Submarine pipeline reinforcing system

Abstract

The invention discloses a submarine pipeline reinforcing system which comprises a grouting system and a plurality of anchoring structures, and the anchoring structures are detachably installed on a submarine pipeline (1) at intervals. The grouting system comprises a grouting hose (4), a grouting pipeline (2) and a grouting channel (31) formed in the anchoring structure. The grouting pipelines (2) are installed on the two sides of the lower portion of the submarine pipeline (1), and a plurality of guniting holes (35) are formed in the grouting pipelines (2) at intervals. One end of the grouting channel (31) is communicated with the grouting pipeline (2), and the other end of the grouting channel (31) leads to a guniting port (32) positioned at the bottom of the anchoring structure and at the lower part of one side, far away from the submarine pipeline, of the anchoring structure; and grouting is conducted on the grouting pipeline (2) through the grouting hose (4), and grout is sprayed out from the grout spraying holes (35) and the grout spraying openings (32). The bottom of the anchor plate and the two sides of the submarine pipeline are grouted, gaps of the pipeline seabed are filled, the soil bearing capacity is improved, linear protection is achieved, and the method adapts to safe laying of complex seabed pipelines.

Description

Technical Field

[0001] This invention relates to the field of subsea pipeline reinforcement, and in particular to a subsea pipeline reinforcement system. Background Technology

[0002] Submarine pipelines serve as transoceanic transportation channels for resources such as oil and gas, playing a vital role in the country's long-distance energy transmission and economic development. Submarine pipelines typically undergo a series of protective measures, including concrete weighting and corrosion protection, before sinking to the seabed under their own weight. They are either laid on the seabed surface or buried at a certain depth within the marine soil through excavated trenches, thus ensuring the safe transportation of oil and gas.

[0003] However, the marine environment is complex, especially the long-term effects of wind, waves, and ocean currents, which cause continuous erosion of the surrounding marine soil. This exposes the original trenches of pipelines laid on the seabed or buried in the marine soil, resulting in the pipelines being suspended in mid-air. When the suspension reaches a certain extent, the pipeline loses its effective support and is damaged by large bending moments and forces. At the same time, vortex-induced vibrations caused by hydrodynamic loads lead to fatigue failure, resulting in pipeline fractures and oil and gas leaks. Therefore, developing new, efficient, and economical anti-erosion technologies for subsea pipelines has significant engineering application value.

[0004] Chinese patent application CN109610462A discloses a grouting protection method and grouting equipment for submarine pipeline scour disasters. By setting up a grouting device, targeted grouting is performed at key points of the pipeline to enhance local support and mitigate the suspension and deformation of the submarine pipeline caused by scour, demonstrating some engineering applicability. However, its reinforcement mode, primarily point-based, lacks continuity along the pipeline and is ill-suited for long-distance scour or multi-segment suspension scenarios. Furthermore, the device requires underwater installation, making the construction process complex and reliant on diving operations or underwater machinery, resulting in low efficiency and high costs. Additionally, the grout may solidify and encapsulate a large area between the device and the soil during grouting, causing the entire device to become integrated with the surrounding structure. Once solidified, it becomes difficult to remove or pull out, severely impacting the feasibility of subsequent reinforcement operations. Moreover, the grouting device lacks a lateral anchoring structure, failing to constrain the pipeline's movement or displacement, and its widespread application in complex marine environments still faces numerous challenges. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention provides a submarine pipeline reinforcement system that features good stability, high construction efficiency, and convenient maintenance.

[0006] Therefore, the present invention adopts the following technical solution:

[0007] A subsea pipeline reinforcement system includes a grouting system and anchoring structures. Multiple anchoring structures are spaced apart and detachably installed on the subsea pipeline. The grouting system includes grouting hoses, grouting pipes, and grouting channels formed within each anchoring structure. The grouting pipes are installed on both sides of the lower portion of the subsea pipeline, and multiple grouting holes 35 are formed at intervals on the grouting pipes. One end of each grouting channel communicates with the grouting pipe, and the other end connects to a grouting port located at the bottom of the anchoring structure and on the lower part of the anchoring structure away from the subsea pipeline. Grout is injected into the grouting pipes through the grouting hoses, and the grout is ejected from the grouting holes and grouting ports, filling the seabed on both sides of the subsea pipeline and around the anchoring structures, ultimately forming a composite reinforced body.

[0008] In one embodiment of the present invention, the anchoring structure is formed by two anchor plates that are detachably and fixedly connected. Each of the two anchor plates has a slot formed on the upper part of an adjacent side, and the two slots together form an opening that can be fitted onto the subsea pipeline. The two anchor plates are fixedly connected to the subsea pipeline by clamps. The grouting channel is formed in each anchor plate.

[0009] Preferably, the portion of the grouting channel connected to the grouting nozzle on the side furthest from the subsea pipeline is inclined, with an angle of 30° to 45° with the horizontal direction.

[0010] Preferably, there are two grouting pipes, which are welded to both sides of a base plate, and the base plate is welded to the bottom of the subsea pipeline; multiple grouting holes are spaced apart on the lower outer side of each grouting pipe so that the sprayed grout covers the soil area on both sides of the pipe.

[0011] Preferably, the port where the grouting channel communicates with the grouting pipe is located at the edge of the slot and is fixedly connected to the connection port on the grouting pipe.

