Freezing net plugging device for dealing with blowout and construction method of freezing net plugging device

Abstract

The invention discloses a freezing net plugging device for dealing with blowout and a construction method thereof, and relates to the technical field of combustible ice mining, a net cover unit comprises a main pipeline, branch pipelines staggered with the path of the pipe wall of the main pipeline, and fins arranged on the outer walls of the main pipeline and the branch pipelines; the main pipeline is spirally coiled in the vertical direction, and the opening diameter of the main pipeline is gradually reduced from the bottom to the top. The freezing net plugging device meets the requirement for all-directional sealing of the position of a well nozzle, and it is guaranteed that good sealing performance can be kept even under the high-pressure and low-temperature conditions; and in the sealing process, a natural gas hydrate flowing channel is gradually reduced, and it is guaranteed that the sealing process can be conducted stably.

Description

Technical Field

[0001] The present invention relates to the field of combustible ice exploitation, and particularly to a freezing net plugging device for dealing with blowout and its construction method. Background Art

[0002] Natural gas hydrate, commonly known as "combustible ice", is an ice-like crystalline substance formed by natural gas and water under high pressure and low temperature conditions; such substances are mainly distributed in deep-sea sediments or permafrost on land, and are regarded as important potential clean energy sources in the 21st century due to their huge reserves, low pollution and high calorific value.

[0003] The distribution of natural gas hydrates in the deep sea has strict requirements for environmental conditions, and specific low temperature and high pressure conditions need to be met to maintain its stability; currently, the main methods for exploiting natural gas hydrates include thermal stimulation exploitation method, pressure reduction exploitation method, and CO2 replacement exploitation method, etc.; the core principle of these methods is to decompose natural gas hydrates by changing temperature or pressure, so as to achieve effective exploitation of natural gas.

[0004] However, in the actual exploitation process, due to the complex and changeable seabed geological conditions, once the operation is improper and the pressure or temperature changes greatly, it may cause the rapid decomposition of natural gas hydrates, and even a chain reaction, resulting in blowout; when dealing with blowout, traditional capping measures are difficult to be effectively implemented in the deep-sea environment, because they usually rely on the reaction force provided by the formation to suppress gas eruption, and in soft formation conditions, this reaction force is often insufficient to ensure the plugging effect; in addition, traditional plugging methods are difficult to achieve full-round sealing, especially when facing complex seabed topography, they are even more powerless. Summary of the Invention

[0005] Object of the Invention: The technical problem to be solved by the present invention is how to solve the problems that the existing seabed combustible ice exploitation technology is difficult to effectively deal with blowout, and the traditional plugging methods have poor effects under complex geological conditions.

[0006] Technical Solution: The present invention provides a freezing net plugging device for dealing with blowout, which includes a net cover unit. The net cover unit includes a main pipeline, a branch pipeline intersecting with the path of the main pipeline wall, and fins arranged on the outer walls of the main pipeline and the branch pipeline; the main pipeline spirally winds along the vertical direction, and its opening diameter gradually decreases from bottom to top.

[0007] Furthermore, a support unit is arranged at the bottom of the main pipeline of the device. The support unit includes a ground nail, a valve seat arranged inside the ground nail, a valve core arranged inside the valve seat, and a piston rod arranged inside the valve seat and connected to the valve core;

[0008] The ground nail is internally partitioned into a crown portion and a leg portion, and the valve seat is disposed inside the crown portion;

[0009] Barbs are provided on the outer wall of the leg portion. The leg portion is buried in the sea mud, and liquid nitrogen can be stored inside it.

[0010] Furthermore, the valve seat of the device includes a first cavity opened inside it. The first cavity includes an injection pipe communicating with its interior;

[0011] A first through hole is opened at the bottom of the crown portion. The first cavity communicates with the leg portion through the first through hole.

[0012] Furthermore, the valve seat of the device further includes a third cavity provided at its central position;

[0013] A second through hole is opened at the top of the leg portion. The leg portion communicates with the third cavity through the second through hole;

[0014] The first cavity further includes a first perforation communicating with the third cavity;

[0015] The valve core moves inside the third cavity;

[0016] The fluid passage opened inside the valve core can coincide with the position of the first perforation;

[0017] The valve core includes a reset member provided at its end;

[0018] The reset member can abut against the top wall of the third cavity.

