An auxiliary device for the bottom-towing installation of subsea pipelines

Abstract

This application discloses an auxiliary device for the installation of subsea pipelines using the bottom-towing method, belonging to the field of bottom-towing subsea pipeline transportation. This auxiliary device includes a support frame for supporting the subsea pipeline. An inflatable steel pontoon is fixedly installed on the support frame. A buoyancy compensation device for lifting the steel pontoon is installed on the steel pontoon, and the buoyancy compensation device is equipped with FBG strain sensors for attaching to multiple nodes of the subsea pipeline. This auxiliary device for bottom-towing subsea pipeline installation, through the mechanical adjustment of the electric hoist and sling, combined with the real-time feedback from the FBG strain sensors, can accurately compensate for buoyancy in areas of excessive local stress, preventing pipeline damage due to excessive stress. By adjusting the length of the sling, the height of the steel pontoon can be changed to adapt to seabed topographical undulations such as protrusions and depressions, ensuring a uniform pipeline height above the bottom and avoiding localized bottom contact or excessive lifting due to uneven terrain.

Description

Technical Field

[0001] This application relates to the field of submarine pipeline off-bottom towing technology, specifically an auxiliary device for the installation of submarine pipelines using the off-bottom towing method. Background Technology

[0002] The buoyancy-lifting method for laying subsea pipelines is a technique used in marine engineering. Its core principle is to use a support frame and buoyancy modules to lift the pipeline from the seabed and then use towing force to move it to a predetermined location, ultimately completing the laying process. This method is mainly suitable for shallow or medium-depth waters, and is particularly prevalent in areas with relatively flat terrain and few seabed obstacles.

[0003] Although a support frame and buoyancy modules are used, the buoyancy modules usually use foam pontoons with fixed buoyancy or inflatable pontoons that cannot be adjusted during use. Therefore, the local buoyancy is fixed, which can easily lead to local turbulence when encountering seabed obstacles. Especially when the seabed topography is uneven and the height above the bottom cannot be adjusted, it may hit the bottom and cause damage to the pipeline. Therefore, during the towing process, the pipeline may be damaged due to uneven buoyancy distribution of foam pontoons or inflatable pontoons or sudden seabed topography, which may cause local stress to exceed the limit.

[0004] Therefore, this application provides an auxiliary device for the bottom-towing installation of submarine pipelines to solve the above-mentioned problems. Utility Model Content

[0005] This application provides an auxiliary device for the installation of submarine pipelines using the bottom-towing method, which aims to solve the problem mentioned in the background art that existing submarine pipeline bottom-towing auxiliary devices may cause local stress exceeding limits and damage to the pipeline during towing due to uneven buoyancy distribution of foam or inflatable pontoons or sudden seabed topography.

[0006] To achieve the above objectives, this application provides the following technical solution: an auxiliary device for the off-bottom towing installation of a subsea pipeline, comprising a support frame for supporting the subsea pipeline, an inflatable steel buoy fixedly installed on the support frame, a buoyancy compensation device for lifting the steel buoy on the steel buoy, and an FBG strain sensor for attaching to multiple nodes of the subsea pipeline.

[0007] The buoyancy compensation device includes a support, floating pontoons symmetrically welded to both sides of the support, an electric hoist fixedly installed on the support, and a sling with one end connected to the electric hoist reel and the other end connected to the top of the steel pontoons.

[0008] Both the output of the FBG strain sensor and the input of the electric hoist are connected to an external control system. Thus, through the mechanical adjustment of the electric hoist and sling, combined with the real-time feedback from the FBG strain sensor, buoyancy can be precisely compensated for in areas where local stress exceeds limits, preventing pipeline damage due to excessive stress. By adjusting the sling length, the height of the steel pontoon can be changed to adapt to seabed topography such as bumps and depressions, ensuring a uniform pipeline height above the bottom and preventing localized bottom contact or excessive lifting due to uneven terrain.

[0009] Preferably, the FBG strain sensors are all distributed at positions between adjacent support frames on the subsea pipeline.

[0010] Preferably, a lifting lug for connecting the sling is fixedly connected at the center of the top of the steel pontoon.

[0011] Preferably, the FBG strain sensor is connected in series via a single optical fiber.

[0012] Preferably, the support frame includes a connecting seat connected to the bottom of the steel buoy, a locking groove fixedly disposed on the connecting seat, a strap fixedly connected at one end to the connecting seat and passing through the locking groove at the other end for binding the subsea pipeline, and an electric lock fixedly installed on the locking groove for locking the strap, wherein the input end of the electric lock is connected to an external control system.

