A cavity medium replacement system and method applicable to subsea pipeline repair projects

Abstract

The present invention discloses a cavity medium replacement system and method applicable to subsea pipeline repair projects, which relates to the field of marine equipment. The system includes an air supply system, a valve panel, an equipment body, and a pumping system. The equipment body includes a floating cabin and an operation cabin. The air supply system is used to provide compressed air to the operation cabin and the floating cabin to replace the seawater in the cabins. The valve panel is used to control the on / off of each pipeline. The operation cabin of the equipment body is used to seal and surround the subsea pipeline to be repaired, and the seawater in the operation cabin and the floating cabin can be replaced with air, thereby providing a dry environment for subsequent repair operations. The pumping system is used to discharge the seawater in the operation cabin and the floating cabin out of the cabins, and cooperate with the air supply system to complete the replacement of seawater and air. Based on the above system and its cavity medium replacement method, the present invention replaces the water in the equipment with air, thereby providing a dry environment for subsequent subsea pipeline repair operations, greatly reducing the construction cost and construction difficulty, and shortening the operation time.

Description

Technical Field

[0001] The present invention relates to the field of marine equipment, and particularly to a cavity medium replacement system and method suitable for subsea pipeline repair projects. Background Art

[0002] With the further development of offshore oil resources, the ocean will become the main source of future oil production increase, and the corresponding technical requirements are also increasing. Subsea pipelines are an indispensable part of offshore oil and gas development. However, subsea pipelines are located on the seabed with a harsh environment. On the one hand, they are subjected to high internal temperature and pressure loads, and on the other hand, they are subjected to low external temperature loads, hydrostatic pressure, and long-term actions such as waves and ocean currents. Therefore, during the service process of subsea pipelines, it is inevitable to occur damage accumulation, deformation buckling, etc., which may lead to accidents. For this reason, it is necessary to regularly detect and repair subsea pipelines.

[0003] Common methods for subsea pipeline repair operations include fiber composite material methods, sleeve methods, welding methods, and clamp methods. Among them, the fiber composite material method requires divers to manually wind the composite material on the subsea pipeline. However, due to the limited underwater vision of divers, restricted movement in water, operation can only be carried out during a limited slack tide period, large water flow disturbance, extremely difficult operation, extremely high construction cost, and extremely long operation time. Similarly, the sleeve method, welding method, and clamp method also require varying degrees of manual participation and will face the same problems. Especially underwater welding has extremely high operation costs. Summary of the Invention

[0004] The purpose of the present invention is to provide a cavity medium replacement system and method suitable for subsea pipeline repair projects to solve the problems existing in the above-mentioned prior art. By replacing the water in the equipment with air, a dry environment is provided for subsequent subsea pipeline repair operations, thereby greatly reducing the construction cost and construction difficulty and shortening the operation time.

[0005] To achieve the above object, the present invention provides the following solutions:

[0006] The present invention provides a cavity medium replacement system applicable to subsea pipeline repair projects, including an air supply system, a valve panel, an equipment body, and a pumping system; the equipment body includes a floating cabin and an operation cabin, the air supply system is used to supply compressed air to the operation cabin and the floating cabin to replace the seawater in the cabins; the valve panel is used to control the on-off of each pipeline; the operation cabin of the equipment body is used to seal and surround the subsea pipeline to be repaired, and the seawater in the operation cabin and the floating cabin can be replaced with air, so as to provide a dry environment for subsequent repair operations; the pumping system is used to discharge the seawater in the operation cabin and the floating cabin out of the cabins, and cooperate with the air supply system to complete the replacement of seawater and air; the air supply system is located in a shaded and ventilated place on the ship's deck and is used to provide compressed air for the equipment body. Among them, the air supply pressure is greater than the water pressure of the environment where the equipment body is located, so as to send the compressed air into the equipment body and then squeeze out the seawater in the equipment body.

