A method for oil / gas pipeline reconstruction

Abstract

This invention discloses a construction method for modifying oil / gas pipelines. One end of the oil / gas pipeline has an interface for welding a double-bend pipe, which includes a first section, a second section, and a third section. First, an airbag is used to seal the interface of the oil / gas pipeline. Then, the first section is welded to the interface. After the first section is welded to the interface, a drag-reducing support is inserted from the third section and movably positioned within the second bend. The drag-reducing support causes the airbag to deform inwards, allowing it to be removed from the opening of the third section. This invention enables hot work welding of oil / gas pipelines, facilitates the removal of the airbag temporarily sealing the pipeline, and ensures the integrity of the pipeline structure. It improves construction efficiency and reduces operational risks, while lowering economic, labor, and time costs, demonstrating broad application prospects.

Description

Technical Field

[0001] This invention relates to the field of oil / gas pipeline modification, and specifically to a construction method for modifying oil / gas pipelines containing oil and gas. Background Technology

[0002] With the rapid development of oil and gas pipelines in my country, it is often necessary to modify oil / gas pipelines. Specific modification methods include: rerouting oil / gas pipelines, adding branches, and cutting off and connecting pipelines during emergency rescue operations. Although the valves of the oil / gas pipelines are closed during these operations, oil and gas often remain inside the pipelines. When modifying them, it is often necessary to cut or weld the pipelines. If the concentration of oil and gas is high, an explosion accident is extremely likely to occur. Therefore, when modifying oil / gas pipelines, it is necessary to temporarily isolate and seal the pipeline joints before hot work and welding operations can be carried out.

[0003] The most commonly used technology in the current field is airbag isolation technology. This technology uses airbags to seal oil / gas pipelines. Specifically, an inflatable rubber airbag is inserted into the pipeline section where hot work is required. The airbag forms a sealed isolation layer for the oil and gas in the pipeline, reducing the construction risks associated with oil / gas pipelines. After construction is completed, the gas in the airbag is released, and the airbag is removed from the pipeline.

[0004] However, when modifying oil / gas pipelines, the pipes that need to be fixedly connected (usually by welding) on ​​the oil / gas pipelines are often different types of pipes, such as straight pipes, tees, bends, double-bend pipes (Z-shaped pipes), etc.; among them, double-bend pipes are more special.

[0005] A double-bend pipe consists of two right-angle welded elbows, with the two elbows bending in opposite directions by 180 degrees. When welding operations are required on oil / gas pipelines, airbags with a certain pressure-bearing capacity must be selected to ensure construction safety. However, airbags with pressure-bearing capacity usually have a small amount of deformation. When such airbags are pulled out of the double-bend pipe, they are prone to getting stuck at the bend of the double-bend pipe furthest from the weld, making it difficult to remove the airbag from the oil / gas pipeline.

[0006] Existing technologies include a construction method that involves pre-opening an airbag removal port on the pipeline near the airbag to remove it. However, this method affects the pipeline's structure, reduces its pressure resistance, and requires additional flange blind plates to be installed at the extra opening, which can easily lead to oil leaks during pipeline operation, affecting the overall service life and quality of the pipeline.

[0007] Therefore, a construction method is needed to make it easy to remove the airbags that temporarily seal the oil / gas pipeline without damaging the pipeline's structure and ensuring the integrity of the pipeline's structure. Summary of the Invention

[0008] The purpose of this invention is to provide a construction method for modifying oil / gas pipelines, in order to solve the technical problem that when double-bend pipes need to be welded on oil / gas pipelines, the pressure-bearing airbag is easily stuck at the bend of the double-bend pipe, making it difficult to remove the airbag from the oil / gas pipeline.

[0009] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0010] A method for modifying an oil / gas pipeline, wherein one end of the oil / gas pipeline has an interface for welding a double-bend pipe, the double-bend pipe comprising a first pipe section, a second pipe section, and a third pipe section; the first pipe section is used for welding to the interface; the second pipe section is perpendicular to the pipe extension directions of the first and third pipe sections respectively, and the pipe extension directions of the first and third pipe sections are parallel; the first and second pipe sections are connected by a first bend section close to the interface; the second and third pipe sections are connected by a second bend section; the clockwise and counterclockwise bending directions of the first and second bend sections are opposite.