[0013] Preferably, both ends of the connecting seat are fixedly connected to a traction head, and two adjacent connecting seats are connected by a drag wire rope through the traction head. The drag wire rope corresponding to the beginning of the pipeline is connected to an external dragging device.

[0014] Preferably, the connecting seat is fixedly installed with the steel pontoon by bolts and nuts.

[0015] This auxiliary device for the off-bottom towing installation of subsea pipelines, through the mechanical adjustment of electric hoists and slings, combined with real-time feedback from FBG strain sensors, can accurately compensate for buoyancy in areas where local stress exceeds limits, thus preventing pipeline damage due to excessive stress.

[0016] This auxiliary device for the off-bottom towing installation of submarine pipelines can adjust the height of the steel buoy by adjusting the length of the sling, adapting to the undulations of the seabed such as protrusions and depressions, ensuring that the pipeline is at a uniform height from the bottom, and avoiding local contact with the bottom or excessive lifting due to uneven terrain. Attached Figure Description

[0017] Figure 1 A schematic diagram of an auxiliary device for the bottom-towing installation of subsea pipelines;

[0018] Figure 2 for Figure 1Enlarged structural diagram at point A;

[0019] Figure 3 for Figure 1 Enlarged structural diagram at point B.

[0020] In the picture:

[0021] 1. Submarine pipelines;

[0022] 2. Support frame; 21. Connector; 22. Lock slot; 23. Straps; 24. Electric lock; 25. Towing head;

[0023] 3. Steel pontoon; 31. Lifting lug; 4. Buoyancy compensation device; 41. Support; 42. Floating pontoon; 43. Electric hoist; 44. Lifting sling;

[0024] 5. Drag steel wire rope; 6. FBG strain sensor. Detailed Implementation

[0025] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0026] This embodiment provides an auxiliary device for the off-bottom towing method of installing subsea pipelines, such as... Figures 1-3 As shown, the auxiliary device for the bottom-towing installation of the subsea pipeline includes a support frame 2 for supporting the subsea pipeline 1. An inflatable steel pontoon 3 is fixedly installed on the support frame 2. A buoyancy compensation device 4 for lifting the steel pontoon 3 is provided on the steel pontoon 3. The buoyancy compensation device 4 is equipped with FBG strain sensors 6 for attaching to multiple nodes of the subsea pipeline 1.

[0027] The buoyancy compensation device 4 includes a support 41, floating pontoons 42 symmetrically welded on both sides of the support 41, an electric hoist 43 fixedly installed on the support 41, and a sling 44 with one end connected to the reel of the electric hoist 43 and the other end connected to the top of the steel pontoon 3.

[0028] The output of the FBG strain sensor 6 and the input of the electric hoist 43 are both connected to an external control system.

[0029] In operation, the support frame 2 is fixedly installed on the subsea pipeline 1. The pipeline is lifted off the seabed by the basic buoyancy of the inflated steel pontoon 3, ensuring that the buoyancy of the steel pontoon 3 is less than the weight of the corresponding pipeline section, thus ensuring the pipeline sinks. Then, the surface pontoon 42 provides additional buoyancy, working together with the steel pontoon 3 to maintain the pipeline above the seabed. FBG strain sensors 6 are attached to key nodes of the pipeline and connected to the external control system. During operation, the tugboat begins to move the pipeline. The FBG strain sensors 6 collect strain data at each node in real time and transmit it to the control system. The control system processes the data. If the strain at a certain node exceeds a preset threshold, it is determined that there is a risk of local stress exceeding the limit in that area. The control system identifies the corresponding buoyancy compensation device 4 based on the location of the stress exceeding the limit and adjusts the length of the sling 44 by activating the corresponding electric hoist 43 to change the height of the corresponding pipeline section and avoid touching the bottom. During towing, the control system continuously receives FBG strain data and dynamically adjusts the sling length of each buoyancy compensation device 4 to ensure that the stress at each node of the pipeline is always below the safety threshold.

[0030] Specifically, the FBG strain sensors 6 are all distributed at the locations between the adjacent support frames 2 of the subsea pipeline 1. The FBG strain sensors 6 are connected in series via a single optical fiber. The pipeline section between the adjacent support frames 2 is the area with the most complex stress during towing. It is prone to bending stress due to uneven buoyancy or terrain undulations. Placing the sensors here can accurately monitor the strain of key nodes in the pipeline. Through wavelength division multiplexing technology, multiple FBG sensors are connected in series on a single optical fiber to achieve distributed monitoring. The external control system receives the reflected light signals through a demodulator and analyzes the strain data of each sensor.