[0007] Optionally, the operation cabin includes a left half-cabin and a right half-cabin with the same structure and symmetrically arranged. The equipment body includes a bracket. The floating cabin is fixedly arranged at the top of the bracket. The inner side of the bracket is respectively hinged to the left half-cabin and the right half-cabin through hydraulic cylinders. After the left half-cabin and the right half-cabin are closed, it is a horizontally placed hexagonal prism-shaped cabin structure; both the front and rear end faces of the operation cabin are hexagonal planes, and circular through holes for holding the subsea pipeline are respectively opened in the middle of the front and rear end faces of the operation cabin; a sealing strip is embedded between the left half-cabin and the right half-cabin of the operation cabin, and a sealing strip is also embedded at the circular through hole of the operation cabin.

[0008] Optionally, the bracket is in a "door" shape structure. The floating cabin is fixedly arranged on the top of the upper cross beam of the bracket and is used to provide buoyancy, so as to reduce the force on the equipment body in the vertical direction in water. The bottom of the upper cross beam of the bracket is hinged to the top of the operation cabin through a rotating shaft; one end of the hydraulic cylinder is hinged to the middle of one side of the bracket, and the other end is hinged to the lower part of the left half-cabin or the right half-cabin and is used to control the opening and closing operations of the operation cabin.

[0009] Optionally, a butterfly valve is provided between the operation cabin and the floating cabin to control the on-off of the connection between the floating cabin and the operation cabin. The butterfly valve is connected to the operation cabin and the floating cabin respectively through rubber hoses. A three-way valve is provided outside the operation cabin, which is connected to the floating cabin, the pumping system and the outside world respectively to control the switching between the two paths of connecting the water pump to the floating cabin and the water pump to the outside world. A floating cabin check valve is connected to the top of the floating cabin to control the unidirectional flow of the gas in the floating cabin to the outside. A water collecting tank and an operation cabin check valve communicating with the outside are respectively provided at the bottom of the operation cabin. The water collecting tank is used to displace the water flow to the lowest point during the operation to facilitate the suction operation of the water pump. The operation cabin check valve is used to control the unidirectional outflow of the water in the cabin to the outside. The volume of the floating cabin is 1 / 2 of the volume of the operation cabin, so as to reduce the resultant force of the equipment body and the force exerted by the equipment body on the pipeline, thereby protecting the pipeline. When the equipment body is lowered, the floating cabin is filled with compressed air. At this time, the gravity of the equipment body is greater than the buoyancy, and the floating cabin is used to increase the buoyancy. Before the operation in the operation cabin, the floating cabin is filled with seawater and the operation cabin is filled with air. At this time, the buoyancy of the equipment body is greater than the gravity, and the floating cabin is used to increase the gravity.

[0010] Optionally, lifting lugs are provided at the four corner positions of the top of the floating cabin for bearing the lifting and lowering operations of the equipment.

[0011] Optionally, the pumping system includes a water pump, namely an electric sand-excluding submersible pump, with a flow rate of 100 m 3 / h and a head of 80 m, which is used in cooperation with a frequency converter to control the rotation speed of the water pump. A water pump fixing bracket is fixedly provided on the side wall inside the operation cabin, and the water pump is fixedly installed on the water pump fixing bracket. A liquid level sensor is provided on one side of the water pump to detect the water level in the cabin, and the liquid level signal is transmitted to the ship through an optical and electrical composite cable.

