Buoyancy-based dynamic equilibrium deployment and recovery method for subsea pipeline mapping fixtures

Abstract

This invention discloses a method for the dynamic buoyancy balance deployment and retrieval of a surveying fixture for subsea pipelines, including a deployment method and a retrieval method. The deployment method involves slowly lowering the surveying fixture into the sea, adjusting buoyancy during deployment by controlling the water inlet of the floating hull and the counterweight; closing the scanning chamber after the pipe is set; draining seawater from the scanning chamber into the floating hull; once the floating hull is full, draining the remaining seawater to the outside; fully lowering the counterweight; and keeping the pneumatic diaphragm pump running. The retrieval method involves inflating the floating hull to allow seawater to flow into the scanning chamber; pressurizing the scanning chamber; opening the scanning chamber; filling it with seawater; slackening the counterweight wire rope; and tensioning the hoisting cable; slowly lifting the fixture while simultaneously pumping air into the floating hull to increase buoyancy, and simultaneously using a hydraulic winch to further loosen the counterweight wire rope, lifting the surveying fixture and counterweight out of the water to complete the retrieval. This invention enables the dynamic buoyancy balance deployment and retrieval of the surveying fixture.

Description

Technical Field

[0001] This invention relates to the field of marine engineering technology, and in particular to a method for the dynamic buoyancy balance deployment and recovery of a tooling system for surveying and mapping subsea pipelines. Background Technology

[0002] Submarine pipelines are pipeline systems laid on the seabed. As a carrier for transporting oil and gas from the ocean to the land, submarine pipelines have been widely used in marine engineering due to their advantages such as continuous transportation, large transport capacity, and convenient management. However, facing the harsh marine environment, they are highly susceptible to chemical corrosion and mechanical damage, and are also affected by external environmental factors such as geological movements and seawater pressure.

[0003] Patent CN115468123A discloses a tooling and method for accurately mapping deformation defects in subsea pipelines, including an outer frame, a scanning chamber, a floating chamber, and counterweights. The scanning chamber is lowered to the seabed and the subsea pipeline is sealed. A 3D scanning drive device inside the scanning chamber drives a 3D scanner to perform a comprehensive scan of the subsea pipeline, achieving accurate mapping of deformation defects. However, the deployment and retrieval processes of this tooling still need improvement. Correct deployment and retrieval are crucial for ensuring its normal operation and require further in-depth research and refinement. Summary of the Invention

[0004] The purpose of this invention is to provide a method for the dynamic buoyancy balance deployment and retrieval of surveying equipment for submarine pipelines, so as to solve the problems existing in the prior art and realize the dynamic buoyancy balance deployment and retrieval of surveying equipment.

[0005] To achieve the above objectives, the present invention provides the following solution:

[0006] This invention provides a method for the dynamic buoyancy balance deployment and recovery of a tooling for surveying submarine pipelines, including a deployment method and a recovery method;

[0007] The deployment method includes the following steps:

[0008] S11: Slowly lower the surveying equipment into the sea, open the exhaust valve and butterfly valve at the same time, and use water pressure to fill the floating hull. At this time, the counterweight wire rope is in a tightened state. The buoyancy during the deployment process is adjusted by the water intake and the counterweight.

[0009] S12: The surveying fixture is fully seated and reaches the predetermined scanning position. After confirming that the seated position is accurate, the scanning chamber is closed and the pipeline to be measured is sealed.

[0010] S13: Switch the three-way valve to connect the scanning chamber and the floating chamber, and use the air inlet to inflate the scanning chamber. At the same time, turn on the submersible pump to drain the seawater in the scanning chamber into the floating chamber. After the floating chamber is full, switch the three-way valve to drain the remaining seawater into the external seawater environment. Then close the three-way valve. At this time, the scanning chamber is full of gas and the floating chamber is full of seawater. Lower the counterweight completely to balance the buoyancy brought by the scanning chamber. The pneumatic diaphragm pump is normally open to maintain the state of the seawater in the scanning chamber being emptied. During the process of draining and inflating, the attitude sensor and winch tension sensor monitor the changes in the status of the surveying tool in real time and adjust it at any time to ensure that the position of the surveying tool does not shift.

[0011] The recycling method includes the following steps:

[0012] S21: Switch the three-way valve to connect the floating pod and the scanning chamber, pump air into the floating pod to allow seawater in the floating pod to flow into the scanning chamber, and then close the three-way valve;

[0013] S22: Pressurize the scanning chamber with air to facilitate opening the scanning chamber. Once the scanning chamber is opened, seawater fills the scanning chamber.