[0019] Furthermore, the piston rod of the device is connected to the valve core. The inside of the piston rod is a hollow structure, and the piston rod communicates with the fluid passage;

[0020] The piston rod penetrates through the valve seat and extends to its outside;

[0021] A discharge pipe is connected to the top of the valve seat, and the discharge pipe communicates with the bottom of the main pipeline.

[0022] Furthermore, the mesh cover unit of the device includes a return pipeline provided at the top of the main pipeline;

[0023] The valve seat includes a second cavity provided inside it. The second cavity is spaced apart from the first cavity;

[0024] The second cavity includes a return pipe communicating with its interior;

[0025] The valve seat further includes a fourth cavity above the third cavity and a fifth cavity above the fourth cavity;

[0026] The second cavity communicates with the fourth cavity through a second perforation formed in its side wall, and the second cavity communicates with the fifth cavity through a third perforation formed in its side wall.

[0027] Furthermore, the piston rod of the device includes a pressing plate disposed on its outer wall, and the pressing plate moves inside the fourth cavity.

[0028] The movement of the piston rod can further change the size of the opening of the fluid passage.

[0029] Furthermore, a plug is sleeved on the outer wall of the piston rod of the device.

[0030] The plug moves inside the fifth cavity.

[0031] The fifth cavity includes a fourth perforation communicating with the discharge pipe and a pressure relief pipeline communicating with the outside atmosphere.

[0032] Furthermore, the closing unit of the device, the closing unit includes a docking pipe and a closing valve for opening and closing the docking pipe.

[0033] Liquid nitrogen is introduced into the net cover unit, and it forms a protective cover by freezing seawater at the blowout position.

[0034] Advantageous effects: Compared with the prior art, the remarkable advantages of the present invention are as follows: The freeze net plugging device can meet the all-round closing requirement of the blowout port position, ensuring good sealing performance even under high-pressure and low-temperature conditions; during the closing process, the channel for the flow of natural gas hydrate is gradually reduced, ensuring a smooth plugging process; at the same time, ground nails are inserted into the sea mud to form a frozen layer, forming a stable reaction force to ensure the stability of the plugging structure.

[0035] Therefore, the object of the invention: The technical problem to be solved by the present invention is the problem that the existing deep-sea blowout plugging device is inconvenient in actual deployment and operation.

[0036] Technical solution: The present invention provides a construction method for a freeze net plugging device for dealing with blowouts, which includes S1: Insert ground nails into the sea mud around the blowout port, and then connect the net cover unit to the ground nails to open the internal channel of the docking pipe.

[0037] S2: Introduce liquid nitrogen. The liquid nitrogen first enters the leg position of the ground nail, then enters the inside of the main pipeline along the bottom of the main pipeline, and moves upward along the internal channels of the main pipeline and the branch pipes.

[0038] First, the ground nails freeze the sea mud, which can provide sufficient reaction force for fixing the device; the net cover freezes the seawater upward from the bottom to form a protective cover. During this process, the channel for gas flow gradually decreases, but it is ensured that there is always a channel for gas flow.

[0039] S3: The liquid nitrogen and nitrogen that enter the top of the wire mesh unit flow back into the valve seat through the reflux pipeline. Part of them is discharged into the atmosphere through the pressure relief pipeline, and part of them flows back into the wire mesh through the fourth perforation. The wire mesh unit forms a protective cover, and then the docking pipe channel is closed by the closing valve to complete the plugging of the blowout.

[0040] Beneficial effects: Compared with the prior art, the remarkable advantages of the present invention are as follows: A firm and stable protective cover can be formed at the blowout location through the above construction method; The ground nails penetrate deep into the sea mud to form a frozen layer, providing sufficient reaction force for the fixation of the device to resist the impact brought by the blowout; At the same time, the entire protective cover is gradually formed during the forming process, ensuring that there is a channel for natural gas to flow during the forming process of the protective cover and ensuring that the plugging process can proceed smoothly. Description of the Drawings

[0041] Figure 1 Shows the structural schematic diagram of the freezing net sealing device;

[0042] Figure 2 Shows the structural schematic diagram of the support unit;

[0043] Figure 3 Shows the connection schematic diagram of the first cavity and the leg;

[0044] Figure 4 Shows the connection schematic diagram of the first cavity and the piston rod;

[0045] Figure 5 Shows the connection schematic diagram of the second cavity and the fifth cavity;

[0046] Figure 6 Shows the connection schematic diagram of the pressure relief pipeline and the fifth cavity;

[0047] Figure 7 Shows the structural schematic diagram of the freezing wire mesh cover forming.