[0012] Optionally, the air supply system includes an air compressor, namely an air compressor, with a volumetric flow rate of 13 m 3 / min; The valve panel is used for the connection of the air pipe between the air compressor and the equipment body, the on-off control of the air circuit, and the pressure display of the equipment body; the valve panel includes five pipelines. The first pipeline of the valve panel is used for displaying the pressure of the floating cabin, including a second stop valve connected to the floating cabin. The second stop valve is connected to a first stop valve and a first pressure gauge through a second three-way joint; the second pipeline of the valve panel is used for displaying the pressure of the operation cabin, including a fourth stop valve connected to the operation cabin. The fourth stop valve is respectively connected to a third stop valve and a second pressure gauge through a third three-way joint; the third pipeline of the valve panel is used for inflating the floating cabin, including a fifth stop valve connected to the floating cabin. The fifth stop valve is respectively connected to a first three-way joint and a pressure gauge through a fourth three-way joint; the fourth pipeline of the valve panel is used for inflating the operation cabin, including a sixth stop valve connected to the operation cabin. The sixth stop valve is connected to a first three-way joint and a fourth pressure gauge through a fifth three-way joint; the fifth pipeline of the valve panel includes a seventh stop valve connecting the operation cabin and the outside; the first three-way joint is connected to the air compressor for exhausting air from the operation cabin. When the present invention works, first, the hydraulic cylinder fully contracts to open the operation cabin. The three-way valve is switched to connect the water pump to the outside, the butterfly valve is closed, and the lowering starts. The air compressor supplies air to the floating cabin until the gas inside the floating cabin overflows from the floating cabin through the floating cabin check valve, making the gas inside the floating cabin balance with the water pressure outside the floating cabin. Then continue to lower until the operation cabin is placed above the pipeline; the operation cabin is closed, the three-way valve is switched to connect the water pump to the floating cabin, the air compressor starts to inflate the operation cabin, the seawater inside the operation cabin is discharged to the seawater through the operation cabin check valve, and at the same time the water pump is turned on to pump water into the floating cabin until the floating cabin is full of water. The air compressor continuously inflates the operation cabin until the operation cabin is emptied; start the operation, after the operation is completed; the operation cabin exhausts air outward, the hydraulic cylinder intermittently contracts to open the operation cabin, allowing the seawater outside the cabin to pour into the operation cabin until the rising water level rises to half of the operation cabin; the diver opens the butterfly valve, the three-way valve is switched to connect the water pump to the outside, the air compressor supplies air to the floating cabin, the operation cabin exhausts air to the outside of the cabin, the water pump pumps water to the outside of the cabin, making the water in the floating cabin flow down to the operation cabin until it completely flows out, turn off the water pump, and the diver closes the butterfly valve; the hydraulic cylinder contracts, the operation cabin opens, allowing the seawater outside to pour into the operation cabin; after the operation cabin is fully opened, the present invention is lifted to complete the operation.

[0013] The present invention also provides a cavity medium replacement method applicable to the underwater pipeline repair project, including the following steps:

[0014] Step 1, lower the equipment body. First, the hydraulic cylinder fully contracts to open the left half cabin and the right half cabin of the operation cabin. The three-way valve is switched to connect the water pump to the outside, the butterfly valve is closed, and the lowering starts. The air compressor supplies air to the floating cabin until the gas inside the floating cabin overflows from the floating cabin through the floating cabin check valve, making the gas inside the floating cabin balance with the water pressure outside the floating cabin. Then continue to lower until the operation cabin is placed above the underwater pipeline;

[0015] Step 2: Close the operation cabin, open the hydraulic cylinder, close the left and right halves of the operation cabin, and embrace the submarine pipeline to be repaired between the left and right halves;

[0016] Step 3: Fill the floating cabin with water, inflate the operation cabin with an air compressor, and the operation cabin drains water into the floating cabin through a water pump until the floating cabin is full;

[0017] Step 4: Drain the operation cabin, continue to drain water from the operation cabin into the floating cabin until the operation cabin is emptied, and at the same time, the seawater in the floating cabin is discharged to the outside through the one-way valve of the floating cabin;

[0018] Step 5: Operate, perform underwater repair operations on the submarine pipeline;

