System and method for salvaging deep-buried submarine cables

Abstract

A system and method for salvaging a deep-buried submarine cable, comprising: a surface monitoring power station and an underwater salvage platform connected thereto via an umbilical cable, wherein: the surface monitoring power station provides strong electric power and monitoring information transmission to the underwater salvage platform via the umbilical cable; the surface monitoring power station remotely controls the underwater salvage platform to realize the exploration, positioning, spraying and desilting, grabbing and lifting of the deep-buried submarine cable, until the deep-buried cable is safely salvaged to the mud surface or water surface for subsequent treatment. The present invention is used for salvaging cables buried deep under mud on the seabed, and has the characteristics of comprehensive functions, easy use, and low environmental damage.

Description

Technical Field

[0001] The present invention relates to a deep-sea salvage technology, in particular to a deep-sea cable salvage system and method. Background Art

[0002] In the underwater emergency rescue, deep sea salvage or offshore oil and gas industries, the search and salvage of deeply buried underwater objects, such as submarine oil and gas pipelines, submarine optical cables, etc., are often involved. The salvage of deep buried submarine cables is affected by the surrounding silt, and there are problems such as difficulty in finding the target, difficulty in excavation, and high construction risks. Existing submarine cable salvage technologies mostly use a nearly pure mechanical method, which is only suitable for the salvage of submarine surface or shallowly buried cables. At the same time, it is necessary to obtain accurate target location and depth information in advance. At the same time, due to the large disturbance of the soil caused by the operation method, it is impossible to solve the problem of soil collapse when salvaging soil such as silt. Summary of the invention

[0003] In view of the above-mentioned deficiencies in the prior art, the present invention proposes a system and method for recovering deep-buried submarine cables, which uses an unmanned remotely operated vehicle (ROV) floating platform, a specially designed cable hook to explore and hook the deeply buried cable under the mud, a movable jet mechanism to clear the silt around the cable, and a cable hoist to grab and lift the cable to the mud surface or water surface. The present invention is aimed at recovering cables buried deep under the mud on the seabed, and has the characteristics of comprehensive functions, easy use, and little damage to the environment.

[0004] It has the functions of detecting deeply buried cables, clearing silt and salvaging cables.

[0005] The present invention is achieved through the following technical solutions:

[0006] The present invention relates to a submarine deep-buried cable salvage system, comprising: a surface monitoring power station and an underwater salvage platform connected to the surface monitoring power station via an umbilical cable, wherein: the surface monitoring power station provides strong electric power and monitoring information transmission to the underwater salvage platform via the umbilical cable; the surface monitoring power station remotely controls the underwater salvage platform to realize the detection, positioning, spraying and desilting, grabbing and lifting of the submarine deep-buried cable, until the deep-buried cable is safely salvaged to the mud surface or water surface for subsequent processing.

[0007] The surface monitoring power station includes: a power system, a control system, a power supply unit and a monitoring and control unit arranged in a container, wherein: the power supply unit is connected to the power system through a power channel inside the umbilical cable to provide strong electric power for underwater system operations; the monitoring and control unit is connected to the control system through a communication channel inside the umbilical cable to receive sensor data and transmission control instructions from the control system.

[0008] The underwater salvage platform comprises: a main frame and buoyancy materials, a thruster, an underwater hydraulic system, an underwater electric control system, a pressure compensation system, a cable hook, a movable jet mechanism, a cable hoist, and a jet system, wherein: the underwater hydraulic system is connected to the thruster, the cable hook, the movable jet mechanism and the cable hoist through oil pipes to provide hydraulic power and control; the underwater electric control system is connected to the surface monitoring power station, the underwater hydraulic system and the underwater sensor through cables to collect data from each underwater sensor and transmit it to the surface through an umbilical cable, while receiving surface control instructions to realize motion control of the underwater salvage platform and operation control of each salvage tool; the pressure compensation system is connected to the underwater electric control system and the underwater hydraulic system to provide pressure compensation to maintain internal and external pressure balance.