[0014] S23: Operate the hydraulic winch to slack off the counterweight wire rope, while the hoisting cable between the crane and the counterweight is taut.

[0015] S24: The crane hook slowly rises to lift the equipment. During the lifting process, air is continuously pumped into the floating hull to expel the seawater inside and increase buoyancy. At the same time, the hydraulic winch continues to loosen the counterweight wire rope to lift the surveying tooling and counterweight out of the water as a whole, completing the tooling recovery.

[0016] The floating hull and scanning chamber are both installed inside the outer frame. The floating hull is connected to the scanning chamber through a drain pipe. Two ports of the three-way valve are connected to the drain pipe, and the third port of the three-way valve is connected to the outside. The vent valve and butterfly valve are located on the floating hull. The submersible pump is located inside the scanning chamber and is connected to the drain pipe. The counterweight is connected to the hydraulic winch installed on the outer frame through a counterweight wire rope. The attitude sensor is located on the outer frame, and the winch tension sensor is used to detect the tension of the counterweight wire rope.

[0017] The present invention achieves the following technical effects compared to the prior art:

[0018] The buoyancy dynamic balance deployment and recovery method for subsea pipeline mapping fixtures provided by this invention achieves buoyancy dynamic balance deployment and recovery of the mapping fixtures through the combined use of scanning chamber, floating chamber and counterweight. The entire deployment or recovery operation process is simple and reliable, and the method is easy to master. It can be applied to various types of buoyancy adjustment devices and is very easy to promote and apply. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the three-dimensional structure of the tooling used for three-dimensional mapping of submarine pipelines in the embodiment.

[0021] Figure 2 This is a top view of the 3D mapping fixture used for submarine pipelines in the embodiment;

[0022] Figure 3 This is a side view of the 3D mapping fixture used for submarine pipelines in the embodiment.

[0023] In the diagram: 1-Floating hull, 2-Outer frame, 3-Scanning chamber, 4-Drainage pipe, 5-Three-way valve, 6-Floating hull pipe, 7-Butterfly valve, 8-Pneumatic diaphragm pump, 9-Counterweight, 10-Steel cable conduit, 11-Hydraulic winch, 12-Lifting lug, 13-Exhaust valve, 14-Subsea pipeline, 15-Level gauge, 16-Attitude sensor. Detailed Implementation

[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] The purpose of this invention is to provide a method for the dynamic buoyancy balance deployment and retrieval of surveying equipment for submarine pipelines, in order to solve the problems existing in the prior art and achieve dynamic buoyancy balance deployment and retrieval of the surveying equipment.

[0026] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0027] like Figures 1-3As shown, this embodiment provides a tooling for three-dimensional mapping of subsea pipelines, including a floating pod 1, an outer frame 2, and a scanning chamber 3. Both the floating pod 1 and the scanning chamber 3 are installed inside the outer frame 2. The floating pod 1 is connected to the scanning chamber 3 through a drain pipe 4. A three-way valve 5 is provided on the drain pipe 4. Two ports of the three-way valve 5 are connected to the drain pipe 4, and the third port of the three-way valve 5 is connected to the outside. A submersible pump is provided inside the scanning chamber 3 and is connected to the drain pipe 4. The submersible pump is used to pump seawater in the scanning chamber 3 into the floating pod 1 or to the outside through the drain pipe 4. The floating pod 1 is provided with a floating pod pipe 6 that is connected to the outside. A butterfly valve 7 is provided on the floating pod pipe 6. An exhaust valve 13 is also provided on the floating pod 1. A pneumatic diaphragm pump 8 is provided on the outer frame 2 for pumping out seawater from the scanning chamber 3.

[0028] Both the floating tank 1 and the scanning tank 3 are equipped with level gauges 15, which are used to detect the water level in the floating tank 1 and the scanning tank 3, respectively. Both the floating tank 1 and the scanning tank 3 are equipped with air inlets, which are connected to air pumps to regulate the air pressure in the floating tank 1 and the scanning tank 3.