[0011] First, an airbag with positive pressure bearing capacity is used to temporarily isolate and seal the oil and gas in the oil / gas pipeline at the interface. Then, the first pipe section is welded at the interface. After the first pipe section is welded to the interface, a drag-reducing support is inserted from the third pipe section and movably placed in the second bend. The drag-reducing support can cause the airbag to deform inward and reduce the frictional resistance when the airbag is dragged in the pipeline. Then, the drag-reducing support is removed and the airbag is pulled out from the pipe opening of the third pipe section, completing the modification construction of the oil / gas pipeline.

[0012] Preferably, the airbag includes a cylindrical body and an end cap. The cylindrical body is cylindrical, and the end cap is a hemispherical or elliptical end cap, which is fixedly connected to the cylindrical body. One of the end caps of the airbag has a vent and a traction ring on its outer surface. An outgoing inflation / deflation valve is installed on the vent, which is used to connect to a vent pipe. A traction hole is provided on the traction ring, which is used to fix a traction rope.

[0013] Preferably, the drag-reducing support includes an extension rod and a drag-reducing end fixedly connected to one end of the extension rod. The other end of the extension rod is located outside the third pipe section. The extension rod can be pushed by an external force and drive the drag-reducing end to apply force to the airbag, causing the airbag to deform inward, reducing the air pressure inside the airbag and reducing the volume of the airbag. When the airbag deforms inward, the airbag can move along the third pipe section to the outside of the pipe under the pulling action of the external force.

[0014] In one embodiment of the drag-reducing support structure, the drag-reducing end is a drag-reducing ball, and one end of the drag-reducing ball is fixedly connected to the drag-reducing ball. The end of the first extension rod away from the drag-reducing ball extends outside the double-bend pipe. The drag-reducing ball abuts against the airbag wall. When the first extension rod is pushed by an external force, it can transmit force to the drag-reducing ball, thereby causing the airbag to deform inward, reducing the airbag volume, and at the same time changing the direction of the airbag's traction force. While keeping the position of the first extension rod unchanged, the airbag is pulled out of the pipe.

[0015] In a second embodiment of the drag-reducing support structure, the drag-reducing end is a crossbar, with one end of a second extension rod fixedly connected to it. The end furthest from the crossbar extends beyond the double-bend pipe. The crossbar abuts against the airbag wall. When the second extension rod is pushed by an external force, it transmits force to the crossbar, causing the airbag to deform inwards, reducing its volume and changing the direction of the traction force. Keeping the second extension rod in place, the traction rope is then pulled, pulling the airbag out of the pipe. Compared to the drag-reducing ball, the crossbar reduces the contact area between the airbag wall and the bend in the second bend, resulting in less frictional resistance as the airbag moves through the double-bend pipe, further reducing the resistance when the airbag is pulled out.

[0016] In the third embodiment of the drag-reducing support structure, the drag-reducing end is a roller, with roller shafts fixedly connected to both ends of the roller. Each roller shaft is rotatably connected to a third extension rod. The end of the third extension rod away from the roller extends beyond the double-bend pipe. The roller abuts against the airbag wall. When the third extension rod is pushed by an external force, it can transmit force to the roller, thereby causing the airbag to deform inward, reducing the airbag volume, and simultaneously reducing the frictional resistance at the contact point between the airbag and the bend. Keeping the roller shaft position unchanged, the traction rope is then pulled to pull the airbag out of the pipe. Compared to the crossbar, the roller not only increases the contact area with the airbag wall and reduces the contact area between the airbag wall and the bend, but also allows the airbag wall to roll on the roller when in contact with it, further reducing the resistance encountered when pulling the airbag. It can also change the direction of the pulling force on the airbag, making it easier to pull out.

[0017] As a fourth embodiment of the drag-reducing support structure, the drag-reducing end can also be a grooved plate. One end of a fourth extension rod is fixedly connected to one side of the grooved plate. The grooved plate has an arcuate groove, and the center line of the bottom of the grooved plate is perpendicular to the extension direction of the fourth extension rod. On the side of the grooved plate away from the fourth extension rod, there is a protruding and laterally extending end. The end is cylindrical, and the extension direction is parallel to the center line of the bottom of the grooved plate. The end of the fourth extension rod away from the grooved plate extends beyond the double-bend pipe. The end first abuts against the airbag wall. When the fourth extension rod is pushed by an external force, it can transmit force to the end, thereby causing the airbag to undergo inward deformation. Then, the airbag wall at the remaining position on the inwardly deformed side is convex relative to the inwardly deformed part. The convex part enters the grooved plate, and the grooved plate has a locking effect on the inwardly deformed airbag. Then, the traction rope and the fourth extension rod are pulled at the same time. At this time, the components that simultaneously generate pulling force on the airbag are the traction rope and the grooved plate. The combination of the two can pull the airbag and the drag-reducing support out of the pipe at the same time. Compared to the above-mentioned drag-reducing support structures, the airbag wall with the grooved plate has the advantages of being able to apply force to deform the airbag and at the same time assisting the traction rope in pulling the airbag, which can further reduce the difficulty of pulling the airbag out from the second bend.

