A pressure balancing device and a method for opening a hole under pressure in a petroleum pipeline

Abstract

The invention relates to the technical field of pipeline pressure drilling, and discloses a pressure balancing device for plugging and sealing a hole under pressure in an oil pipeline, comprising a main pipeline, a drilling pipe fitting welded on the main pipeline, a weld seam welded at the welding point between the drilling pipe fitting and the main pipeline, a clamping plate valve connected to the top of the drilling pipe fitting through a flange, a drilling cylinder connected to the top of the clamping plate valve through a flange, a drilling machine arranged inside the drilling cylinder, and the clamping plate valve is opened, the drilling pipe fitting is connected to the inside of the drilling cylinder, a pressure balancing pipe is connected to the right side of the drilling cylinder, and the end of the pressure balancing pipe is connected to the inside of the main pipeline. The pressure balancing device for plugging and sealing a hole under pressure in an oil pipeline and a drilling method are provided, by arranging a pressure balancing device, connecting the drilling cylinder with the inside of the main pipeline through a pressure balancing pipe, and performing pressure balancing through a pressure balancing valve, thereby avoiding the strong impact of the high pressure in the oil pipeline on the drilling machine, and protecting the production safety and the safety of the operator.

Description

Technical Field

[0001] The invention relates to the technical field of pipeline pressure opening, in particular to a pressure balancing device for plugging pressure opening of a petroleum pipeline and a hole opening method. Background Art

[0002] The equipment of the non-stop drilling device under pressure is to drill holes without stopping production. The drilling machine is carried out in a completely closed cavity during the drilling process. The cutting process of the tool is isolated from the air, and there is no possibility of fire or explosion. Since the holes are closed and there is no leakage, toxic and harmful media cannot be discharged into the atmosphere, so there is no pollution to the environment. Pipeline pressure drilling is a safe, environmentally friendly, economical and efficient in-service pipeline transformation and emergency repair technology, which is suitable for normal maintenance and renovation of pipelines with various media such as water, crude oil, refined oil, chemical media, natural gas, etc. and emergency repair of emergencies.

[0003] In the past few years, a large number of petrochemical plants have been built and put into operation. The problem that comes with it is that after the operation cycle, the plant needs to be repaired, modified or defect-eliminating measures to maintain the operation of the plant for the next cycle. Once it involves maintenance and modification, the plant often needs to be shut down, and once it is shut down, a great loss of benefits will be incurred. Pressure drilling technology is an operation technology that uses mechanical cutting to process circular holes on pressure pipes. This technology uses a hole-drilling machine to drill holes in pressurized equipment and pipelines without stopping the plant. It does not affect the normal operation of the device, and can ensure the safe, efficient and environmentally friendly completion of pipeline joints or reserved interfaces.

[0004] The existing pressurized hole punching device punches holes in the pipeline under pressure. Since the pipeline is a flammable oil pipeline, the high pressure in the oil pipeline will have a strong impact on the puncher at the moment it opens the oil pipeline, and even cause an accident. Summary of the invention

[0005] 1. Technical issues to be solved

[0006] In view of the deficiencies in the prior art, the present invention provides a pressure balancing device for plugging and opening a hole under pressure in a petroleum pipeline and a hole opening method.

[0007] (II) Technical solution

[0008] To solve the above problems, the present invention provides the following technical solutions: a pressure balancing device for plugging and opening a hole under pressure in a petroleum pipeline, comprising a main pipeline, characterized in that: a perforated pipe fitting is welded on the main pipeline, a weld is welded at the welding point between the perforated pipe fitting and the main pipeline, a clamping valve is connected to the top of the perforated pipe fitting through a flange, a perforated cylinder is connected to the top of the clamping valve through a flange, a perforating machine is arranged inside the perforated cylinder, and when the clamping valve is opened, the perforated pipe fitting is connected to the inside of the perforated cylinder, a pressure balancing pipe is connected to the right side of the perforated cylinder, the end of the pressure balancing pipe is connected to the inside of the main pipeline, a second control valve is arranged at one end of the pressure balancing pipe close to the main pipeline, a first control valve is arranged at one end of the pressure balancing pipe close to the perforated cylinder, a pressure balancing valve and a secondary pressure gauge are arranged in sequence on the flow direction of the pressure balancing pipe from the main pipeline to the perforated cylinder, and an exhaust valve is arranged on the right side of the upper end of the perforated cylinder.