[0019] Step 6: Drain the floating cabin. After the repair operation is completed, the operation cabin exhausts air to the outside, the hydraulic cylinder contracts intermittently to open the operation cabin, allowing seawater outside the cabin to pour into the operation cabin until the water level rises to half of the operation cabin; open the butterfly valve, switch the three-way valve to connect the water pump to the outside, the air compressor ventilates the floating cabin, the water pump pumps water out of the cabin, allowing the water in the floating cabin to flow into the operation cabin until it completely drains, then turn off the water pump and close the butterfly valve;

[0020] Step 7: Open and fill the operation cabin with water, the hydraulic cylinder contracts, the operation cabin opens, allowing seawater from the outside to pour into the operation cabin;

[0021] Step 8: Recover the equipment. After the operation cabin is fully opened, lift the equipment body to complete the operation.

[0022] The present invention has achieved the following technical effects compared with the prior art:

[0023] The present invention creatively proposes to use the operation cabin to hold the pipeline, and by replacing the gas and seawater in the operation cabin and the floating cabin, a dry environment is created, greatly reducing the difficulty of pipeline repair. The present invention designs a floating cabin to reduce the resultant force in water when the present invention is lowered, thereby reducing the force exerted on the pipeline when the present invention is located on the pipeline. The present invention fills compressed air into the floating cabin to balance the air pressure inside the floating cabin and the water pressure outside the floating cabin, thereby reducing the structural stress of the floating cabin. Description of the Drawings

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required to be used in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0025] Figure 1 It is a schematic diagram of the pipeline and valve connection of the cavity medium replacement system applicable to the submarine pipeline repair project of the present invention;

[0026] Figure 2 Schematic diagram of the external structure of the equipment body;

[0027] Figure 3 Schematic diagram of the internal structure of the equipment body;

[0028] Figure 4 Flow chart of the cavity medium replacement method applicable to the undersea pipeline repair project of the present invention;

[0029] Explanation of reference numerals: 1 air supply system, 2 valve panel, 3 equipment body, 3-1 butterfly valve, 3-2 rubber hose, 3-3 hydraulic cylinder, 3-4 water collecting tank, 3-5 floating tank check valve, 3-6 lifting lug, 3-7 floating tank, 3-8 three-way valve, 3-9 operation cabin check valve, 3-10 operation cabin, 3-11 support, 3-12 water pump fixing bracket, 3-13 liquid level sensor, 3-14 rotating shaft, 3-15 sealing strip, 4 water pumping system. Detailed implementation manners

[0030] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0031] The purpose of the present invention is to provide a cavity medium replacement system and method applicable to the undersea pipeline repair project to solve the problems existing in the above-mentioned prior art. By replacing the water in the equipment with air, a dry environment is provided for the subsequent repair operation of the undersea pipeline, thereby greatly reducing the construction cost and construction difficulty and shortening the operation time.

[0032] To make the above objects, features and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific implementation manners.

[0033] As Figure 1 shown, the present invention provides a cavity medium replacement system applicable to the undersea pipeline repair project, including an air supply system 1, a valve panel 2, an equipment body 3, and a water pumping system 4; wherein, the air supply system 1 is used to supply compressed air to the operation cabin 3-10 and the floating tank 3-7 to replace the seawater in the cabin; the valve panel 2 is used to control the on-off of each pipeline; the equipment body 3 is used to realize the replacement of seawater and air in the cabin, thereby providing a dry environment for the subsequent repair operation; the water pumping system 4 is used to drain the seawater in the operation cabin 3-10 out of the cabin and cooperate with the air supply system 1 to complete the replacement of seawater and air.