[0018] Preferably, before the airbag is installed in the oil-gas pipeline, grease is applied to the outer periphery of the uninflated airbag to enhance the airtightness between the airbag surface and the pipeline wall, and to reduce the frictional resistance between the airbag and the pipeline wall when the airbag is pulled in the pipeline. Then the airbag is inflated. When the airbag is inflated to a certain pressure, the outlet inflation / deflation valve is closed, and grease is filled at the airbag vent to form a grease isolation wall to prevent the oil and gas in the oil-gas pipeline from flowing to the pipeline welding area.

[0019] Preferably, grease is applied to the drag-reducing end of the extension rod to reduce the frictional resistance when the airbag passes through the second bend.

[0020] Preferably, lubricating oil is applied to the inner walls of the first and second bends of the double-bend pipe to reduce the frictional resistance as the airbag moves along the pipe.

[0021] This invention has the following beneficial effects: It can be applied to the modification of oil and gas pipelines, such as rerouting oil / gas pipelines, adding branches, and pipeline cutting and connection work during accident rescue; it can solve the technical problem that when welding double-bend pipes on oil / gas pipelines, the airbag is easily stuck at the bend near the pipeline outlet, making it difficult to remove the airbag from the pipeline and thus reducing operational risks; this invention eliminates the need to open an airbag removal hole in the middle of the double-bend pipe, reducing damage to the pipeline structure and maintaining the structural strength of the pipeline itself; the construction method of this invention is simple and effective, enabling the airbag to be easily removed from the double-bend pipe without damage, reducing the difficulty of removing the airbag from the double-bend pipe, making it easy to remove the airbag temporarily blocking the pipeline on oil / gas pipelines without damaging the pipeline structure, ensuring the integrity of the pipeline structure, greatly improving construction efficiency, reducing economic costs, labor costs, and operational risks, and has broad application prospects. Attached Figure Description

[0022] To make the objectives, technical solutions, and advantages of the invention clearer, the invention will now be described in further detail with reference to the accompanying drawings, wherein:

[0023] Figure 1 This is a schematic diagram illustrating the application scenario of the oil / gas pipeline modification construction method of the present invention.

[0024] Figure 2 This is a schematic diagram of the airbag in its uninflated state and inflated state in the prior art of the present invention.

[0025] Figure 3 This is a schematic diagram illustrating the state of the airbag during bending when it is removed, as per the prior art of this invention.

[0026] Figure 4 This is a front view of one embodiment of the drag-reducing bracket of the present invention.

[0027] Figure 5 This is a top view of one embodiment of the drag-reducing bracket of the present invention.

[0028] Figure 6 This is a schematic diagram illustrating the working principle of one embodiment of the drag-reducing bracket of the present invention.

[0029] Figure 7 This is a front view of Embodiment 2 of the drag-reducing bracket of the present invention.

[0030] Figure 8 This is a top view of Embodiment 2 of the drag-reducing bracket of the present invention.

[0031] Figure 9 This is a schematic diagram illustrating the working principle of Embodiment 2 of the drag-reducing bracket of the present invention.

[0032] Figure 10 This is a front view of Embodiment 3 of the drag-reducing bracket of the present invention.

[0033] Figure 11 This is a top view of a third embodiment of the drag-reducing bracket of the present invention.

[0034] Figure 12 This is a schematic diagram illustrating the working principle of Embodiment 3 of the drag-reducing bracket of the present invention.

[0035] Figure 13 This is a perspective view of embodiment four of the drag-reducing bracket of the present invention.

[0036] Figure 14 This is a schematic diagram illustrating the working principle of Embodiment 4 of the drag-reducing bracket of the present invention.