[0009] Preferably, the pressure balancing valve adopts a ZYC type self-operated pressure balancing valve.

[0010] Preferably, a main pressure gauge is provided on the main pipeline, and the main pressure gauge is used to detect the oil pressure inside the main pipeline.

[0011] Preferably, the upper end of the splint valve is connected to a right-angle tube via a flange, a corresponding "O" ring is placed at the connecting surface between the splint valve and the right-angle tube, and fixed installation is performed by tightening bolts, and the other end of the right-angle tube is fixedly connected to a fixed flange, and the fixed flange is fixedly connected to a branch pipeline.

[0012] Preferably, a method for opening a hole in a pressure balance device for plugging a hole under pressure in a petroleum pipeline comprises the following steps: S1: welding a hole-opening pipe fitting;

[0013] S2: Detect weld;

[0014] S3: Install the clamp valve;

[0015] S4: Install the hole opening machine;

[0016] S5: connecting the perforated tube with the interior of the main pipeline;

[0017] S6: Balance the pressure inside the perforated tube and the main pipeline;

[0018] S7: drilling holes in the main pipeline;

[0019] S8: dismantle the hole opening machine;

[0020] S9: Connect branch pipeline.

[0021] Preferably, when welding the perforated pipe fitting in step S1, the pressure inside the main pipeline that allows pressurized welding should first be detected and calculated to ensure the safety of the welding work:

[0022] Calculate the allowable pressure for pressure test welding of pipelines: the formula is as follows:

[0023]

[0024] Where:

[0025] P---The pressure allowed for pressurized welding of equipment and pipelines, in MPa;

[0026] σs---Minimum yield limit of equipment and pipeline parent materials, unit: MPa;

[0027] t---Actual thickness of pipes and equipment at welding point, unit: mm;

[0028] c---Wall thickness correction caused by welding, unit: mm;

[0029] D---Outer diameter of equipment and pipeline, unit: mm;

[0030] F---Safety factor (0.6 for non-flammable and toxic media such as water and nitrogen; 0.5 for toxic and flammable media);

[0031] The allowable pressure for test welding of pipeline under pressure is calculated according to the above formula, and then the internal pressure of the main pipeline is detected according to the main pressure gauge. When the internal pressure of the main pipeline is greater than the allowable pressure for test welding of pipeline under pressure, the welding conditions are not met and welding work cannot be performed. It is necessary to manually adjust the internal pressure of the main pipeline to make the internal pressure less than the allowable pressure for test welding of pipeline under pressure.

[0032] Preferably, the weld leak detection method in step S2 is leak detection with a helium mass spectrometer leak detector: it includes a cover plate, an exhaust pipe, a connecting flange and a helium mass spectrometer leak detector, the cover plate is fixedly connected to the upper port of the perforated pipe fitting by bolts, a corresponding "O" ring is placed at the interface between the perforated pipe fitting and the cover plate to ensure the sealing performance of the interface, an exhaust port is provided on the upper side of the cover plate, the exhaust port is connected to the exhaust pipe through a tooling, the end of the exhaust pipe is connected to a connecting flange, and the lower end of the connecting flange is connected to the exhaust port on the helium mass spectrometer leak detector.

[0033] Preferably, the helium mass spectrometer leak detector is a SFJ-261 helium mass spectrometer leak detector.

[0034] (III) Beneficial effects

[0035] Compared with the prior art, the present invention provides a pressure balancing device and a method for opening a hole under pressure in a petroleum pipeline, which has the following beneficial effects:

[0036] 1. The oil pipeline pressure-opening and plugging pressure balancing device and the opening method, by setting the pressure balancing device, connecting the opening cylinder with the inside of the main pipeline through the pressure balancing pipe, and balancing the pressure through the pressure balancing valve, avoids the strong impact of the high pressure in the oil pipeline on the punching machine, and protects the production safety and the safety of the operator.

[0037] 2. The pressure balancing device and the opening method for oil pipeline pressure opening and plugging can make welding work in a safe state by calculating the pressure allowed for the pipeline pressure test welding, avoid welding through, ensure the safety performance of the operation, and avoid safety accidents.

