve (5) is provided with a second anti-theft screw plug (7); the lower port of the second four-way valve (5) is suitable for communicating with the oil pumping pipe (8); a second remote pressure gauge (15) is provided at at least one port of the second four-way valve (5); a second threaded gate valve (17) and a second gauge bushing assembly (16) are provided between the second remote pressure gauge (15) and the second four-way valve (5); an end of the second gauge bushing assembly (16) close to the second four-way valve (5) is provided with an external thread; an end of the second gauge bushing assembly (16) close to the second threaded gate valve (17) is provided with an internal thread; two side ports of the first four-way valve (1) and four ports of the second four-way valve (5) are provided with anti-theft slip assemblies (14); the anti-theft slip assemblies (14) are composed of two hoops, and both ends of the two hoops are connected by anti-theft fasteners.

2. The intelligent anti-loss-of-control and anti-theft device for long-term well stoppage according to claim 1 is characterized in that: A hanger (9) is provided in the first cross-connect (1), and the hanger (9) is connected to the oil pumping pipe (8).

3. The intelligent anti-loss-of-control and anti-theft device for long-term well stoppage according to claim 1 is characterized in that: The lower port of the first cross-connection (1) is suitable for connection with the lower flange at the wellhead via a flange anti-theft device (10).

4. The intelligent anti-loss-of-control and anti-theft device for a long-term well stoppage according to any one of claims 1 to 3, characterized in that: The first wellhead gate valve (2) and / or the second wellhead gate valve (6) are provided with a magnetic lock.

5. The intelligent anti-loss-of-control and anti-theft device for long-term well stoppage according to claim 4 is characterized in that: The first wellhead gate valve (2) and / or the second wellhead gate valve (6) are provided with a remote vibration alarm device.

6. The intelligent anti-loss-of-control and anti-theft device for a long-term well stoppage according to any one of claims 1 to 3, characterized in that: An upper flange (13) is provided at the lower end of the second wellhead gate valve (6), and the upper flange (13) is connected to the upper end of the first four-way valve (1) via a flange anti-theft device (10).

7. The intelligent anti-loss-of-control and anti-theft device for long-term well stoppage according to claim 6 is characterized in that: An anti-theft slip assembly (14) is provided at the connection between the second wellhead gate valve (6) and the upper flange (13).

8. The intelligent anti-loss-of-control and anti-theft device for a long-term well stoppage according to any one of claims 1 to 3, characterized in that: The second anti-theft screw plug (7) is provided with a clamp head at one end close to the second cross-connection (5), and the clamp head is connected to the second cross-connection (5).

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