[0029] Each side of the outer frame 2 is equipped with a counterweight 9. The two counterweights 9 are used to suspend the subsea pipeline 14 on both sides. The counterweights 9 are connected to a hydraulic winch 11 mounted on the outer frame 2 via counterweight wire ropes. The hydraulic winch 11 can tighten or loosen the counterweight wire ropes. Both the outer frame 2 and the counterweights 9 are equipped with lifting lugs 12. Cable guide tubes 10 are fixed to both sides of the outer frame 2. The lifting lugs 12 are used to connect lifting cables, and the cable guide tubes 10 are used to thread the lifting cables to connect to the lifting lugs 12 on the counterweights 9. An attitude sensor 16 is installed on the outer frame 2 to monitor the attitude of the 3D mapping fixture on the seabed. A winch tension sensor is installed on the hydraulic winch 11 to detect the tension of the counterweight wire ropes.

[0030] The above-mentioned buoyancy dynamic balance deployment and recovery method for subsea pipeline mapping tooling includes deployment and recovery methods;

[0031] The deployment method includes the following steps:

[0032] S11: Slowly lower the surveying tooling into the sea, open the exhaust valve 13 and the butterfly valve 7 at the same time, and use water pressure to fill the floating pod 1 with water. At this time, the steel wire rope of the counterweight is in a tightened state. The buoyancy during the deployment process is adjusted by the water intake and the counterweight 9.

[0033] S12: The surveying fixture is fully seated and reaches the predetermined scanning position. After confirming that the seated position is accurate, the scanning chamber 3 is closed and the pipeline to be measured is sealed.

[0034] S13: Switch the three-way valve 5 to connect the scanning chamber 3 and the floating chamber 1, and use the air inlet to inflate the scanning chamber 3. At the same time, turn on the submersible pump to drain the seawater in the scanning chamber 3 into the floating chamber 1. After the floating chamber 1 is filled, switch the three-way valve 5 to drain the remaining seawater into the external seawater environment through the three-way valve 5, and then close the three-way valve 5. At this time, the scanning chamber 3 is filled with gas and the floating chamber 1 is filled with seawater. The counterweight 9 is completely lowered to balance the buoyancy brought by the scanning chamber 3. The normally open pneumatic diaphragm pump 8 maintains the state of the seawater in the scanning chamber 3 being emptied. During the process of draining and inflating, the attitude sensor 16 and the winch tension sensor monitor the changes in the status of the surveying tool in real time and adjust it at any time to ensure that the position of the surveying tool does not shift.

[0035] The recycling method includes the following steps:

[0036] S21: Switch the three-way valve 5 to connect the floating pod 1 and the scanning pod 3, pump air into the floating pod 1 to allow the seawater in the floating pod 1 to flow into the scanning pod 3, and then close the three-way valve 5;

[0037] S22: Pressurize the scanning chamber 3 with air to facilitate opening the scanning chamber 3. After opening the scanning chamber 3, seawater fills the scanning chamber 3.

[0038] S23: Operate the hydraulic winch 11 to make the counterweight wire rope slack, while the hoisting cable between the crane and the counterweight 9 is taut.

[0039] S24: The crane hook slowly rises to lift the equipment. During the lifting process, air is continuously pumped into the floating hull 1 to expel the seawater inside and increase buoyancy. At the same time, the hydraulic winch 11 continues to loosen the counterweight wire rope to lift the surveying tooling and counterweight 9 out of the water as a whole, completing the tooling recovery.

[0040] When the surveying tool descends, because float 1 is entirely filled with air, the buoyancy is greater than the weight, which may cause the tool to flip. By introducing water into float 1, the buoyancy is reduced, balancing the buoyancy and weight of the tool, allowing for a smooth descent. After landing, scanning compartment 3 grips the seabed pipeline. Scanning compartment 3 is dewatered, and float 1 is filled with seawater. Scanning compartment 3 is larger than float 1, increasing buoyancy. To overcome this buoyancy, counterweight 9 needs to be fully seated on the ground to balance the buoyancy from scanning compartment 3 and hold the tool body in place. The same principle applies during ascent.

[0041] During the descent, the float 1 needs to be inflated in stages to control the pressure difference between the inside and outside of the float 1 within 0.1 MPa (i.e., the pressure at a water depth of 10 meters), so as to ensure the pressure balance between the inside and outside of the float 1 and the stability during the descent process.

[0042] Using this deployment and retrieval method, the sinking depth of the surveying equipment can be adjusted under high sea conditions. During deployment and retrieval, the wind and wave layers should be avoided, and relatively stable water layers should be selected for deployment and retrieval to improve the efficiency and safety of the deployment and retrieval of the surveying equipment.