[0038] 3. The pressure balancing device and the method for opening a hole under pressure in the oil pipeline can detect the leak inside the hole fittings more accurately by using a helium mass spectrometer leak detector to detect the leak. This ensures that the hole fittings are in an absolutely sealed state, avoids leakage during long-term use, and improves the service life of the hole fittings. This solves the problem of low accuracy of traditional magnetic particle detection and leakage of the hole fittings after long-term use. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is a structural schematic diagram of a pressure balancing device for plugging a hole under pressure in a petroleum pipeline according to the present invention;

[0040] Figure 2 It is a schematic diagram of the structure of the helium mass spectrometer leak detector of the present invention;

[0041] Figure 3 It is a structural schematic diagram of the branch pipeline of the present invention;

[0042] Figure 4 It is a structural schematic diagram of the welding of the welding pipeline of the present invention.

[0043] In the figure: 1 main pipeline, 2 welding seam, 3 perforated pipe fittings, 4 main pressure gauge, 5 clamp valve, 6 perforated cylinder, 7 perforating machine, 8 first control valve, 9 auxiliary pressure gauge, 10 pressure balance valve, 11 pressure balance pipe, 12 second control valve, 13 cover plate, 14 exhaust pipe, 15 connecting flange, 16 helium mass spectrometer leak detector, 17 right angle pipe, 18 fixed flange, 19 branch pipeline, 20 exhaust valve. DETAILED DESCRIPTION

[0044] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only 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 ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0045] See also Figure 1-Figure 4 The present invention provides a new technical solution: a pressure balancing device for plugging and opening a hole in a petroleum pipeline under pressure, and a method for opening a hole, comprising a main pipeline 1, a hole-opening pipe fitting 3 is welded on the main pipeline 1, a weld 2 is welded at the welding point between the hole-opening pipe fitting 3 and the main pipeline 1, a clamping plate valve 5 is connected to the top of the hole-opening pipe fitting 3 through a flange, a hole-opening cylinder 6 is connected to the top of the clamping plate valve 5 through a flange, a hole-opening machine 7 is arranged inside the hole-opening cylinder 6, the clamping plate valve 5 is opened, the hole-opening pipe fitting 3 and the inside of the hole-opening cylinder 6 are connected, and the hole-opening pipe fitting 3 and the inside of the hole-opening cylinder 6 are connected. The right side of the perforated tube 6 is connected to a pressure balancing tube 11, the end of the pressure balancing tube 11 is connected to the interior of the main pipeline 1, a second control valve 12 is provided at one end of the pressure balancing tube 11 close to the main pipeline 1, a first control valve 8 is provided at one end of the pressure balancing tube 11 close to the perforated tube 6, a pressure balancing valve 10 and a secondary pressure gauge 9 are sequentially provided on the pressure balancing tube 11 in the flow direction from the main pipeline 1 to the perforated tube 6, and an exhaust valve 20 is provided on the right side of the upper end of the perforated tube 6.

[0046] In this embodiment, the pressure balancing valve 10 adopts a ZYC type self-operated pressure balancing valve; its working principle is as follows: (when the water supply pressure P1 increases or decreases, the signal is transmitted from the connecting pipe to the upper cavity of the diaphragm, driving the valve core to move down or up, so that the flow area of ​​the valve seat decreases or increases. P2-P3 also increases or decreases until P1-P2 remains constant at the original value. When the return water pressure P3 increases or decreases, the flow rate from the valve seat to the outlet decreases or increases, and the pressure P2 under the diaphragm also increases or decreases at this moment, driving the valve core to move up or down until the force on the diaphragm is rebalanced, P2 returns to its original value, and P1-P2 protects the original value constant, thereby ensuring that the pressure difference between the supply and return water of the controlled system remains basically unchanged). P1 refers to the oil pressure inside the pressure balancing tube 11 of the water inlet pipe of the pressure balancing valve 10, that is, the oil pressure inside the main pipeline 1; P2 refers to the oil pressure inside the pressure balancing tube 11 at the water outlet pipe of the pressure balancing valve 10, that is, the oil pressure inside the perforated tube 6; P3 refers to the oil pressure inside the return water pipe of the pressure balancing valve 10.

[0047] In this embodiment, a main pressure gauge 4 is provided on the main pipeline 1 , and the main pressure gauge 4 is used to detect the oil pressure inside the main pipeline 1 .