[0034] As Figure 2As shown in the figure, the exterior of the equipment body 3 includes a butterfly valve 3-1, a rubber hose 3-2, a hydraulic cylinder 3-3, a water collecting tank 3-4, a floating cabin check valve 3-5, a lifting lug 3-6, a floating cabin 3-7, a three-way valve 3-8, an operation cabin check valve 3-9, an operation cabin 3-10, and a bracket 3-11. Among them, the operation cabin 3-10 includes a left half cabin and a right half cabin. After being closed, it is a horizontally placed hexagonal prism-shaped cabin body. The front and rear end faces are hexagonal planes, and there is a circular through hole in the middle for clamping the submarine pipeline. The diameter of the circular through hole is the same as that of the submarine pipeline. The operation cabin 3-10 has the functions of opening and closing. A sealing strip 3-15 is embedded between the left and right half cabins of the operation cabin 3-10 to achieve the sealing between the left and right half cabins and the sealing between the operation cabin 3-10 and the submarine pipeline. The operation cabin 3-10 is used for repairing the submarine pipeline after the replacement operation is completed. The bracket 3-11 is a "door"-shaped square steel structure. The upper cross beam of the bracket 3-11 is hinged to the operation cabin 3-10 through a rotating shaft, and is used to support the operation cabin 3-10, the floating cabin 3-7, and the hydraulic cylinder 3-3, and to protect the operation cabin 3-10. The floating cabin 3-7 is fixed above the bracket 3-11 and is used to provide buoyancy, thereby reducing the force on the equipment body 3 in the vertical direction in water. The butterfly valve 3-1 is located between the floating cabin 3-7 and the operation cabin 3-10, and connects the floating cabin 3-7 and the operation cabin 3-10 through the rubber hose 3-2, and is used to control the on-off of the connection between the floating cabin 3-7 and the operation cabin 3-10; the three-way valve 3-8 is located outside the operation cabin 3-10 and connects the floating cabin 3-7, the water pump outlet and the outside world, and is used to control the conversion of the two paths of connection between the water pump and the floating cabin 3-7 and the water pump and the outside world; one end of the hydraulic cylinder 3-3 is fixed to the middle of the bracket 3-11, and the other end is hinged to the lower part of the operation cabin 3-10, and is used to control the opening and closing operations of the operation cabin 3-10; the water collecting tank 3-4 is located at the bottom of the operation cabin 3-10 and is used to displace the water flow in the operation cabin to the lowest point, facilitating the pumping operation of the water pump; the lifting lugs 3-6 are located at the four corners of the floating cabin 3-7 and are used for the lifting of the equipment and the bearing of the downward operation; the operation cabin 3-10 check valve 3-9 is located at the bottom of the operation cabin 3-10 and is used to control the water in the cabin to flow out of the cabin only unidirectionally; the floating cabin 3-7 check valve 3-5 is located at the top of the floating cabin 3-7 and is used to control the gas in the floating cabin 3-7 to flow unidirectionally to the outside;

[0035] As Figure 3As shown in the figure, the interior of the equipment body 3 includes a water pump fixing bracket 3-12, a liquid level sensor 3-13, a rotating shaft 3-14, and a sealing strip 3-15. The water pump fixing bracket 3-12 is fixed to the side wall of the operation cabin 3-10 and is used to fix the water pump. The liquid level sensor 3-13 is fixed beside the water pump and is used to detect the water level in the cabin. The liquid level signal is transmitted to the ship through an optical and electrical composite cable. The rotating shaft 3-14 is located at the top of the operation cabin 3-10 and is used to hinge the bracket 3-11 and the operation cabin 3-10. The sealing strip 3-15 is made of rubber and is located at the longitudinal and transverse joints of the left and right half cabins of the operation cabin 3-10, and is used to perform the sealing operation after the operation cabin 3-10 hugs the pipeline.