[0048] In the figure: 1. Mesh cover unit; 11. Main pipeline; 12. Branch pipeline; 13. Fins; 14. Countercurrent pipeline; 2. Support unit; 21. Ground nail; 211. Crown; 2111. First through hole; 212. Leg; 2121. Second through hole; 22. Valve seat; 221. First cavity; 2211. Injection pipe; 2212. First perforation; 222. Second cavity; 2221. Return pipe; 2222. Second perforation; 2223. Third perforation; 223. Third cavity; 224. Fourth cavity; 225. Fifth cavity; 2251. Fourth perforation; 2252. Pressure relief pipeline; 23. Spool; 231. Fluid passage; 232. Reset member; 24. Piston rod; 241. Pressure plate; 25. Plug; 26. Discharge pipe; 27. Barbs; 3. Closing unit; 31. Docking pipe; 32. Closing valve. Detailed implementation mode

[0049] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings.

[0050] The terms used in the present invention are those general terms currently widely used in the art in consideration of the functions of the present invention, but these terms may change according to the intentions of those of ordinary skill in the art, precedents, or new technologies in the art. In addition, specific terms may be selected by the applicant, and in this case, their detailed meanings will be described in the detailed description of the present invention. Therefore, the terms used in the specification should not be understood as simple names, but based on the meanings of the terms and the overall description of the present invention.

[0051] Referring to Figure 1 , this embodiment provides a freezing net plugging device for coping with blowouts, including a mesh cover unit 1. The mesh cover unit 1 includes a main pipeline 11, a branch pipeline 12 that intersects with the path of the main pipeline 11 pipe wall, and fins 13 provided on the outer walls of the main pipeline 11 and the branch pipeline 12; the main pipeline 11 is spirally wound along the vertical direction, and its opening diameter gradually decreases from bottom to top.

[0052] In this embodiment, the main pipeline 11 is distributed along the vertical direction in a spiral winding manner, the diameter of the bottom opening of the main pipeline 11 is larger than the diameter of the top opening; and there is a certain distance between adjacent pipes during the winding of the main pipeline 11; and the inside of the main pipeline 11 is interconnected; the diameter of the branch pipeline 12 is smaller than the diameter of the pipeline of the main pipeline 11; the branch pipeline 12 penetrates through the main pipeline 11 along the spiral direction.

[0053] The branch pipeline 12 serves to connect multiple groups of main pipelines 11, and the main pipelines 11 are connected by bolts during the installation process; during use, multiple scattered main pipelines 11 need to be combined and spliced.

[0054] Furthermore, multiple groups of fins are provided on the outer walls of the main pipeline 11 and the branch pipelines 12, and the fins can play a role in heat conduction, conducting the low temperature released by the vaporization of liquid nitrogen to the seawater around the pipeline network. At the same time, the fins can further block the flow rate of seawater, further ensuring the formation of the frozen shield.

[0055] It should be noted that liquid nitrogen enters the inside of the main pipeline 11 from the bottom, and then gradually flows from the bottom of the main pipeline 11 towards the top of the mesh cover. During the flow process, it can enter the space between adjacent main pipelines 11 through the branch pipelines 12, thereby forming a process of gradually forming a frozen shield from the bottom to the top.

[0056] The branch pipelines 12 are located between adjacent main pipelines 11, which can further make up for the problem of too large a gap between the main pipelines 11, making the structure of the frozen shield more stable.

[0057] In summary, the mesh cover unit 1 provided can slowly form a shield at the blowout location, thereby overcoming the problem that the shield cannot block the blowout location due to the large impact force at the blowout location. And during the formation of the shield, the blowout location can be gradually blocked, reducing potential safety hazards to a certain extent.

[0058] Reference Figure 1 and Figure 3 As an alternative embodiment, a support unit 2 is provided at the bottom of the main pipeline 11. The support unit 2 includes a ground nail 21, a valve seat 22 arranged inside the ground nail 21, a valve core 23 arranged inside the valve seat 22, and a piston rod 24 connected to the valve core 23 and arranged inside the valve seat 22. The inside of the ground nail 21 is divided into a crown part 211 and a leg part 212, and the valve seat 22 is arranged inside the crown part 211. Barbs 27 are provided on the outer wall of the leg part 212, and the leg part 212 is buried in the sea mud, and liquid nitrogen can be stored inside it.

[0059] In this embodiment, in order to further ensure that the mesh cover is more firmly located on the seabed, a ground nail 21 is provided. The leg part 212 of the ground nail 21 is inserted into the sea mud, and when liquid nitrogen enters the leg part 212, the sea mud can be frozen, thereby forming a stable support structure on the seabed.