[0009] Technical Effects

[0010] The present invention utilizes a specially designed cable hook, a movable spraying mechanism and a cable lifting device in conjunction with an unmanned remotely operated vehicle (ROV) floating platform to realize the functions of exploring, locating, dredging, grabbing and lifting and salvaging cables buried deep under mud. The specially designed cable lifting device structure can adapt to a larger grabbing range and effectively protect the cable from damage during operation; the movable spraying mechanism expands the silt cleaning range of the submarine cable while reducing the overall scale of the platform. The present invention can perform underwater cable salvage operations in an environment with a water depth of more than 100 meters, the salvage depth under mud can reach 4 meters, and the amount of ground breaking and excavation is reduced by at least 60-70%. The operation efficiency, the impact on the underwater environment and the protection effect on the cable are significantly higher than the conventional operation method of full excavation. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a schematic diagram of the present invention;

[0012] Figure 2 It is the general arrangement drawing of the underwater salvage platform;

[0013] Figure 3 Main frame state diagram;

[0014] Figure 4 It is a schematic diagram of the cable hook and movable jetting mechanism;

[0015] Figure 5 This is an enlarged schematic diagram of the hook and cable device;

[0016] Figure 6 It is an enlarged schematic diagram of the movable jetting mechanism;

[0017] Figure 7 This is a schematic diagram of a cable hoist;

[0018] In the figure: (a) is the initial state; (b) is the lowering state; (c) is the state of the hand gripping the cable; (d) is the state of the hand gripping the cable and closing it; (e) is the state of lifting it after gripping the cable;

[0019] Figure 8 It is a schematic diagram of the cable sounding mechanism;

[0020] Fig. 9 This is a schematic diagram of the jet flushing system;

[0021] Fig.10 It is a schematic diagram of the working state of the present invention;

[0022] In the figure: (a) is the bottom-sitting state; (b) is the probing state of the cable hook; (c) is the state after the movable jetting mechanism is lowered; (d) and (e) are the clearing states of the movable jetting mechanism; (f) is the state of the cable hoist grabbing the cable; (g) is the state after the cable hook is retrieved; (h) is the state of the cable entering the bayonet after being lifted; (i) is the state of the wire being lifted out of the mud surface. DETAILED DESCRIPTION

[0023] like Figure 1 As shown, this embodiment involves a submarine deep-buried cable salvage system, including: a surface monitoring power station and an underwater salvage platform connected to the surface via an umbilical cable, wherein: the surface monitoring power station provides strong electric power and monitoring information transmission to the underwater salvage platform via the umbilical cable; the surface monitoring power station remotely controls the underwater salvage platform to achieve detection, positioning, spraying and dredging, grabbing and lifting of the submarine deep-buried cable until the deep-buried cable is safely salvaged to the mud surface or water surface for subsequent processing.

[0024] The surface monitoring power station stores and retracts the umbilical cable via a winch.

[0025] The surface monitoring power station includes: a power system, a control system, a power supply unit and a monitoring and control unit arranged in a container, wherein: the power supply unit is connected to the power system through a power channel inside the umbilical cable to provide strong electric power for underwater system operations; the monitoring and control unit is connected to the control system through a communication channel inside the umbilical cable to receive sensor data and transmission control instructions from the control system.

[0026] like Figure 2 and Figure 4As shown, the underwater salvage platform includes: a main frame 1 and buoyancy materials 2 arranged thereon, a thruster 3, an underwater hydraulic system, an underwater electric control system, a pressure compensation system, a pair of cable hooks 7, a pair of movable jet mechanisms 8, a pair of cable hoists 9 and a jet system 10, wherein: the underwater hydraulic system is connected to the thruster, the cable hook, the movable jet mechanism and the cable hoist through oil pipes to provide hydraulic power and control; the underwater electric control system is connected to the surface monitoring power station, the underwater hydraulic system and the underwater sensor through cables to collect data from each underwater sensor and transmit it to the surface through the umbilical cable, and at the same time receives surface control instructions to realize the motion control of the underwater salvage platform and the operation control of each salvage tool; the pressure compensation system is connected to the underwater electric control system and the underwater hydraulic system to provide pressure compensation to keep the internal and external pressures balanced.

[0027] The pair of cable hooks, a pair of cable lifting devices and a pair of movable spraying mechanisms are symmetrically arranged from the center to both sides of the main frame.