[0043] Due to ocean currents and tides, the deployment of surveying equipment must wait until the low tide period.

[0044] After being lowered, the scanning chamber 3 is closed. The full chamber of seawater causes the weight of the entire surveying equipment to be greater than its buoyancy. The weight is balanced by the upper hoisting cable, ensuring the surveying equipment exerts almost no force on the subsea pipeline. To allow the surveying equipment to perform surveying work on the seabed, air is introduced through the air inlet, increasing the air pressure inside the scanning chamber 3 to balance the water pressure outside. Simultaneously, the pneumatic diaphragm pump 8 and the submersible pump inside the scanning chamber 3 are activated to transfer water from the scanning chamber 3 to the floating chamber 1. Since the volume ratio of the floating chamber 1 to the scanning chamber 3 is greater than that of the floating chamber 1, a portion of the water from the scanning chamber 3 is transferred to the floating chamber 1. After the floating chamber 1 is full, the remaining water from the scanning chamber 3 is drained into the external seawater environment. During this internal conversion process, there is no change in the buoyancy of the equipment. Only after the floating chamber 1 is full and the water in the scanning chamber 3 is drained will the buoyancy of the equipment increase, achieving a balance between gravity and buoyancy, and reaching a suspended state.

[0045] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A method of dynamically balancing the buoyancy of a subsea pipeline surveying spread for launch and recovery, characterized by: The application relates to a laying and recovering method for a surveying and mapping device. The laying method comprises the following steps: S11: the surveying and mapping device is slowly hoisted into the sea, the exhaust valve and the butterfly valve are opened, water is filled into the floating cabin by using water pressure, the counterweight steel wire rope is in a tightening state, the buoyancy in the laying process is adjusted by the water volume and the counterweight, S12: the surveying and mapping device is completely lowered, reaches the predetermined scanning position, the sealing cabin is closed and sealed after the position is confirmed, S13: the three-way valve is switched to connect the scanning cabin and the floating cabin, the scanning cabin is inflated by using the inflation port, the seawater in the scanning cabin is discharged into the floating cabin by starting the submersible pump, the remaining seawater is discharged into the external seawater environment by switching the three-way valve after the floating cabin is filled, then the three-way valve is closed, the scanning cabin is filled with gas, the floating cabin is filled with seawater, and the counterweight is completely lowered to balance the buoyancy brought by the scanning cabin; the normally open pneumatic diaphragm pump is started to maintain the seawater emptying state in the scanning cabin; the state change of the surveying and mapping device is monitored in real time and adjusted in time to ensure that the position of the surveying and mapping device does not deviate during the process of discharging water and inflating gas according to the attitude sensor and the winch tension sensor. The recovering method comprises the following steps: S21: the three-way valve is switched to connect the floating cabin and the scanning cabin, the floating cabin is inflated to make the seawater in the floating cabin flow into the scanning cabin, and then the three-way valve is closed, S22: the scanning cabin is inflated and pressurized to facilitate the opening of the scanning cabin, and the scanning cabin is filled with seawater after being opened, S23: the hydraulic winch is operated to make the counterweight steel wire rope in a relaxed state, and the hoisting cable between the crane and the counterweight is in a tension state, S24: the crane hook is slowly lifted for lifting, the internal seawater is discharged to increase the buoyancy by continuously inflating the floating cabin during the lifting process, the counterweight steel wire rope is continuously loosened by the hydraulic winch, the surveying and mapping device and the counterweight are lifted out of the water as a whole, and the device recovering is completed, During the laying and recovering, a relatively stable water layer is selected to avoid the wind and wave layer, The floating cabin and the scanning cabin are installed in the outer frame, the floating cabin is connected with the scanning cabin through the drain pipeline, two ports of the three-way valve are connected with the drain pipeline, the third port of the three-way valve is connected with the external environment, the exhaust valve and the butterfly valve are arranged on the floating cabin, the submersible pump is arranged in the scanning cabin and connected with the drain pipeline, the counterweight is connected with the hydraulic winch arranged on the outer frame through the counterweight steel wire rope, the counterweight steel wire rope can be tightened or loosened by the hydraulic winch, the attitude sensor is arranged on the outer frame, and the winch tension sensor is used for detecting the tension of the counterweight steel wire rope. ​ ​

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