[0036] As Figure 4 shown, the method for replacing the cavity medium in the subsea pipeline repair project is as follows: First, the operation cabin 3-10 opens, and the equipment body 3 is lowered until it touches the subsea pipeline. Then, the hydraulic cylinder 3-3 extends, the operation cabin 3-10 closes, and the operation cabin 3-10 drains water into the floating cabin 3-7 until the floating cabin 3-7 is full of water. The operation cabin 3-10 continues to drain water into the floating cabin 3-7 until the operation cabin 3-10 is emptied, and the seawater in the floating cabin 3-7 is discharged to the outside through the one-way valve 3-5 of the floating cabin 3-7. The repair operation starts. After the repair operation is completed, the water in the floating cabin 3-7 is discharged into the operation cabin 3-10 until the floating cabin 3-7 is filled with compressed air. The operation cabin 3-10 fully opens. The equipment is lifted and recovered.

[0037] Combined with Figure 1 , the connection relationships between each pipeline and valve on the valve panel of the replacement system of the present invention and the air supply system, the equipment body, and the pumping system are as Figure 1 shown. The air compressor of the air supply system is connected to the floating cabin of the equipment body through the first three-way joint, the fourth three-way joint, and the fifth stop valve. The air compressor of the air supply system is connected to the operation cabin of the equipment body through the first three-way joint, the fifth three-way joint, and the sixth stop valve. The floating cabin is connected to the outside through the second stop valve, the second three-way joint, and the first stop valve. The operation cabin is connected to the outside through the fourth stop valve, the third three-way joint, and the third stop valve. The operation cabin is also externally connected with a seventh stop valve. A first pressure gauge is connected to the second three-way joint, a second pressure transducer is connected to the third three-way joint, a third pressure gauge is connected to the fourth three-way joint, and a fourth pressure gauge is connected to the fifth three-way joint. The floating cabin is respectively connected to the operation cabin through a butterfly valve and a three-way valve. The three-way valve and the operation cabin are respectively connected to the water pump of the pumping system. Based on Figure 1 the connection method of each valve and pipeline, an example of the usage method of the replacement system of the present invention is as follows:

[0038] (1) Hoisting operation

[0039] After the ship arrives at the construction sea area, lock the hook of the ship's crane to the lifting lug 3-6, turn on the air supply system 1, fill the floating cabin 3-7 with air, open the operation cabin 3-10, close the butterfly valve 3-1, and switch the three-way valve 3-8 to connect the pumping system to the outside world. Open the second stop valve, the fourth stop valve, and the fifth stop valve, and close the first stop valve, the third stop valve, the sixth stop valve, and the seventh stop valve. At this time, the air supply system 1 supplies air to the floating cabin 3-7. Every time it is lowered by 5m, stop lowering. When compressed air overflows from the check valve 3-5 of the floating cabin 3-7 and bubbles appear on the water surface, continue to lower the equipment until the equipment is placed on the submarine pipeline.

[0040] (2) Close the operation cabin 3-10

[0041] The hydraulic cylinder 3-3 extends to close the operation cabin 3-10.

[0042] (3) Fill the floating cabin 3-7 with water

[0043] The diver switches the three-way valve 3-8 to connect the pumping system to the floating cabin 3-7. Open the second stop valve, the fourth stop valve, and the sixth stop valve, and close the first stop valve, the third stop valve, the fifth stop valve, and the seventh stop valve. At this time, the air supply system 1 supplies air to the operation cabin 3-10, the air supply system 1 stops supplying air to the floating cabin 3-7, the pumping system is turned on, and water is pumped into the floating cabin 3-7 until the floating cabin 3-7 is full of water.

[0044] (4) Drain the water from the operation cabin 3-10

[0045] The pumping system remains on and pumps water into the floating cabin 3-7. The seawater in the floating cabin 3-7 floods into the outside world through the check valve 3-5 of the floating cabin 3-7 until the liquid level sensor 3-13 shows that there is no water in the cabin.

[0046] (5) Operation

[0047] Carry out repair operations.