[0037] Explanation of reference numerals in the attached drawings: 100, Oil / gas pipeline; 101, Double-bend pipeline; 102, Oil / gas; 103, Weld; 104, First bend section; 105, Second bend section; 200, Airbag; 201, Traction ring; 202, Inflation / Depression port; 203, Grease isolation wall; 204, Traction rope; 205, Air pipe; 206, End cap; 207, Cylinder; 300, Drag-reducing bracket; 301, Drag-reducing ball; 302, First extension rod; 303, Crossbar; 304, Second extension rod; 305, Roller; 306, Roller shaft; 307, Third extension rod; 308, Fourth extension rod; 309, Groove plate; 310, End. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0039] It should be noted that similar reference numerals and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the figures, or the orientation or positional relationship commonly used when the product is in use. They are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance. In addition, the terms "horizontal," "vertical," etc., do not indicate that the component is required to be absolutely horizontal or suspended, but can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted. In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0040] This invention can be applied to the modification of oil / gas pipelines, such as rerouting oil / gas pipelines, adding branches, and pipeline cutting and connection work during accident rescue. It solves the technical problem that when double-bend pipes need to be welded on oil / gas pipelines, the pressure-bearing airbag is easily stuck at the bend of the double-bend pipe, making it difficult to remove the airbag from the oil / gas pipeline.

[0041] Based on the above-mentioned technical problems, this invention discloses a method for modifying an oil / gas pipeline. One end of the oil / gas pipeline 100 has an interface for welding a double-bend pipe 101. The double-bend pipe 101 includes a first pipe section, a second pipe section, and a third pipe section. The first pipe section is used for welding to the interface. The second pipe section is perpendicular to the pipe extension directions of the first and third pipe sections, respectively, and the pipe extension directions of the first and third pipe sections are parallel. The first and second pipe sections are connected by a first bend 104, which is close to the interface. The second and third pipe sections are connected by a second bend 105. 4. The forward and reverse bending directions of the second bending section 105 are opposite. First, an airbag 200 with positive air pressure bearing capacity is used to temporarily isolate and seal the oil and gas 102 at the interface of the oil and gas pipeline. Then, the first pipe section is welded at the interface. After the first pipe section is welded to the interface, a drag-reducing support 300 is inserted from the third pipe section and movably placed inside the second bending section 105. The drag-reducing support 300 can cause the airbag 200 to deform inward and reduce the frictional resistance when the airbag 200 is dragged in the pipeline. Then, the drag-reducing support 300 is removed and the airbag 200 is pulled out from the pipe opening of the third pipe section, thus completing the modification construction of the oil and gas pipeline 100.

[0042] Specifically, the airbag 200 is made of oil-resistant hard rubber and has a certain internal pressure bearing capacity. The airbag 200 includes a cylindrical body 207 and an end cap 206. The cylindrical body 207 is cylindrical, and the end cap 206 is a hemispherical end cap or an elliptical end cap. The end cap 206 and the cylindrical body 207 are fixedly connected by heat fusion or bonding, or the end cap and the cylindrical body are integrally formed. The outer surface of one of the end caps 206 of the airbag 200 has a vent and a traction ring 201. The vent is equipped with a lead-out inflation / deflation valve, which is used to connect to the vent pipe 205. The traction ring 201 has a traction hole, which is used to fix the traction rope 204.

[0043] Specifically, the pressure of the airbag 200 after inflation is controlled at 0.05~0.10 MPa, and the gas filled in the airbag 200 is an inert gas, preferably nitrogen.

[0044] Specifically, after welding one end of the double-bend pipe 101 to the oil / gas pipeline interface, the pressurized gas in the airbag 200 is first released. Then, the airbag 200 is pulled out of the pipe using the traction rope 204. When pulled to the second bend section 105, the drag-reducing bracket 300 is inserted into the second bend section 105, so that the drag-reducing bracket 300 abuts against the airbag 200. The drag-reducing bracket 300 applies pressure to the airbag 200, causing the airbag 200 to undergo inward deformation at this second bend section 105. This causes the airbag 200 to move in the bending direction of the second bend section 105, changing the direction of movement of the airbag 200, and making it easier to pull out the airbag 200. At the same time as the airbag 200 is pulled out, the drag-reducing bracket 300 is pulled out of the pipe along with the airbag 200.

[0045] Specifically, the drag-reducing bracket 300 is made of metal, preferably carbon steel or stainless steel.