[0031] Specifically, a lifting lug 31 for connecting the sling 44 is fixedly connected at the center of the top of the steel pontoon 3; the lifting lug 31 is located at the center of the top of the pontoon to ensure that the tension applied by the sling 44 is perpendicular to the axis of the pontoon, so as to avoid the pontoon tilting or deforming due to eccentric load.

[0032] Furthermore, the support frame 2 includes a connecting base 21 connected to the bottom of the steel pontoon 3, a locking groove 22 fixedly mounted on the connecting base 21, a strap 23 fixedly connected at one end to the connecting base 21 and passing through the locking groove 22 for securing the subsea pipeline 1, and an electrically controlled lock 24 fixedly mounted on the locking groove 22 for locking the strap 23. The input end of the electrically controlled lock 24 is connected to an external control system. After the strap 23 wraps around the pipeline, it passes through the locking groove 22. The electrically controlled lock 24, driven by a motor, inserts the locking tongue into the locking hole of the strap 23 to achieve quick fixation. The control system can send commands to unlock, facilitating pipeline installation or adjustment. It can adapt to pipelines of different diameters and can automatically unlock after the pipeline is transported to its destination, eliminating the hassle of manual disassembly.

[0033] It should be noted that both ends of the connecting seat 21 are fixedly connected to the traction head 25. Adjacent connecting seats 21 are connected by the traction head 25 and the drag wire rope 5. The drag wire rope 5 at the corresponding pipe end is connected to the external dragging device. The drag wire rope 5 is connected in series with multiple support frames 2 to form a flexible traction chain. The dragging force is evenly transmitted to each support frame 2 through the wire rope 5 to avoid local stress concentration. The distributed traction makes the force on each section of the pipe more balanced. The bending radius of the pipe can be controlled during the towing process to avoid excessive bending that leads to material fatigue.

[0034] Specifically, the connecting seat 21 is fixedly installed with bolts and nuts and steel pontoons 3; the bolt connection allows for quick disassembly and assembly of pontoons 3 and support frame 2, facilitating maintenance and replacement.

[0035] The above description is merely a preferred embodiment of this application, but the scope of protection of this application is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in this application, based on the technical solution and concept of this application, should be included within the scope of protection of this application.

Claims

1. An auxiliary device for subsea pipeline off-bottom tow installation comprising a pipe support rack (2) for supporting a subsea pipeline (1), characterised in that: An inflatable steel pontoon (3) is fixedly installed on the support frame (2). A buoyancy compensation device (4) for lifting the steel pontoon (3) is provided on the steel pontoon (3). The buoyancy compensation device (4) is equipped with FBG strain sensors (6) for attaching to multiple nodes of the submarine pipeline (1). The buoyancy compensation device (4) includes a support (41), floating pontoons (42) symmetrically welded on both sides of the support (41), an electric hoist (43) fixedly installed on the support (41), and a sling (44) with one end connected to the reel of the electric hoist (43) and the other end connected to the top of the steel pontoon (3). The output end of the FBG strain sensor (6) and the input end of the electric hoist (43) are both connected to an external control system.

2. An auxiliary device for installation of a subsea pipeline by the method of bottom pull-off towing according to claim 1, characterized in that: The FBG strain sensors (6) are all distributed at positions between adjacent support frames (2) on the subsea pipeline (1).

3. An auxiliary device for installation of a subsea pipeline by the method of bottom pull-off towing according to claim 2, characterized in that: The steel pontoon (3) is fixedly connected to a lug (31) for connecting the sling (44) at the center of the top.

4. The auxiliary device for the off-bottom towing installation of subsea pipelines according to claim 3, characterized in that: The FBG strain sensor (6) is connected in series via a single optical fiber.

5. An auxiliary device for installation of a subsea pipeline by the method of bottom pull-off towing according to claim 4, characterized in that: The support frame (2) includes a connecting seat (21) connected to the bottom of the steel buoy (3), a locking groove (22) fixedly installed on the connecting seat (21), a strap (23) with one end fixedly connected to the connecting seat (21) and the other end passing through the locking groove (22) for binding the subsea pipeline (1), and an electric lock (24) fixedly installed on the locking groove (22) for locking the strap (23). The input end of the electric lock (24) is connected to an external control system.

6. An auxiliary device for installation of a subsea pipeline by the method of bottom pull-off towing according to claim 5, characterized in that: Both ends of the connecting seat (21) are fixedly connected to a traction head (25). Two adjacent connecting seats (21) are connected by a drag wire rope (5) through the traction head (25). The drag wire rope (5) at the corresponding pipe end is connected to an external dragging device.

7. An auxiliary device for installation of a subsea pipeline by the method of bottom pull-off towing according to claim 6, characterized in that: The connecting seat (21) is fixedly installed by bolts and nuts and the steel pontoon (3).

Images