[0060] Furthermore, barbs 27 are welded and fixed on the outer wall of the leg part 212, and the angle between the barbs 27 and the leg part 212 is an acute angle, and the opening of this acute angle faces the top of the ground nail 21. The barbs 27 can make the leg part 212 more firmly fixed inside the sea mud, further improving the stability of the ground nail 21.

[0061] It should be noted that during the use of the device, liquid nitrogen will first enter the inside of the leg 212, firmly fix the leg 212 in the sea mud, and form a certain support by freezing the sea mud; then the liquid nitrogen that enters the inside of the leg 212 will enter the main pipeline 11, so as to further freeze the seawater on the outer wall of the mesh cover pipeline.

[0062] By inserting the ground nail 21 into the sea mud and using liquid nitrogen to freeze the sea mud, a firm fulcrum can be formed, which further improves the stability of the shield at the blowout location; the liquid nitrogen that enters the ground nail 21 will enter the inside of the main pipeline 11 from the bottom of the main pipeline 11; and continuously flow towards the top of the main pipeline 11, and gradually freeze the mesh cover into a sealed shield.

[0063] Reference Figure 3 , in an embodiment provided by the present application, the valve seat 22 includes a first cavity 221 opened inside it, and the first cavity 221 includes an injection pipe 2211 communicated with its inside; a first through hole 2111 is opened at the bottom of the crown portion 211, and the first cavity 221 is communicated with the leg 212 through the first through hole 2111.

[0064] In this embodiment, the valve seat 22 is arranged inside the crown portion 211, and the crown portion 211 is located on the upper surface of the sea mud; a first cavity 221 is arranged inside the valve seat 22, and the first cavity 221 is communicated with the injection pipe 2211. Liquid nitrogen enters the inside of the injection pipe 2211 through a pressurized pipeline, and pressure relief is realized at the connection between the injection pipe 2211 and the first cavity 221, and then the liquid nitrogen enters the inside of the first cavity 221.

[0065] Furthermore, the liquid nitrogen that enters the inside of the first cavity 221 will pass through the valve seat 22 along the first through hole 2111 and enter the inside of the leg 212, and gradually vaporize inside the leg 212; the liquid nitrogen absorbs heat during the vaporization process, so that the sea mud is frozen to form a stable ice cone.

[0066] In summary, the liquid nitrogen enters the inside of the leg 212 through the first cavity 221 and vaporizes inside the leg 212. The liquid nitrogen absorbs more heat during the vaporization process, so that the sea mud can be frozen and a firm ice cone is formed on the seabed, which can further provide stable support for the freezing device.

[0067] Reference Figure 4, in some embodiments, the valve seat 22 further includes a third cavity 223 disposed at its central position; a second through hole 2121 is formed at the top of the leg 212, and the leg 212 communicates with the third cavity 223 through the second through hole 2121; the first cavity 221 further includes a first through hole 2212 communicating with the third cavity 223; the valve element 23 moves inside the third cavity 223; a fluid passage 231 formed inside the valve element 23 can coincide with the position of the first through hole 2212; the valve element 23 includes a reset member 232 disposed at its end; the reset member 232 can abut against the top wall of the third cavity 223.

[0068] In this embodiment, during the vaporization of liquid nitrogen inside the leg 212, the pressure inside the leg 212 will increase. The high-pressure nitrogen can enter the inside of the third cavity 223 through the second through hole 2121 and can lift the valve element 23 located inside the third cavity; during the movement of the valve element 23, the reset member 232 is gradually compressed, thereby making the fluid passage 231 communicate with the first through hole 2212. Then, a part of the liquid nitrogen can be diverted, flow into the fluid passage 231 along the first through hole 2212, and then flow into the main pipeline 11.

[0069] It should be noted that a fluid passage 231 is provided at the top of the valve element 23. The elastic potential energy released by the fluid passage 231 in the normal state can press the valve element 23 against the bottom of the third cavity 223; make the side wall of the valve element 23 coincide with the position of the first through hole 2212, thereby ensuring that the liquid nitrogen entering the first cavity 221 can only enter the inner side of the leg 212 along the first through hole 2111.

[0070] During the continuous entry of liquid nitrogen into the leg 212, the liquid nitrogen inside the leg 212 continuously vaporizes, increasing the pressure inside the leg 212. The high-pressure nitrogen will enter the inside of the third cavity 223 through the second through hole 2121. When the pressure reaches a certain value, it can push the valve element 23 upward and squeeze the reset member 232.