[0048] In this embodiment, the upper end of the clamp valve 5 is connected to the right-angle tube 17 via a flange, and a corresponding "O" ring is placed at the connection interface between the clamp valve 5 and the right-angle tube 17, and is fixedly installed by tightening bolts. The other end of the right-angle tube 17 is fixedly connected to a fixed flange plate 18, and the fixed flange plate 18 is fixedly connected to a branch pipeline 19.

[0049] See also Figure 1A method for opening a hole in a petroleum pipeline under pressure and sealing a pressure balance device, comprising the following steps:

[0050] S1: Welding the perforated pipe fitting 3; First, the surface of the part of the main pipeline 1 where the perforated pipe fitting 3 is to be welded needs to be polished and cleaned to remove any debris such as oil, rust, water, etc., and the metallic luster is visible; then the perforated pipe fitting 3 is fixed in the welding position, and then the perforated pipe fitting 3 is welded. The argon arc welding process is used for the base, and the single-sided welding and double-sided forming process is used. The root should be welded through, and the remaining layers are welded by manual arc welding. During the welding process, a small current should be used as much as possible to prevent burning through the mother pipe, and the perforated pipe fitting 3 is welded to the surface of the main pipeline 1.

[0051] S2: Detecting the weld 2; after the perforated pipe fitting 3 is welded, the weld 2 is leak-checked and the internal sealing performance of the perforated pipe fitting 3 is detected.

[0052] S3: Install the clamp valve 5; after the internal sealing test is qualified, the clamp valve 5 is connected to the upper end of the perforated pipe fitting 3 through a flange, and a corresponding "O" ring is placed at the connection interface between the perforated pipe fitting 3 and the clamp valve 5, and the installation is fixed by tightening bolts to ensure the sealing performance of the connection between the perforated pipe fitting 3 and the clamp valve 5.

[0053] S4: Install the hole-opening machine 7; the upper end of the clamp valve 5 is connected to the hole-opening cylinder 6 through a flange, and a corresponding "O" ring is placed at the connection interface between the clamp valve 5 and the hole-opening cylinder 6. The clamp valve 5 is fixed and installed by tightening bolts to ensure the sealing performance of the connection between the clamp valve 5 and the hole-opening cylinder 6, and then the hole-opening machine 7 is installed inside the hole-opening cylinder 6.

[0054] S5: connecting the perforated tube 6 with the interior of the main pipeline 1; first, a through hole is opened on the right side of the main pipeline 1 near the perforated pipe fitting 3 to connect the pressure balancing tube 11, the end of the pressure balancing tube 11 is connected with the interior of the perforated tube 6, a second control valve 12 is provided at one end of the pressure balancing tube 11 near the main pipeline 1, a first control valve 8 is provided at one end of the pressure balancing tube 11 near the perforated tube 6, and a pressure balancing valve 10 and a secondary pressure gauge 9 are sequentially provided on the pressure balancing tube 11 in the flow direction from the main pipeline 1 to the perforated tube 6.

[0055] S6: Balance the pressure inside the perforated tube 6 with that inside the main pipeline 1; first open the second control valve 12, the oil inside the main pipeline 1 flows into the pressure balancing valve 10 through the front end pressure balancing tube 11, and the pressure is balanced through the pressure balancing valve 10, and the pressure of the auxiliary pressure gauge 9 is observed. When the value of the auxiliary pressure gauge 9 is consistent with the value on the main pressure gauge 4, open the first control valve 8 and the exhaust valve 20, and the oil inside the pressure balancing tube 11 enters the perforated tube 6. Open the clamp valve 5, and the oil inside the pressure balancing tube 11 is stored in the perforated pipe fitting 3 and the perforated tube 6. The gas inside the perforated pipe fitting 3 and the perforated tube 6 is discharged through the exhaust valve 20. When the perforated tube 6 is full of oil, the gas inside the surface perforated tube 6 is completely discharged. Close the exhaust valve 20, observe the auxiliary pressure gauge 9, and when the value of the auxiliary pressure gauge 9 is the same as that of the main pressure gauge 4, the main pipeline 1 can be drilled.