[0046] The drag-reducing support 300, which can cause the airbag 200 to deform inward, has the following structural forms:

[0047] In one embodiment of the drag-reducing bracket 300 structure, the drag-reducing end is a drag-reducing ball 301, and the drag-reducing ball 301 is fixedly connected to one end of the first extension rod 302; as shown... Figures 4 to 6 As shown, the first extension rod 302 extends beyond the double-bend pipe 101 at the end away from the drag-reducing ball. The drag-reducing ball 301 abuts against the airbag wall. When the first extension rod 302 is pushed by an external force, it can transmit force to the drag-reducing ball 301, thereby causing the airbag 200 to undergo inward deformation. Then, the traction rope 204 is pulled to pull the airbag 200 and the drag-reducing bracket 300 out of the pipe at the same time.

[0048] In a second embodiment of the drag-reducing bracket 300 structure, the drag-reducing end is a crossbar 303, and one end of the crossbar 303 is fixedly connected to a second extension rod 304; for example... Figures 7 to 9 As shown, the end of the second extension rod 304 away from the crossbar extends outside the double-bend pipe 101. The crossbar 303 abuts against the airbag wall. When the second extension rod 304 is pushed by an external force, it can transmit force to the crossbar 303, thereby causing the airbag 200 to undergo inward deformation. Then, the traction rope 204 is pulled to pull the airbag 200 and the drag-reducing bracket 300 out of the pipe.

[0049] Compared to the drag-reducing ball 301, the crossbar 303 has a larger contact area with the airbag wall, which makes the contact area between the airbag wall and the bend of the second bend section smaller, resulting in less frictional resistance when the airbag moves in the double-bend pipe, and further reducing the resistance when the airbag 200 is pulled out.

[0050] In a third embodiment of the drag-reducing bracket 300 structure, the drag-reducing end is a roller 305, and rollers 306 are fixedly connected to both ends of the roller 305. Each roller 306 is rotatably connected to a third extension rod 307; for example... Figures 10 to 12 As shown, the end of the third extension rod 307 away from the roller extends beyond the double-bend pipe 101. The roller 305 abuts against the airbag wall. When the third extension rod 307 is pushed by an external force, it can transmit force to the roller 305, thereby causing the airbag 200 to undergo inward deformation. Then, the traction rope 204 and the third extension rod 307 are pulled at the same time to pull the airbag 200 and the drag-reducing bracket 300 out of the pipe simultaneously.

[0051] Compared to the crossbar 303, the roller 305 not only increases the contact area with the airbag wall and reduces the contact area between the airbag wall and the bend, but also plays a role in conveying the airbag 200. When the airbag wall contacts the roller 305, it can roll on the roller 305, further reducing the frictional resistance when pulling the airbag 200. At the same time, it can also change the direction of the pulling force on the airbag, making the airbag 200 easier to pull out.

[0052] In a fourth embodiment of the drag-reducing bracket 300 structure, the drag-reducing end is a grooved plate 309. One end of a fourth extension rod 308 is fixedly connected to one side of the grooved plate 309. The grooved plate 309 has an arc-shaped groove, and the center line of its bottom is perpendicular to the extension direction of the fourth extension rod 308. On the side of the grooved plate 309 away from the fourth extension rod 308, there is a protruding, laterally extending end 310. The end 310 is cylindrical, and its extension direction is parallel to the center line of the bottom of the grooved plate 309. Figure 13 and Figure 14 As shown, the end of the fourth extension rod 308 away from the grooved plate extends beyond the double-bend pipe 101. The end 310 first abuts against the airbag wall. When the fourth extension rod 308 is pushed by an external force, it can transmit force to the end 310, thereby causing the airbag 200 to undergo concave deformation. Then, the airbag wall at the remaining position on the concave deformation side is in a convex shape relative to the concave part. The convex part enters the grooved plate 309, and the grooved plate 309 has a locking effect on the concave deformed airbag 200. Then, the traction rope 204 is pulled. At this time, the components that simultaneously generate pulling force on the airbag 200 are the traction rope 204 and the grooved plate 309. The combination of the two can pull the airbag 200 out of the pipe.

[0053] Compared with the above-mentioned embodiments of the drag-reducing bracket 300 structure, the airbag wall with the groove plate 309 has the advantages of being able to apply force to the airbag 200 to deform it, and at the same time, it can assist the traction rope 204 in applying force to pull the airbag 200, which can further reduce the difficulty of the airbag 200 being pulled out from the second bending section 105.

[0054] Preferably, grease is pre-applied to the end 310 so that when the end 310 applies force to the airbag 200 to deform it inward, the friction between the end 310 and the airbag 200 is reduced, thereby enhancing the pulling effect of the groove plate 309.