[0071] It should be noted that during the upward movement of the valve element 23, the opening position of the fluid passage 231 gradually coincides with the position of the first through hole 2212, making the first through hole 2212 communicate with the fluid passage 231; at this time, the liquid nitrogen entering the first cavity 221 can be diverted; a part of the liquid nitrogen enters the inner side of the leg 212 through the first cavity 221, and another part enters the fluid passage 231 through the first cavity 221.

[0072] Preferably, when the valve core 23 leaves the bottom position of the third cavity 223, there is a perforation connecting the first cavity 221 and the bottom position of the third cavity 223; after the liquid nitrogen inside the inner side of the leg 212 enters the third cavity 223, it will flow back into the first cavity 221 along the perforation, so that the high-pressure liquid nitrogen and nitrogen mixture can enter the main pipeline 11 through the fluid channel 231.

[0073] In summary, when the leg 212 is filled with liquid nitrogen, the channel between the first perforation 2212 and the fluid channel 231 is opened; so that the liquid nitrogen can be shunted; thus realizing the operation of freezing the sea mud first and then freezing other devices, ensuring the stability of the formation of the shield.

[0074] Refer to Figure 3 , in an embodiment provided by the present application, it includes a piston rod 24 connected to the valve core 23. The inside of the piston rod 24 is a hollow structure, and the piston rod 24 is communicated with the fluid channel 231; the piston rod 24 penetrates through the valve seat 22 and extends to its outside; a discharge pipe 26 is connected to the top of the valve seat 22, and the discharge pipe 26 is communicated with the bottom of the main pipeline 11.

[0075] In this embodiment, the piston rod 24 and the valve core 23 can move synchronously. The fluid entering the fluid channel 231 can enter the piston rod 24; through the piston rod 24, the liquid nitrogen can enter the discharge pipe 26 and then enter the main pipeline 11.

[0076] It should be noted that the piston rod 24 and the valve core 23 are in interference fit. During the process of the valve core 23 being moved by an external force, the piston rod 24 can be driven to move synchronously.

[0077] Furthermore, the top of the piston rod 24 penetrates into the inner side of the discharge pipe 26, and the discharge pipe 26 is communicated with the main pipeline 11; the liquid nitrogen entering the discharge pipe 26 can enter the main pipeline 11.

[0078] Refer to Figure 1 、 Figure 6 and Figure 5 , in some embodiments, the mesh cover unit 1 includes a countercurrent pipeline 14 arranged on the top of the main pipeline 11; the valve seat 22 includes a second cavity 222 arranged inside it, and the second cavity 222 is spaced apart from the first cavity 221; the second cavity 222 includes a return pipe 2221 communicated with its inside; the valve seat 22 further includes a fourth cavity 224 above the third cavity 223 and a fifth cavity 225 above the fourth cavity 224; the second cavity 222 is communicated with the fourth cavity 224 through a second perforation 2222 opened on its side wall, and the second cavity 222 is communicated with the fifth cavity 225 through a third pipe hole 2223 opened on its side wall.

[0079] In this embodiment, after the liquid nitrogen fills the entire inside of the network pipe, the mixture of liquid nitrogen and nitrogen will enter the second cavity 222 along the countercurrent pipe 14 through the return pipe 2221; at this time, the entering mixture has a relatively high pressure; when entering the second cavity 222, it will pass through the second perforation 2222 and enter the fourth cavity 224, and downwardly squeeze the pressing plate 241 to move.

[0080] It should be noted that the second cavity 222 and the first cavity 221 are two relatively independent cavities, and the second cavity 222 is arranged at the middle position of the first cavity 221; after the high-pressure mixture enters the second cavity 222, it will pass through the second perforation 2222 and enter the fourth cavity 224; at this time, the pressure in the fourth cavity 224 is greater than the pressure in the third cavity 223, causing the pressing plate 241 to move downward.

[0081] During the downward movement of the piston rod 24, the plug 25 provided on its outer wall moves synchronously with it. When the plug 25 moves downward, the blocking of the position of the third perforation 2223 can be released; then the high-pressure liquid nitrogen located inside the second cavity 222 can enter the fifth cavity 225 through the third perforation 2223.