[0028] like Figure 3 As shown, the main frame 1 includes: a top structure 101, a middle structure 102, a hanging point 103 and a bottom slide 104, wherein: the hanging point 103 is arranged on the top structure 101, the middle structure 102 is provided with tools, mechanisms and various subsystem components, and the bottom slide 104 is connected to the middle structure 102 through a mechanical installation interface, and contacts with the seabed during operation to reduce the sliding resistance and reduce the ground pressure.

[0029] The top structure 101 is provided with buoyancy material and a vertical thruster.

[0030] The slide 104 has a bayonet and a slide groove 105 in the middle. When sliding, the slide groove is closed to reduce sliding resistance. When lifting the cable, the slide groove is opened, and the slide groove is closed after the cable passes through the bayonet to prevent the cable from falling off.

[0031] like Figure 5 As shown, the cable hook 7 includes: a mounting support 11 and a hook-shaped structure 12, a nozzle 13, a driving cylinder 14 and a pipeline interface 15 arranged thereon, wherein: the mounting support is arranged as a swing arm structure, so as to increase the working depth of the hook-shaped structure under the mud; the hook-shaped structure is hollow inside and is connected to the spraying system through a pipeline interface, and the end of the structure is arranged in a hook shape or a semicircular arc shape, which can hook the cable upward to play a fixing role; a plurality of groups of nozzles are arranged on the outside of the hook-shaped structure, and the nozzles are connected to the internal high-pressure spraying water, which can form a jet to break the soil outward; a sensor is installed on the contact surface between the hook-shaped structure and the cable, and the position information of the cable relative to the hook-shaped device is obtained by using the principles of force induction, electromagnetic induction, etc.; the hook-shaped structure is rotated in the range of 0-90 degrees by extending and retracting the driving cylinder to cover different working depths.

[0032] The cable hook has the functions of jetting and breaking soil, cable detection and cable fixing, wherein: the cable hook can penetrate into the mud as a whole and move under the towing of the underwater salvage platform; the contact surface has a detection sensor, which can detect and sense the position of the cable and transmit the information to the underwater salvage platform control system; one or more groups of fixed or telescopic hook-shaped structures can be set at the end or middle position, which can hook the cable during jetting and dredging to prevent it from sinking under the action of gravity. After the jetting and dredging is completed and the cable hoist grabs the cable, the cable hook can be recovered and the hook-shaped structure is automatically separated from the cable.

[0033] like Figure 6 As shown, the movable spraying mechanism 8 includes: a movable guide rail 16, an arm-like structure 17, a nozzle 18, a pipeline interface 19 and a driving cylinder 20, wherein: the arm-like structure is a hollow structure and is connected to the spraying system through a pipeline interface, and multiple groups of nozzles are arranged on the outside of the arm-like structure and communicate with the high-pressure spraying water inside the arm-like structure, thereby forming a multi-directional and large-scale spraying and breaking the earth outward; the movable guide rail is arranged on the main frame of the underwater salvage platform, connected to the arm-like structure and carries the arm-like structure to reciprocate as a whole; the arm-like structure is rotated in the range of 0-90 degrees by the extension and contraction of the driving cylinder to cover different working depths.

[0034] The movable spraying mechanism can reciprocate along the axial direction of the cable after driving the oil cylinder to rotate to a specified angle (depth), and can perform large-scale dredging around the cable by continuous spraying.

[0035] like Figure 7 As shown in (a)-(e), the cable hoist 9 includes: a lifting rail 21, a claw mechanism 22, a cable feeler mechanism 23 and a driving cylinder 24, wherein: the lifting rail 21 is a multi-stage telescopic structure that can move up and down and is driven by the driving cylinder 24, and the end of the lifting rail 21 is connected to the claw mechanism 22; the cable feeler mechanism 23 is arranged under the claw mechanism 22 and is used to control the claw mechanism 22 to stop closing after being triggered to prevent over-grasping.

[0036] The gripper of the gripper mechanism 22 adopts a crossable involute structure, and is coated with organic materials such as nylon on the surface to reduce lifting friction resistance and not easily damage the outer surface of the cable. The end of the gripper is connected to the base of the gripper mechanism 22 through a bearing and a slip ring.

[0037] The gripper mechanism 22 is in a fully open state before being lowered, and is cross-closed after being lowered until the cable is embraced. During the cross-closing of the grippers, the cable moves up with the intersection to achieve a position lift, and the lifting mechanism lifts the cable until it is lifted out of the mud surface.