[0055] Preferably, a camera is also installed on the extension rod, which can observe the situation inside the pipe in real time and flexibly adjust the position of the resistance-reducing bracket 300.

[0056] Preferably, before the airbag 200 is installed in the oil-gas pipeline 100, grease is applied to the outer periphery of the uninflated airbag 200 to enhance the sealing between the airbag 200 and the pipeline wall, and to reduce the frictional resistance between the airbag 200 and the pipeline wall when the airbag 200 is pulled inside the pipeline. Then, the airbag 200 is inflated. When the airbag 200 is inflated to a certain pressure, the outlet inflation / deflation valve is closed, and grease is filled at the air vent of the airbag 200 to form a grease isolation wall 203, preventing the oil and gas 102 in the oil-gas pipeline 100 from flowing to the pipeline welding area. The thickness of the grease isolation cavity is 5-10 cm.

[0057] Preferably, grease is applied to the drag-reducing end of the extension rod to reduce the frictional resistance of the airbag 200 as it passes through the second bend 105.

[0058] Preferably, lubricating oil is applied to the inner walls of the first bend section 104 and the second bend section 105 of the double-bend pipe 101 to reduce the frictional resistance when the airbag 200 moves along the pipe.

[0059] The inventive principles of this invention will now be explained in detail.

[0060] like Figure 1 As shown, Figure 1The diagram illustrates an application scenario of the oil / gas pipeline modification construction method disclosed in this invention. The oil / gas pipeline 100 is originally filled with oil and gas 102. An uninflated airbag 200 is placed 20-30 cm away from the pipeline interface. An inflation device is connected through an inflation pipe 205, and gas is injected into the airbag 200 using the inflation device, causing the airbag 200 to inflate and adhere tightly to the inner wall of the pipeline, forming an isolation seal. Then, a grease isolation wall 203 of about 5-10 cm is built on the side of the airbag 200 facing the pipeline interface to enhance the sealing effect of the airbag 200 on the oil / gas pipeline 100.

[0061] Specifically, the grease isolation wall 203 is closely attached to the airbag 200. When constructing the grease isolation wall 203, first clean the inner wall of the pipe section to ensure that the inner wall of the pipe section between the airbag 200 and the oil / gas pipeline interface is clean and free of mechanical impurities. Then, mix the grease and dry powder evenly in a ratio of 1:2.6 to 1:3.0 to form a block-shaped grease blank. Finally, build the grease blank on one side of the airbag 200. The thickness of the completed grease isolation wall 203 is greater than or equal to the pipe diameter, and the minimum thickness is not less than 100 mm. After the construction of the grease isolation wall 203 is completed, use a combustible gas detector to test the concentration of 102 at the grease isolation wall 203. If the on-site test result is lower than 15% of the lower explosive limit of 102, the subsequent work can continue. If it is higher than 15% of the lower explosive limit of 102, the cause needs to be found, and the on-site test result needs to be adjusted to be lower than 15% of the lower explosive limit of 102 before the subsequent work can continue.

[0062] like Figure 2 As shown, the rubber airbag 200 is characterized by its certain pressure resistance and chemical corrosion resistance, and can withstand a certain pressure. Moreover, due to the hardness of the rubber material itself, it can maintain a certain hollow bladder structure when it is not inflated. When the airbag 200 is inflated, only a small amount of gas is needed to achieve a high pressure inside the airbag 200, so that the airbag 200 can expand relatively quickly and quickly seal the pipeline.

[0063] However, precisely because the rubber airbag 200 can maintain a certain hollow bladder structure even when uninflated, when connected to the double-bend pipe 101 at the oil / gas pipeline interface, the two bends in the pipe will create resistance to the pull-out process of the rubber airbag 200. Due to the constraint of the inner wall of the pipe bends, the rubber airbag 200 will deform. The force exerted on the airbag 200 by the first bend 104 makes the deformed shape of the airbag 200 even more unfavorable for reaching the second bend 105, especially the end cap 206 of the airbag 200 and the cylinder... Because the connection point of body 207 is relatively hard and not easily deformed, it is very easy to be blocked by the first bending section 104, making it difficult for airbag 200 to reach the second bending section 105. If the traction rope 204 is pulled too hard, it is easy to break the traction rope 204 or cause the traction ring 201 to fall off the airbag 200, thus causing the airbag 200 to be stuck in the pipeline, creating an operational risk. If the airbag 200 is to be removed at this time, the pipeline needs to be cut, which will result in a waste of human and material resources and increase time and material costs.