[0082] Furthermore, when the plug 25 moves downward, the pressure relief pipe 2252 and the fourth perforation 2251 inside the fifth cavity 225 are both in an open state, so that the high-pressure nitrogen can flow to the outside atmosphere along the pressure relief pipe 2252; and a part of the liquid nitrogen enters the inside of the network pipe through the fourth perforation 2251 for circulation.

[0083] Reference Figure 5 and Figure 6 , in an embodiment provided by the present application, the piston rod 24 includes a pressing plate 241 provided on its outer wall, and the pressing plate 241 moves inside the fourth cavity 224; the movement of the piston rod 24 can further change the opening size of the fluid passage 231.

[0084] In this embodiment, the pressing plate 241 moves inside the fourth cavity. The high-pressure mixture entering the second cavity 222 passes through the second perforation 2222 and enters the fourth cavity 224, and then the high-pressure mixture squeezes the pressing plate 241 to move the piston rod 24 downward.

[0085] During the downward movement of the piston rod 24, the position where the opening between the fluid passage 231 and the first perforation 2212 coincides gradually decreases, so that the amount of liquid nitrogen entering the discharge pipe 26 through the fluid passage 231 gradually decreases.

[0086] In summary, the amount of liquid nitrogen entering the inside of the network pipe through the piston rod 24 is reduced, so that more of the liquid nitrogen flowing back into the inside of the network pipe can be recycled, and the amount of liquid nitrogen used can be further reduced.

[0087] Reference Figure 5 and Figure 6 , in some embodiments, a plug 25 is sleeved on the outer wall of the piston rod 24; the plug 25 moves inside the fifth cavity 225; the fifth cavity 225 includes a fourth through hole 2251 communicating with the discharge pipe 26 and a pressure relief pipe 2252 communicating with the outside atmosphere.

[0088] In this embodiment, the plug 25 is in interference connection with the piston rod 24. As the plug 25 moves downward with the piston rod 24, three sets of channels are released during the downward movement of 25, so that the high-pressure mixture enters the inside of the fifth cavity 225.

[0089] Furthermore, the high-pressure nitrogen moves towards the outside atmosphere through the pressure relief pipe 2252, and a part of the liquid nitrogen enters the inside of the discharge pipe 26 through the fourth through hole 2251, and then can enter the inside of the network pipe to participate in the secondary cycle.

[0090] Reference Figures 5 to 7 , in an embodiment provided by the present application, it includes a closing unit 3. The closing unit 3 includes a docking pipe 31 and a closing valve 32 for opening and closing the docking pipe 31; liquid nitrogen is introduced into the network cover unit 1, and a protective cover is formed by freezing seawater at the blowout position.

[0091] In this embodiment, after the frozen network cover is formed, it will form a closed protective cover, so that the natural gas gushing out can only flow outward along the docking pipe 31. At this time, the diameter of the docking pipe 31 is small, and the protective cover can also be fully fixed outside the blowout point, making the operation of plugging the blowout point simpler.

[0092] Furthermore, during the complete plugging process, by starting the closing valve 32, the diameter of the flow channel inside the docking pipe 31 is gradually reduced, and finally the blowout point is completely plugged.

[0093] In summary, the frozen network plugging device meets the all-round closing requirements of the blowout port position, ensuring good sealing performance even under high-pressure and low-temperature conditions; gradually reducing the channel for the flow of natural gas hydrates during the closing process to ensure that the plugging process can proceed smoothly; at the same time, inserting ground nails into the sea mud to form a frozen layer to form a stable reaction force to ensure the stability of the plugging structure.

[0094] Refer to Figure 1, this embodiment provides a construction method for a freezing net plugging device for dealing with blowouts, including S1: Insert ground nails into the sea mud around the blowout opening, and then connect the net cover unit to the ground nails to open the internal passage of the docking pipe.

[0095] Check the state of the docking pipe 31 to ensure that its internal flow passage is open; if the shut-off valve 32 has been closed, it needs to be opened manually or through a remote control device.

[0096] Ensure that barbs 27 are welded to the outer wall of the leg 212 of the ground nail 21. The angle between these barbs and the leg is an acute angle, and the opening faces the top of the ground nail.

[0097] Slowly and steadily insert the leg 212 of the ground nail 21 into the sea mud around the blowout opening; use mechanical equipment or a submersible to assist in precise installation to ensure that the ground nail can penetrate to a sufficient depth to provide stable support.

[0098] After the ground nail 21 is installed, connect the bottom of the main pipeline 11 to the crown 211 of the ground nail 21; this step can be connected by a steel wire rope to connect the crown 211 and the main pipeline 11.