[0048] (6) Drain the water from the floating cabin 3-7

[0049] The hydraulic cylinder 3-3 slightly contracts to slightly open the operation cabin 3-10, allowing seawater outside the cabin to flood into the operation cabin 3-10 until the water level rises to half and then close the operation cabin 3-10. The diver switches the three-way valve 3-8 to connect the pumping system to the outside world and opens the butterfly valve 3-1. Open the second stop valve, the fourth stop valve, the fifth stop valve, and the seventh stop valve, and close the first stop valve, the third stop valve, and the sixth stop valve. At this time, the air supply system 1 supplies air to the floating cabin 3-7, the air supply system stops supplying air to the operation cabin 3-10, and the operation cabin 3-10 exhausts air to the water surface. Then the pumping system is turned on to discharge the seawater in the operation cabin 3-10 to the outside world, and the seawater in the floating cabin 3-7 floods into the operation cabin 3-10 to complete the replacement of the seawater in the floating cabin 3-7 with the seawater in the operation cabin 3-10. Then the diver closes the butterfly valve 3-1 to prevent seawater from flooding into the floating cabin 3-7 from the operation cabin 3-10.

[0050] (7) The operation cabin 3-10 opens and is filled with water

[0051] The hydraulic cylinder 3-3 fully retracts to fully open the operation cabin 3-10, allowing seawater to fully pour in.

[0052] (8) Equipment recovery

[0053] The shipboard crane retracts the lifting cable upward, and the equipment is disengaged from the subsea pipeline.

[0054] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "top", "bottom", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0055] Specific examples are applied in the present invention to elaborate on the principle and implementation manner of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention; at the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. A cavity medium replacement method applicable to subsea pipeline repair projects, characterized in that: A cavity medium replacement system applicable to subsea pipeline repair projects is adopted. The cavity medium replacement system applicable to subsea pipeline repair projects includes an air supply system, a valve panel, an equipment body, and a pumping system; the equipment body includes a floating cabin and an operation cabin. The air supply system is used to provide compressed air to the operation cabin and the floating cabin to replace the seawater in the cabins; the valve panel is used to control the on-off of each pipeline; the operation cabin of the equipment body is used to seal and surround the subsea pipeline to be repaired, and the seawater in the operation cabin and the floating cabin can be replaced with air, so as to provide a dry environment for subsequent repair operations; the pumping system is used to drain the seawater in the operation cabin and the floating cabin out of the cabins, and cooperate with the air supply system to complete the replacement of seawater and air; the cavity medium replacement method applicable to subsea pipeline repair projects includes the following steps: Step 1, lowering the equipment body. First, the hydraulic cylinder is fully retracted, the left and right halves of the operation cabin are opened, the three-way valve is switched to connect the water pump to the outside, the butterfly valve is closed, and lowering starts. The air compressor supplies air to the floating cabin until the internal gas of the floating cabin overflows from the floating cabin through the floating cabin check valve, so that the internal gas of the floating cabin is balanced with the external water pressure of the floating cabin, and then continue to lower until the operation cabin is placed above the subsea pipeline; Step 2, closing the operation cabin. The hydraulic cylinder is opened, the left and right halves of the operation cabin are closed, and the subsea pipeline to be repaired is surrounded between the left and right halves; Step 3, filling the floating cabin with water. The air compressor fills the operation cabin with air, and the operation cabin drains water into the floating cabin through the water pump until the floating cabin is full of water; Step 4, draining the operation cabin. The operation cabin continues to drain water into the floating cabin until the operation cabin is emptied, and at the same time, the seawater in the floating cabin is discharged to the outside through the floating cabin check valve; Step 5, operation. Carry out underwater repair operations on the subsea pipeline; Step 6, draining the floating cabin. After the repair operation is completed, the operation cabin exhausts air to the outside, and the hydraulic cylinder contracts intermittently to open the operation cabin, so that the seawater outside the cabin surges into the operation cabin until the water level rises to half of the operation cabin; Open the butterfly valve, switch the three-way valve to connect the water pump to the outside, the air compressor supplies air to the floating cabin, the water pump pumps water out of the cabin, so that the water in the floating cabin flows into the operation cabin until it completely flows out, turn off the water pump, and close the butterfly valve; Step 7, opening and filling the operation cabin with water. The hydraulic cylinder contracts, the operation cabin opens, and the seawater outside is allowed to surge into the operation cabin; Step 8, recovering the equipment. After the operation cabin is fully opened, lift the equipment body to complete the operation.