[0064] Figure 3 The image shows the changes in shape of the uninflated airbag 200 as it passes through two bends in sequence after being removed from the double-bend pipe 101. Figure 3 In the figure, F represents the tension of the traction rope 204 on the airbag 200. As shown in the figure, shape A represents the change shape of the airbag 200 when it passes through the first bend section 104. When the airbag 200 passes through the first bend section 104, the airbag 200 enters the first bend section 104 with the cylinder 207 parallel to the first tube. When the airbag 200 continues to be subjected to an upward oblique tension, the end cap 206 of the airbag 200 abuts against the small curvature tube wall of the first bend section 104 and can rotate around the abutment point as the origin, so that the end cap 206 can pass through the first bend section 104 smoothly. Then, as the traction rope 204 continues to pull, the cylinder 207 of the airbag 200 abuts against the small curvature tube wall of the first bend section 104 and then deforms. After the cylinder 207 passes through the first bend section 104, the other end cap 206 of the airbag 200 also follows through the first bend section 104.

[0065] After the airbag 200 enters the second section, because the tension of the traction rope 204 on the airbag 200 is still inclined, under the continuous action of the inclined tension, the shape of the airbag 200 changes. Figure 3 In the B-shape, the upper end cap 206 undergoes inward deformation due to the inclined tension. The inward deformation reduces the space at the connection between the cylinder 207 and the end cap 206 that can deform. At the same time, the entire airbag 200 tilts and rises in the direction of the tension.

[0066] Next, the airbag 200 enters the second bend section 105. The inflation / deflation port 202 installed on the end cap 206 of the airbag 200 abuts against the top tube wall. The joint between the end cap 206 and the cylinder 207 abuts against the slightly curved tube wall of the second bend section 105. The traction rope 204 continues to be pulled. Due to the concave deformation of the end cap 206, the joint between the end cap 206 and the cylinder 207 is squeezed, making it difficult for the joint to deform further. This causes the entire airbag 200 to rotate, and its shape changes. Figure 3 The airbag 200 is in the C-shape. Therefore, the airbag 200 can easily get stuck in the second bend section 105, especially at the joint between the end cap 206 and the cylinder 207 on the airbag 200, which makes it difficult to pull the entire airbag 200 out of the pipe.

[0067] At this point, a movable drag-reducing bracket 300 is placed in the second bend section 105 to help the part where the airbag 200 is locked to undergo inward deformation, causing the center line of the airbag 200 to rotate toward the bending direction of the second bend section 105, thereby changing the direction of movement of the airbag 200 and allowing the airbag 200 to pass smoothly through the second bend section 105; finally, the drag-reducing bracket 300 and the airbag 200 are pulled at the same time, so that they are taken out from the double-bend pipe 101 near the second bend section 105, completing the oil / gas pipeline modification construction.

[0068] Analyzing the force conditions of the airbags 200 in various forms, when the direction of the pulling force on the airbag 200 is parallel to the center line of the airbag 200, the airbag 200 is easily pulled out. If the direction of the pulling force is tilted, the airbag 200 is prone to local deformation, making it difficult to pull out at the bend of the pipe. At the same time, the pulling force that the airbag 200 can withstand is affected by the structural strength of the traction ring 201 and the traction rope 204. The pulling force cannot be increased indefinitely, otherwise the traction rope 204 may break, causing the airbag 200 to remain stuck in the pipe, which will affect the construction.

[0069] The construction method for modifying oil / gas pipelines disclosed in this invention has the following technical advantages: This invention can be applied to the modification of oil / gas pipelines, such as rerouting, adding branches, and cutting off and connecting pipelines during emergency rescue operations; it solves the technical problem that when welding double-bend pipes to oil / gas pipelines, the airbag easily gets stuck at the bend near the pipeline outlet, making it difficult to remove the airbag; this invention eliminates the need for additional airbag removal holes in the middle section of the double-bend pipe, reducing damage to the pipeline structure and maintaining the structural strength of the pipeline itself; the construction method of this invention is simple and effective, enabling easy and undamaged removal of the airbag from the double-bend pipe, reducing the difficulty of removing the airbag, and allowing for easy removal of the airbag temporarily used to block the pipeline on oil / gas pipelines without damaging the pipeline structure, ensuring the integrity of the pipeline structure, greatly improving construction efficiency, and reducing economic, labor, and time costs, thus having broad application prospects.