[0056] S7: Drill a hole in the main pipeline 1; start the hole punching machine 7 to drill a hole on the surface of the main pipeline 1 inside the hole punching pipe fitting 3, rotate the hole punching machine 7 to drive the hole punching cutter to move downward, and the concentricity error between the hole punching cutter and the hole punching tube 6 meets the requirements. As the hole punching cutter starts to cut the wall of the main pipeline 1, the tool cutting noise can be heard. During the cutting process, the rotation speed is kept stable. After the hole cutting is completed, the cutting noise will decrease or stop, and the hole cutting work is completed. To confirm whether the hole drilling is completed, the tool only needs to be manually entered 5-6 times. If it can be entered smoothly, it indicates that the hole drilling has been completed. If it cannot be entered, it means that the hole drilling needs to be continued. After the hole drilling is completed, the tool is returned to the hole drilling tube 6.

[0057] S8: Disassemble the hole-opening machine 7; the tool is returned to the hole-opening cylinder 6, the clamp valve 5 is closed, and then the first control valve 8 and the second control valve 12 are closed in sequence, and then the pressure balance pipe 11 is disassembled from the main pipeline 1 and the through hole opened on the main pipeline 1 is blocked, and then the first control valve 8 and the second control valve 12 are opened, and the oil inside the hole-opening cylinder 6 will flow out through the pressure balance pipe 11 and be collected by the collecting tank, and the exhaust valve 20 is opened to make the oil inside the hole-opening cylinder 6 flow out more quickly, and then the connection between the upper end of the clamp valve 5 and the lower end of the hole-opening cylinder 6 is disassembled, thereby completing the disassembly of the hole-opening machine 7.

[0058] S9: Connect the branch pipeline 19; the upper end of the clamp valve 5 is connected with a right-angle pipe 17 through a flange, and a corresponding "O" ring is placed at the connection interface between the clamp valve 5 and the right-angle pipe 17, and fixed and installed by tightening bolts, and then the other end of the right-angle pipe 17 is fixedly connected with a fixed flange 18, which is fixedly connected to the branch pipeline 19 through the fixed flange 18, and finally the clamp valve 5 is opened, thereby achieving the purpose of opening a hole in the main pipeline to add a branch line.

[0059] In this embodiment, a pressure balancing device is provided to connect the perforating tube 6 with the interior of the main pipeline 1 through a pressure balancing pipe 11, and pressure balancing is performed through a pressure balancing valve 10, thereby avoiding the strong impact of the high pressure in the oil pipeline on the punching machine and protecting the production safety and the safety of the operator.

[0060] Embodiment 1

[0061] like Figure 4 As shown, in step S1, when welding the perforated pipe 3, the pressure inside the main pipeline 1 that allows pressurized welding must first be detected and calculated to ensure the safety of the welding work:

[0062] (1) Confirm the position of the welded perforated pipe fitting 3: Perform ultrasonic thickness measurement on the position of the perforated pipe fitting 3 on the main pipeline 1 to understand the corrosion condition inside the pipeline and select the position with less corrosion for welding.

[0063] (2) Calculate the allowable pressure for pressure test welding of pipelines: the formula is as follows:

[0064]

[0065] Where:

[0066] P---The pressure allowed for pressurized welding of equipment and pipelines, in MPa;

[0067] σs---Minimum yield limit of equipment and pipeline parent materials, unit: MPa;

[0068] t---Actual thickness of pipes and equipment at welding point, unit: mm;

[0069] c---Wall thickness correction caused by welding, unit: mm;

[0070] D---Outer diameter of equipment and pipeline, unit: mm;

[0071] F---Safety factor (0.6 for non-flammable and toxic media such as water and nitrogen; 0.5 for toxic and flammable media);

[0072] The allowable pressure for test welding of pipeline under pressure is calculated according to the above formula, and then the internal pressure of main pipeline 1 is detected according to main pressure gauge 4. When the internal pressure of main pipeline 1 is greater than the allowable pressure for test welding of pipeline under pressure, welding conditions are not met and welding work cannot be performed. It is necessary to manually adjust the internal pressure of main pipeline 1 so that the internal pressure is less than the allowable pressure for test welding of pipeline under pressure.

[0073] (3) Clean the welding area: clean any debris such as oil, rust, water, etc. within a range of no less than 10 mm on both sides of the weld to reveal the metallic luster.

[0074] (4) For the welding of open-hole pipe fittings, argon arc welding for base, manual welding for filling and blue surface welding are adopted. Before welding, the welding rod is dried at a temperature between 300℃ and 350℃ for 2 hours. After the welding rod is taken out of the drying box, it should be immediately placed in an insulation bucket and welding should be carried out immediately. The welding rod that has not been used up within 1 hour should be put back into the drying box for drying.