[0038] like Figure 8As shown, the cable probing mechanism 23 includes: a bottom plate 25, a bottom plate floating spring 26, a sensor support 27, a guide rod 28, a reset spring 29 and a sensor 30, wherein: the bottom plate is movably connected to the gripper mechanism 22 through a floating spring, and the bottom plate can move upward and reset itself after contacting the cable; the sensor, the guide rod and the reset spring are sequentially mounted on the sensor support, and the guide rod moves up and down with the bottom plate under the action of the reset spring and triggers the sensor; the sensor is connected to the underwater control system through a cable, and the sensing information is transmitted to the surface monitoring system in real time.

[0039] The sensor adopts the principle of electromagnetic induction, mechanical switch or other position sensing sensor.

[0040] like Fig. 9 As shown, the jet flushing system 10 includes: a manifold 31 and a jet flushing pump 32, a pipeline 33 and a switching valve 34 connected thereto, wherein: the jet flushing pump outlet is connected to the hook cable device, the movable jet flushing mechanism, and the cable lifting device through a pipeline, and a water circuit control valve, such as a check valve and a stop valve, is connected in series in the middle of the pipeline.

[0041] like Fig.10 As shown in (a)-(i), this embodiment relates to a method for salvaging a deep-buried submarine cable of the above system, comprising:

[0042] Step 1: Position the mother ship above the operation area and lower the underwater salvage platform into the water;

[0043] Step 2: Plan the cable exploration route. The underwater salvage platform uses thrusters to maneuver underwater, adjusts the longitudinal centerline to coincide with the exploration route, and sits on the bottom;

[0044] Step 3: Turn on the spray system, lower the cable hook to a 90-degree angle, and let the underwater salvage platform patrol the bottom. Use the cable hook’s induction sensor to detect the cable until both cable hooks detect the cable.

[0045] Step 4: Lower the movable spraying mechanism and start reciprocating spraying to clean the silt above and on both sides of the cable;

[0046] Step 5: Gradually lower the cable hoist to the specified depth and close the claws. After confirming that both sets of cable hoist claws have fully grasped the cable, stop closing the claws;

[0047] Step 6: Retract the mobile jetting mechanism to the initial position, and under the gripping state of the cable lifting claw, retract the guide rail drive cylinder step by step and synchronously to lift the cable out of the trench bottom;

[0048] Step 7: After all the guide rails of the cable hoist have returned to their original positions, the two sets of claws continue to close alternately at the same time until the feeler device on the top of the claws senses the position of the cable and the claws are in a fully closed state. At this time, the cable has been unearthed and entered the card position.

[0049] Step 8: Tie a float or buoy to the cable at the mud discharge section to keep it floating in the water;

[0050] Step 9: The cable lifting claws are fully opened and the mud section cable is released. The underwater salvage platform moves to the next excavation point and repeats the above steps;

[0051] Step 10: Use the cable hoist to grab the middle of the excavated cable, and the underwater salvage platform carries the cable as a whole and floats up and recovers it to the deck.

[0052] After actual platform experiments, it was found that in an environment with a water depth of more than 100 meters, the underwater cable salvage operation was carried out using tools carried out on an unmanned submersible platform. The underwater excavation depth could reach 4 meters, and the amount of excavation was reduced by at least 60-70%. The operation efficiency and protection of the underwater environment were significantly higher than the conventional full excavation operation method.

[0053] Compared with the prior art, the present invention adopts ROV submersible platform technology to integrate cable detection, jetting and breaking soil, grabbing and salvage operations. The specially designed cable hook adopts a contact sensor to directly and accurately sense the cable depth and position information, and combined with a professional jetting and breaking soil system and a cable hoist, it can dig deep into the mud and lock the cable to be salvaged. The operation integration and salvage accuracy are high, the damage to the environment is small, and it is more conducive to protecting the cable from damage.

[0054] The above-mentioned specific implementation can be partially adjusted in different ways by those skilled in the art without departing from the principle and purpose of the present invention. The protection scope of the present invention shall be based on the claims and shall not be limited by the above-mentioned specific implementation. Each implementation scheme within its scope shall be subject to the constraints of the present invention.