2. The cavity medium replacement method applicable to subsea pipeline repair projects according to claim 1, characterized in that: The operation cabin includes a left half-cabin and a right half-cabin with the same structure and symmetrically arranged. The equipment body includes a bracket, and a floating cabin is fixedly arranged at the top of the bracket. The inner side of the bracket is respectively hinged to the left half-cabin and the right half-cabin through hydraulic cylinders. After the left half-cabin and the right half-cabin are closed, it forms a horizontally placed hexagonal columnar cabin structure; both the front and rear end faces of the operation cabin are hexagonal planes, and circular through-holes for holding the submarine pipeline are respectively opened in the middle of the front and rear end faces of the operation cabin; a sealing strip is embedded between the left half-cabin and the right half-cabin of the operation cabin, and a sealing strip is also embedded at the circular through-hole of the operation cabin.

3. The method for cavity medium replacement applicable to submarine pipeline repair projects according to claim 2, characterized in that: The bracket is in a "door" - shaped structure, the floating cabin is fixedly arranged at the top of the upper crossbeam of the bracket, and the bottom of the upper crossbeam of the bracket is hinged to the top of the operation cabin through a rotating shaft; one end of the hydraulic cylinder is hinged to the middle of one side of the bracket, and the other end is hinged to the lower part of the left half-cabin or the right half-cabin.

4. The method for cavity medium replacement applicable to submarine pipeline repair projects according to claim 2, characterized in that: A butterfly valve is arranged between the operation cabin and the floating cabin, and the butterfly valve is respectively communicated with the operation cabin and the floating cabin through rubber hoses; a three-way valve is arranged outside the operation cabin, and the three-way valve is respectively communicated with the floating cabin, the pumping system and the outside; a floating cabin check valve is connected to the top of the floating cabin, and a water collecting tank and an operation cabin check valve communicated with the outside are respectively arranged at the bottom of the operation cabin.

5. The method for cavity medium replacement applicable to submarine pipeline repair projects according to claim 2, characterized in that: Lifting lugs are arranged at the four corner positions of the top of the floating cabin.

6. The method for cavity medium replacement applicable to submarine pipeline repair projects according to claim 2, characterized in that: The pumping system includes a water pump; a water pump fixing bracket is fixedly arranged on the side wall inside the operation cabin, and the water pump is fixedly installed on the water pump fixing bracket; a liquid level sensor is arranged on one side of the water pump.

7. The method for cavity medium replacement applicable to submarine pipeline repair projects according to claim 1, characterized in that: The air supply system includes an air compressor; the valve panel is used for connecting the air pipe between the air compressor and the equipment body, controlling the on / off of the air circuit, and displaying the pressure of the equipment body; the valve panel includes five pipelines. The first pipeline of the valve panel includes a stop valve II connected to the floating cabin, and the stop valve II is connected to a stop valve I and a pressure gauge I through a tee joint II; the second pipeline of the valve panel includes a stop valve IV connected to the operation cabin, and the stop valve IV is respectively connected to a stop valve III and a pressure gauge II through a tee joint III; the third pipeline of the valve panel is a stop valve V connected to the floating cabin, and the stop valve V is respectively connected to a tee joint I and a pressure gauge through a tee joint IV; the fourth pipeline of the valve panel includes a stop valve VI connected to the operation cabin, and the stop valve VI is connected to the tee joint I and a pressure gauge IV through a tee joint V; the fifth pipeline of the valve panel includes a stop valve VII connecting the operation cabin and the outside; the tee joint I is connected to the air compressor.

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