[0075] (5) In order to reduce the temperature of the inner wall of the pipeline at the welding site during welding, a small current spot welding method is used for the first welding. The arc starting time must be controlled within 10-30 seconds each time; the welding length cannot exceed 4cm. And the next arc starting can only be performed after an interval of 1 minute. In this way, the temperature after passing through the welding mother pipe will be brought to the medium in the pipeline in time, thereby ensuring the normal implementation of safe welding. After welding is completed, the next step of detection is carried out.

[0076] This embodiment calculates the pressure allowed for the pipeline to be tested under pressure, so that welding can be performed in a safe state, avoiding the phenomenon of weld penetration, ensuring the safety performance of the operation, and avoiding safety accidents.

[0077] Embodiment 2

[0078] like Figure 2 As shown, in the step S2, the weld leak detection method is a helium mass spectrometer leak detector leak detection: it includes a cover plate 13, an exhaust pipe 14, a connecting flange 15 and a helium mass spectrometer leak detector 16, the cover plate 13 is fixedly connected at the upper end of the perforated pipe fitting 3 by bolts, and a corresponding "O" ring is placed at the interface between the perforated pipe fitting 3 and the cover plate 13 to ensure the sealing performance of the interface, and an exhaust port is provided on the upper side of the cover plate 13, and the exhaust port is connected to the exhaust pipe 14 through a tooling, and the end of the exhaust pipe 14 is connected to the connecting flange 15, and the lower end of the connecting flange 15 is connected to the exhaust port on the helium mass spectrometer leak detector 16.

[0079] In this embodiment, the helium mass spectrometer leak detector 16 is a SFJ-261 type helium mass spectrometer leak detector; when leak detection is performed on the weld 2 on the perforated pipe 3, the upper end of the perforated pipe 3 is first fixedly installed with the cover plate 13 by bolts, and then the helium mass spectrometer leak detector 16 is connected to the inside of the perforated pipe 3 through the exhaust pipe 14 and the connecting flange 15, and then the helium mass spectrometer leak detector 16 is started, and the inside of the perforated pipe 3 is vacuumed through the exhaust pipe 14 to detect whether there is any leakage inside the perforated pipe 3. In case of leakage, the set value of the vacuum leak detection is set inside the helium mass spectrometer leak detector 16 to determine whether there is leakage inside the perforated pipe 3. If the detection is qualified, it indicates that the weld 2 is welded completely without leakage, and then the next step of opening the hole can be carried out; if the detection is unqualified, it indicates that there is leakage in the weld 2, and the staff is required to manually remove the leakage point from the weld 2 and repair it. After the repair is completed, the leak detection is carried out again until the qualified position is reached to ensure the sealing performance inside the perforated pipe 3.

[0080] In this embodiment, the helium mass spectrometer leak detector 16 is used to perform leak detection on the inside of the perforated pipe fitting 3, so as to more accurately detect the sealing of the welding of the perforated pipe fitting 3, ensure that the perforated pipe fitting 3 is in an absolutely sealed state, avoid leakage during long-term use, increase the service life of the perforated pipe fitting 3, and solve the problem of low accuracy of traditional magnetic particle detection and leakage of the perforated pipe fitting 3 after long-term use.

[0081] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A pressure balancing device for plugging a hole under pressure in a petroleum pipeline, comprising a main pipeline (1), characterized in that: A perforated pipe fitting (3) is welded to the main pipeline (1), a weld (2) is welded between the perforated pipe fitting (3) and the main pipeline (1), a clamping valve (5) is connected to the top of the perforated pipe fitting (3) via a flange, a perforated cylinder (6) is connected to the top of the clamping valve (5) via a flange, a perforated machine (7) is arranged inside the perforated cylinder (6), when the clamping valve (5) is opened, the perforated pipe fitting (3) is connected to the inside of the perforated cylinder (6), and a pressure balance pipe (11) is connected to the right side of the perforated cylinder (6). The end of the pressure balance pipe (11) is connected to the interior of the main pipeline (1); a second control valve (12) is provided at one end of the pressure balance pipe (11) close to the main pipeline (1); a first control valve (8) is provided at one end of the pressure balance pipe (11) close to the perforated cylinder (6); a pressure balance valve (10) and a secondary pressure gauge (9) are provided in sequence in the direction of flow from the main pipeline (1) to the perforated cylinder (6); and an exhaust valve (20) is provided on the right side of the upper end of the perforated cylinder (6).