Claims

1. A submarine deep-buried cable salvage system, characterized in that: include: The surface monitoring power station and the underwater salvage platform connected to it through the umbilical cable, wherein: the surface monitoring power station provides strong electric power and monitoring information transmission to the underwater salvage platform through the umbilical cable; the surface monitoring power station remotely controls the underwater salvage platform to realize the exploration, positioning, spraying and desilting, grabbing and lifting of the deep-buried cables on the seabed, until the deeply buried cables are safely salvaged to the mud surface or water surface for subsequent processing; The surface monitoring power station includes: a power system, a control system, a power supply unit and a monitoring and control unit arranged in a container, wherein: the power supply unit is connected to the power system through a power channel inside the umbilical cable to provide strong electric power for underwater system operations; the monitoring and control unit is connected to the control system through a communication channel inside the umbilical cable to receive sensor data and transmission control instructions from the control system; The underwater salvage platform includes: a main frame and buoyancy materials, a thruster, an underwater hydraulic system, an underwater electric control system, a pressure compensation system, a cable hook, a movable jet mechanism, a cable hoist, and a jet system, wherein: a pair of cable hooks, a pair of cable hoists and a pair of movable jet mechanisms are symmetrically arranged from the center to both sides of the main frame, the underwater hydraulic system is connected to the thruster, the cable hook, the movable jet mechanism and the cable hoist through oil pipes, respectively, to provide hydraulic power and control; the underwater electric control system is connected to the surface monitoring power station, the underwater hydraulic system and the underwater sensor through cables, collects data from each underwater sensor and transmits it to the surface through an umbilical cable, and at the same time receives surface control instructions to realize motion control of the underwater salvage platform and operation control of each salvage tool; the pressure compensation system is connected to the underwater electric control system and the underwater hydraulic system, respectively, to provide pressure compensation to keep the internal and external pressures balanced.

2. The deep-buried submarine cable salvage system according to claim 1 is characterized in that: The main frame includes: a top structure, a middle structure, a hanging point and a bottom slide, wherein: the hanging point is set on the top structure, the middle structure is provided with tools, mechanisms and subsystem components, the bottom slide is connected to the middle structure through a mechanical installation interface, and contacts with the seabed during operation to reduce sliding resistance and reduce ground pressure.

3. The submarine deep-buried cable salvage system according to claim 1 is characterized in that: The cable hook comprises: a mounting support and a hook-shaped structure, a nozzle, a driving oil cylinder and a pipeline interface arranged thereon, wherein: the mounting support is arranged as a swing arm structure, thereby increasing the depth of the hook-shaped structure to work under the mud; the hook-shaped structure is hollow inside and is connected to the spraying system through a pipeline interface, and the end of the structure is arranged in a hook shape or a semicircular arc shape, which can hook the cable upwards to play a fixing role; a plurality of groups of nozzles are arranged outside the hook-shaped structure, and the nozzles are connected to the internal high-pressure spraying water to form a jet to break the soil outward; a sensor is installed on the contact surface between the hook-shaped structure and the cable, and the position information of the cable relative to the hook-shaped device is obtained by using the principles of force induction, electromagnetic induction, etc.; the hook-shaped structure is rotated within a range of - degrees by extending and retracting the driving oil cylinder to cover different working depths; The cable hook has the functions of jetting and breaking soil, cable detection and cable fixing, wherein: the cable hook can penetrate into the mud as a whole and move under the towing of the underwater salvage platform; the contact surface has a detection sensor, which can detect and sense the position of the cable and transmit the information to the underwater salvage platform control system; one or more groups of fixed or telescopic hook-shaped structures can be set at the end or middle position, which can hook the cable during jetting and dredging to prevent it from sinking under the action of gravity. After the jetting and dredging is completed and the cable hoist grabs the cable, the cable hook can be recovered and the hook-shaped structure is automatically separated from the cable.

4. The deep-buried submarine cable salvage system according to claim 1 is characterized in that: The movable spraying mechanism comprises: a movable guide rail, an arm-like structure, a nozzle, a pipeline interface and a driving oil cylinder, wherein: the arm-like structure is a hollow structure and is connected to the spraying system through a pipeline interface, and multiple groups of nozzles are arranged on the outside of the arm-like structure and communicate with the high-pressure spraying water inside the arm-like structure, thereby forming a multi-directional and large-scale spraying and breaking the earth outward; the movable guide rail is arranged on the main frame of the underwater salvage platform, connected to the arm-like structure and carries the arm-like structure to reciprocate as a whole; the arm-like structure is rotated within a range of - degrees by the extension and contraction of the driving oil cylinder to cover different working depths; The movable spraying mechanism can reciprocate along the axial direction of the cable after driving the oil cylinder to rotate to a specified angle or depth, and can perform large-scale silt removal around the cable by continuous spraying.