[0070] It is understood that the present invention has been described through some embodiments, and those skilled in the art will recognize that various changes or equivalent substitutions can be made to these features and embodiments without departing from the spirit and scope of the invention. Under the teachings of the present invention, modifications can be made to these features and embodiments to adapt to specific situations and materials without departing from the spirit and scope of the invention. The embodiments described in this invention are only a part of the embodiments of the invention, not all of them. The components of the embodiments of the invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. Therefore, the invention is not limited to the specific embodiments disclosed herein, and all other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the present invention.

Claims

1. A method for modifying an oil / gas pipeline, wherein one end of the oil / gas pipeline has an interface for welding a double-bend pipe, the double-bend pipe comprising a first pipe section, a second pipe section, and a third pipe section; the first pipe section is used for welding to the interface; the second pipe section is perpendicular to the pipe extension directions of the first and third pipe sections respectively; the pipe extension directions of the first and third pipe sections are parallel; the first and second pipe sections are connected by a first bend section near the interface; the second and third pipe sections are connected by a second bend section; the clockwise and counterclockwise bending directions of the first and second bend sections are opposite. characterized in that First, an airbag with positive pressure bearing capacity is used to temporarily isolate and seal the oil and gas in the oil / gas pipeline at the interface; then, the first pipe section is welded at the interface. After the first pipe section is welded to the interface, the drag-reducing support is inserted into the third pipe section and movably placed in the second bend section. The drag-reducing support can cause the airbag to deform inward and reduce the frictional resistance when the airbag is dragged in the pipeline. Then, the drag-reducing support is removed and the airbag is pulled to remove the airbag from the pipe opening of the third pipe section, thus completing the modification construction of the oil and gas pipeline. The drag-reducing support includes an extension rod and a drag-reducing end fixedly connected to one end of the extension rod. The other end of the extension rod is located outside the third pipe section. The extension rod can be pushed by an external force and drive the drag-reducing end to apply force to the airbag, causing the airbag to deform inward, reducing the air pressure inside the airbag and reducing the volume of the airbag. When the airbag deforms inward, the airbag can move along the third pipe section to the outside of the pipe under the pulling action of the external force. The drag-reducing end is a grooved plate, with one end of a fourth extension rod fixedly connected to one side of the grooved plate. The grooved plate has an arcuate groove, and the center line of the bottom of the grooved plate is perpendicular to the extension direction of the fourth extension rod. On the side of the grooved plate away from the fourth extension rod, there is a protruding and laterally extending end, which is cylindrical and extends parallel to the center line of the bottom of the grooved plate. The end of the fourth extension rod away from the grooved plate extends beyond the double-bend pipe. The end first abuts against the airbag wall. When the fourth extension rod is pushed by an external force, it can transmit force to the end, causing the airbag to undergo inward deformation. The airbag wall at the remaining position on the inwardly deformed side is convex relative to the inwardly deformed part, and the convex part enters the grooved plate. The grooved plate then acts as a stop for the inwardly deformed airbag. Then, the traction rope and the fourth extension rod are pulled simultaneously. At this time, the components that simultaneously exert pulling force on the airbag are the traction rope and the grooved plate. The combination of the two can pull the airbag and the drag-reducing bracket out of the pipe at the same time.

2. The oil and gas containing oil / gas pipeline retrofit construction method according to claim 1, characterized by, Before the airbag is installed in the oil-gas pipeline, grease is applied to the outer periphery of the uninflated airbag to enhance the airtightness between the airbag surface and the pipeline wall, and at the same time reduce the frictional resistance between the airbag and the pipeline wall when the airbag is pulled in the pipeline. Then the airbag is inflated. When the airbag is inflated to a certain pressure, the outlet inflation / deflation valve is closed, and grease is filled at the air vent of the airbag to form a grease isolation wall to prevent the oil and gas in the oil-gas pipeline from flowing to the pipeline welding area.

3. The oil and gas containing pipeline retrofit construction method of claim 1, wherein, Apply grease to the drag-reducing end of the extension rod to reduce frictional resistance when the airbag passes through the second bend.

4. The method of revamping an oil / gas pipeline according to any one of claims 1 to 3, characterized in that, Lubricating oil is applied to the inner walls of the first and second bends of the double-bend pipe to reduce the frictional resistance as the airbag moves along the pipe.

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