2. The pressure balancing device for plugging and sealing a hole under pressure in a petroleum pipeline according to claim 1, characterized in that: The pressure balancing valve (10) is a ZYC type self-operated pressure balancing valve.

3. The pressure balancing device for plugging a hole under pressure in a petroleum pipeline according to claim 1, characterized in that: The main pipeline (1) is provided with a main pressure gauge (4), and the main pressure gauge (4) is used to detect the oil pressure inside the main pipeline (1).

4. The pressure balancing device for plugging a hole under pressure in a petroleum pipeline according to claim 1 is characterized in that: The upper end of the clamp valve (5) is connected to a right-angle pipe (17) via a flange, a corresponding "O" ring is placed at the connection interface between the clamp valve (5) and the right-angle pipe (17), and the clamp valve (5) and the right-angle pipe (17) are fixedly installed by tightening bolts, and the other end of the right-angle pipe (17) is fixedly connected to a fixed flange (18), and the fixed flange (18) is fixedly connected to a branch pipeline (19).

5. The method for opening a hole in a pressure balancing device for opening and plugging a hole under pressure in a petroleum pipeline according to claim 1, comprising the following steps: S1: Welding of perforated pipe fittings (3); S2: inspect the weld (2); S3: Install the clamp valve (5); S4: Installing a hole-opening machine (7); S5: connecting the perforated tube (6) with the interior of the main pipeline (1); S6: Balancing the pressure inside the perforated tube (6) and the main pipeline (1); S7: drilling a hole in the main pipeline (1); S8: disassembling the hole opening machine (7); S9: Connect the branch pipeline (19).

6. A method for opening a hole in a pressure balancing device for opening and plugging a hole under pressure in a petroleum pipeline according to claim 5, characterized in that: When welding the perforated pipe (3) in step S1, the pressure inside the main pipe (1) that allows welding under pressure must first be detected and calculated to ensure the safety of the welding work: Calculate the allowable pressure for pressure test welding of pipelines: the formula is as follows: Where: P---The pressure allowed for pressurized welding of equipment and pipelines, in MPa; σs---Minimum yield limit of equipment and pipeline parent materials, unit: MPa; t---Actual thickness of pipes and equipment at welding point, unit: mm; c---Wall thickness correction caused by welding, unit: mm; D---Outer diameter of equipment and pipeline, unit: mm; F---Safety factor (0.6 for non-flammable and toxic media such as water and nitrogen; 0.5 for toxic and flammable media); The pressure allowed for the pipeline test welding is calculated according to the above formula, and then the internal pressure of the main pipeline (1) is detected according to the main pressure gauge (4). When the internal pressure of the main pipeline (1) is greater than the pressure allowed for the pipeline test welding, the welding conditions are not met and the welding work cannot be carried out. It is necessary to manually adjust the internal pressure of the main pipeline (1) so that the internal pressure is less than the pressure allowed for the pipeline test welding.

7. The method for opening a hole in a pressure balancing device for opening and plugging a hole under pressure in a petroleum pipeline according to claim 5, characterized in that: The weld leak detection method in step S2 is leak detection using a helium mass spectrometer leak detector, comprising a cover plate (13), an exhaust pipe (14), a connecting flange (15) and a helium mass spectrometer leak detector (16); the cover plate (13) is fixedly connected to the upper end of the perforated pipe (3) by means of bolts; a corresponding "O" ring is placed at the interface between the perforated pipe (3) and the cover plate (13) to ensure the sealing performance of the interface; an exhaust port is arranged on the upper side of the cover plate (13); the exhaust port is connected to the exhaust pipe (14) via a tool; the end of the exhaust pipe (14) is connected to a connecting flange (15); the lower end of the connecting flange (15) is connected to the exhaust port on the helium mass spectrometer leak detector (16).

8. The method for opening a hole in a pressure balancing device for opening and plugging a hole under pressure in a petroleum pipeline according to claim 7, characterized in that: The helium mass spectrometer leak detector (16) is a SFJ-261 type helium mass spectrometer leak detector.

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