5. The submarine deep-buried cable salvage system according to claim 1 is characterized in that: The cable hoist comprises: a lifting guide rail, a claw mechanism, a cable feeler mechanism and a driving cylinder, wherein: the lifting guide rail is a multi-stage telescopic structure driven by the driving cylinder and can move up and down, and the end of the lifting guide rail is connected to the claw mechanism; the cable feeler mechanism is arranged under the claw mechanism to control the claw mechanism to stop closing after being triggered to prevent over-grasping.

6. The deep-buried submarine cable salvage system according to claim 5 is characterized in that: The gripper of the gripper mechanism adopts a crossable involute structure, and the surface is coated with organic materials such as nylon to reduce the lifting friction resistance and not easily damage the outer surface of the cable. The end of the gripper is connected to the base of the gripper mechanism through a bearing and a slip ring. The gripper mechanism is in a fully open state before being lowered, and after being lowered, it crosses and closes until the cable is embraced. During the cross-closing of the grippers, the cable moves up with the intersection to achieve a position lift, and the lifting mechanism lifts the cable until it is lifted out of the mud surface.

7. The deep-buried submarine cable salvage system according to claim 5 is characterized in that: The cable probing mechanism comprises: a bottom plate, a bottom plate floating spring, a sensor support, a guide rod, a reset spring and a sensor, wherein: the bottom plate is dynamically connected to the gripper mechanism through the floating spring, and the bottom plate can move upward and reset itself after contacting the cable; the sensor, the guide rod and the reset spring are sequentially mounted on the sensor support, and the guide rod moves up and down with the bottom plate under the action of the reset spring and triggers the sensor; the sensor is connected to the underwater control system through a cable, and transmits the sensing information to the surface monitoring system in real time.

8. The deep-buried submarine cable salvage system according to claim 1, 3 or 4, characterized in that: The jet flushing system includes: a manifold and a jet flushing pump, pipelines and switching valves connected thereto, wherein: the jet flushing pump outlet is connected to the hook cable device, the movable jet flushing mechanism and the cable lifting device through pipelines, and water circuit control valves such as check valves and stop valves are connected in series in the middle of the pipelines.

9. A method for salvaging a deep-buried submarine cable based on the system described in any one of claims 1 to 7, characterized in that: include: Step 1: Position the mother ship above the operation area and lower the underwater salvage platform into the water; Step 2: Plan the cable exploration route. The underwater salvage platform uses thrusters to maneuver underwater, adjusts the longitudinal centerline to coincide with the exploration route, and sits on the bottom; Step 3: Turn on the spray system, lower the cable hook to a 90-degree angle, and let the underwater salvage platform patrol the bottom. Use the cable hook’s induction sensor to detect the cable until both cable hooks detect the cable. Step 4: Lower the movable spraying mechanism and start reciprocating spraying to clean the silt above and on both sides of the cable; Step 5: Gradually lower the cable hoist to the specified depth and close the claws. After confirming that both sets of cable hoist claws have fully grasped the cable, stop closing the claws; Step 6: Retract the mobile jet mechanism to the initial position, and under the gripping state of the cable lifting claw, retract the guide rail drive cylinder step by step and synchronously to lift the cable out of the trench bottom; Step 7: After all the guide rails of the cable hoist are back in place, the two sets of claws continue to close alternately at the same time until the feeler device on the top of the claws senses the position of the cable and the claws are in a fully closed state. At this time, the cable has been unearthed and entered the card position; Step 8: Tie a float or buoy to the cable at the mud discharge section to keep it floating in the water; Step 9: The cable lifting claws are fully opened and the mud section cable is released. The underwater salvage platform moves to the next excavation point and repeats the above steps; Step 10: Use the cable hoist to grab the middle of the excavated cable, and the underwater salvage platform carries the cable as a whole and floats up and recovers it to the deck.

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