[0099] S2: Inject liquid nitrogen. The liquid nitrogen first enters the position of the leg of the ground nail, then enters the interior of the main pipeline along the bottom of the main pipeline, and moves upward along the internal passages of the main pipeline and the branch pipes;

[0100] First, freeze the sea mud through the ground nail to provide sufficient reaction force for fixing the device; the net cover continuously freezes seawater from the bottom up to form a protective cover. During this process, the channel for gas flow gradually decreases, but it is ensured that there is always a channel for gas flow.

[0101] Start injecting liquid nitrogen into the leg 212 of the ground nail 21 through the injection pipe 2211 of the valve seat 22; the liquid nitrogen will first fill the interior of the leg and quickly vaporize, absorbing a large amount of heat, thereby freezing the surrounding sea mud.

[0102] Monitor the pressure change in the leg 212 to ensure that as the liquid nitrogen is injected, the sea mud gradually freezes to form a solid support structure.

[0103] When the liquid nitrogen in the leg 212 starts to vaporize and freeze the sea mud, continue to inject liquid nitrogen so that it enters the first cavity 221 of the valve seat 22 through the first through hole 2111, and then enters the bottom of the main pipeline 11.

[0104] The liquid nitrogen flows from the bottom to the top in the main pipeline 11, and at the same time is further dispersed to the entire net cover unit 1 through the branch pipeline 12; the liquid nitrogen transfers the low temperature to the surrounding seawater through the fins 13, prompting the seawater to freeze and gradually form a frozen protective cover from the bottom to the top of the net cover.

[0105] S3: The liquid nitrogen and nitrogen that enter the top of the wire mesh unit flow back into the interior of the valve seat through the reflux pipe. Part of it is discharged into the atmosphere through the pressure relief pipe, and part of it flows back into the pipe network through the fourth perforation; the wire mesh unit forms a protective cover, and then the docking pipe channel is closed by the closing valve to complete the plugging of the blowout.

[0106] When the liquid nitrogen enters from the bottom of the main pipeline 11 and flows upward along the spiral path, it gradually vaporizes into nitrogen; when it reaches the top of the wire mesh unit 1, the mixture of liquid nitrogen and nitrogen will flow back through the countercurrent pipe 14 provided at the top of the main pipeline 11.

[0107] The countercurrent pipe 14 returns these mixtures to the second cavity 222 inside the valve seat 22.

[0108] Inside the second cavity 222, the mixture is divided into two parts: part of the high-pressure nitrogen is directly discharged into the atmosphere through the pressure relief pipe 2252; the other part flows back to the discharge pipe 26 through the fourth perforation 2251 and then re-enters the main pipeline 11 for recycling.

[0109] As the liquid nitrogen continues to be injected and transfers low temperature to the surrounding seawater through the fins 13, a complete frozen protective cover is gradually formed; this process requires continuous monitoring of temperature and pressure to ensure uniform cooling and no cracks or weak points occur.

[0110] After confirming that the frozen protective cover has completely covered the blowout area and the structure is strong enough, start to prepare to close the channel of the docking pipe 31.

[0111] Slowly start the closing valve 32 and gradually reduce the opening size of the docking pipe 31; this process should be carried out very carefully to avoid sudden pressure changes causing the protective cover to rupture or other dangerous situations.

[0112] Finally, when the docking pipe 31 is completely closed, the blowout port is completely sealed, and the effective plugging of the blowout is completed.

Claims

1. A freezing net plugging device for dealing with blowouts, characterized in that: include, A mesh cover unit (1), the mesh cover unit (1) comprising a main pipeline (11), a branch pipeline (12) intersecting with the pipeline wall path of the main pipeline (11), and fins (13) arranged on the outer walls of the main pipeline (11) and the branch pipeline (12); The main pipe (11) is spirally wound in the vertical direction, and its opening diameter gradually decreases from the bottom to the top.

2. The freezing net plugging device for dealing with blowout according to claim 1 is characterized in that: A support unit (2) is provided at the bottom of the main pipeline (11), and the support unit (2) comprises a ground nail (21), a valve seat (22) arranged inside the ground nail (21), a valve core (23) arranged inside the valve seat (22), and a piston rod (24) arranged inside the valve seat (22) and connected to the valve core (23); The interior of the ground nail (21) is divided into a crown portion (211) and a leg portion (212), and the valve seat (22) is arranged inside the crown portion (211); The outer wall of the leg (212) is provided with a barb (27); the leg (212) is buried in the sea mud, and liquid nitrogen can be stored inside the leg (212).

3. The freezing net plugging device for dealing with blowouts according to claim 2 is characterized in that: The valve seat (22) comprises a first cavity (221) opened therein, and the first cavity (221) comprises an injection pipe (2211) connected to the interior thereof; A first through hole (2111) is provided at the bottom of the crown portion (211), and the first cavity (221) is connected to the leg portion (212) through the first through hole (2111).

4. The freezing net plugging device for dealing with blowouts according to claim 3 is characterized in that: The valve seat (22) further comprises a third cavity (223) arranged at a central position thereof; A second through hole (2121) is provided on the top of the leg portion (212), and the leg portion (212) and the third cavity (223) are connected via the second through hole (2121); The first cavity (221) further comprises a first through hole (2212) communicating with the third cavity (223); The valve core (23) moves inside the third cavity (223); The fluid channel (231) opened inside the valve core (23) can coincide with the position of the first through hole (2212); The valve core (23) includes a reset member (232) arranged at an end thereof; The restoring member (232) can abut against the top wall of the third cavity (223).

5. The freezing net plugging device for dealing with blowouts according to claim 4 is characterized in that: The piston rod (24) is connected to the valve core (23), the interior of the piston rod (24) is a hollow structure, and the piston rod (24) is in communication with the fluid channel (231); The piston rod (24) passes through the valve seat (22) and extends to the outside thereof; The top of the valve seat (22) is connected to a discharge pipe (26), and the discharge pipe (26) is communicated with the bottom of the main pipeline (11).

6. The freezing net plugging device for dealing with blowouts according to claim 5 is characterized in that: The mesh cover unit (1) comprises a counter-flow pipe (14) arranged on the top of the main pipe (11); The valve seat (22) comprises a second cavity (222) arranged inside the valve seat, and the second cavity (222) is separated from the first cavity (221); The second cavity (222) includes a reflux pipe (2221) connected to the interior thereof; The valve seat (22) further comprises a fourth cavity (224) located above the third cavity (223), and a fifth cavity (225) located above the fourth cavity (224); The second cavity (222) is connected to the fourth cavity (224) via a second through hole (2222) provided in the side wall thereof, and the second cavity (222) is connected to the fifth cavity (225) via a third tube hole (2223) provided in the side wall thereof.

7. The freezing net plugging device for dealing with blowouts according to claim 6 is characterized in that: The piston rod (24) comprises a pressure plate (241) arranged on the outer wall thereof, and the pressure plate (241) is located inside the fourth cavity (224) and moves; The piston rod (24) moves and thereby changes the opening size of the fluid channel (231).

8. The freezing net plugging device for dealing with blowouts according to claim 6 is characterized in that: The outer wall of the piston rod (24) is sleeved with a plug (25); The plug (25) moves inside the fifth cavity (225); The fifth cavity (225) includes a fourth through hole (2251) connected to the discharge pipe (26), and a pressure relief pipe (2252) connected to the outside atmosphere.

9. The freezing net plugging device for dealing with blowouts according to any one of claims 1 to 4 or 7 to 8, characterized in that: Also includes A closing unit (3), the closing unit (3) comprising a butt joint pipe (31) and a closing valve (32) used for opening and closing the butt joint pipe (31); Liquid nitrogen is introduced into the mesh cover unit (1), which forms a protective cover by freezing seawater at the blowout location.

10. A construction method of a freezing net plugging device for dealing with blowouts, characterized in that: S1: insert the ground nails into the sea mud around the blowout port, then connect the mesh unit to the ground nails to open the internal channel of the butt-joint pipe; S2: Liquid nitrogen is introduced. The liquid nitrogen first enters the leg position of the ground nail, then enters the inside of the main pipe along the bottom of the main pipe, and moves upward along the internal channels of the main pipe and the branch pipe; First, the sea mud is frozen by ground nails to provide sufficient reaction force for the fixation of the device; the mesh cover continuously freezes the sea water from the bottom to form a protective cover. In this process, the channel for gas flow is gradually reduced, but it is guaranteed that there is always a channel for gas flow; S3: The liquid nitrogen and nitrogen gas entering the top of the mesh cover unit flow back to the inside of the valve seat through the reflux pipe, part of which is discharged to the atmosphere through the pressure relief pipe, and part of which flows back to the mesh pipe through the fourth perforation; The mesh cover unit forms a protective cover, and then the butt-joint pipe channel is closed by a closing valve to complete the plugging of the blowout.

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