[0012] Preferably, a rubber strip or elastic pad is provided at the contact surface between the slot and the subsea pipeline. A one-way check valve to prevent seawater and sediment backflow is installed in the grouting channel near the grouting nozzle. A flexible membrane is also installed at the grouting nozzle, which opens and closes with the one-way check valve.

[0013] Compared with the prior art, the present invention has the following beneficial effects:

[0014] 1. Integrated structural design enhances construction efficiency and stability: This invention integrates the "anchoring structure" and "grouting system" into a single module, which can be pre-installed and pre-assembled on land or ship platforms, and is simultaneously lowered along with the pipeline during the pipeline lowering process. Compared to the traditional multi-step construction method of "laying the pipeline first, installing the anchor plate later, and performing grouting separately," this greatly reduces complex operations such as underwater assembly, alignment, and connection, significantly improving project efficiency and installation accuracy, and reducing construction risks and operational window requirements.

[0015] 2. The reinforcement method of the present invention, after positioning is completed, continuously injects grout into the bottom and sides of the anchor plate through a grouting system to form a reinforcement cushion layer distributed along the entire pipeline. This grouting reinforcement cushion layer not only effectively fills the gaps that may exist between the pipeline and the seabed, preventing suspension, vibration and structural fatigue caused by local scour, but also improves the bearing capacity and shear strength of the local soil, thereby achieving active, linear, stable and reliable scour protection.

[0016] 3. Compared with existing methods of "point support" or "discrete covering", the method of the present invention has the advantages of strong continuity, fast response, and adaptability to varying terrain and water depth conditions. It can be widely applied to the safe laying and long-term service of soft foundations, scour sections, uneven settlement areas, heat-sensitive areas, complex seabeds and long-distance deep-water pipelines.

[0017] 4. Built-in nozzles + check valve structure to ensure grouting direction control and pipeline safety: In this invention, the grouting nozzles on the anchor plate are all integrated with a one-way check valve structure. The design of spring and flexible diaphragm can open under grouting pressure and close automatically after grouting is completed. This effectively prevents seawater, silt, and suspended particles from flowing back into the grouting cavity or blocking the channel, avoiding system failure and improving long-term stability and repeatable grouting capability. The grout consolidation area can be coupled with the soil for a long time and is not easily damaged, avoiding later structural loosening or functional failure. Attached Figure Description

[0018] Figure 1 This is a partial structural diagram of the reinforcement system in an embodiment of the present invention.

[0019] Figure 2 for Figure 1 A three-dimensional structural diagram of an anchoring structure;

[0020] Figure 3 for Figure 1 Front view of the intermediate anchorage structure;

[0021] Figure 4 This is a schematic diagram of the structure at the spray nozzle in an embodiment of the present invention.

[0022] In the picture:

[0023] 1. Submarine pipeline; 2. Grouting pipeline; 3. Anchor plate; 4. Grouting hose; 21. Connection port; 22. Gasket; 31. Grouting channel; 32. Grouting nozzle; 33. Slot; 34. Bolt; 35. Grouting hole; 36. Clamp; 321. Valve plate; 322. Spring; 323. Flexible membrane. Detailed Implementation

[0024] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings and embodiments. Obviously, the following 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] Example 1

[0026] See Figures 1-3 The present invention provides a subsea pipeline reinforcement system, comprising: a grouting system and a plurality of spaced-apart anchoring structures, wherein:

[0027] The anchoring structure includes two fixedly connected anchor plates 3. Each anchor plate 3 has a groove 33 formed on its upper inner side, and the two grooves 33 together form an opening. The anchoring structure is fitted onto the subsea pipeline 1 through the opening and is fixedly connected to the subsea pipeline 1 by a clamp 36. Multiple anchoring structures are arranged on the subsea pipeline at certain intervals. The bolt 34, the two grooves 33, and the clamp 36 form a detachable locking mechanism. The anchor plates 3 can be pre-installed on the subsea pipeline 1 and lowered to the target position on the seabed along with the subsea pipeline 1. Preferably, a rubber strip or elastic pad is provided at the contact surface between the groove 33 and the subsea pipeline 1 to prevent damage to the outer wall of the subsea pipeline 1 during clamping and to improve the stability of the clamping. To facilitate the insertion of the anchor plates into the seabed, the bottom cross-section of the anchor plate 3 can be wedge-shaped, or the bottom of the anchor plate 3 can be made into an inverted trapezoid (i.e., a smaller bottom base). Additionally, depending on the different soil conditions at the seabed, a hydraulic impact device can be selected to assist in the insertion of the anchor plates 3.

[0028] The grouting system consists of grouting hoses 4, grouting pipes 2, and grouting channels 31 formed within each anchoring structure. In this embodiment, there are two grouting pipes 2, which are fixed (e.g., welded or otherwise suitable) to both sides of a high-strength, corrosion-resistant pad 22, which is welded to the bottom of the subsea pipeline 1. Multiple grouting holes 35 are spaced apart on the lower outer side of each grouting pipe 2 to cover the soil area on both sides of the pipe with the sprayed grout. The grouting pipe 2 is connected to the anchor plate's grouting channel 31 via a connection port 21 on the grouting pipe 2.

[0029] The grouting channel 31 has two branches at its end, which lead to the bottom of the anchor plate 3 and the grouting port 32 on the lower outer side, respectively. The branch leading to the lower outer side of the anchor plate 3 has an angle of 30° to 45° with the horizontal direction.

[0030] like Figure 4 As shown, a one-way check valve to prevent backflow of seawater and sediment is also installed at the end of the grouting nozzle 32. The one-way check valve includes a valve plate 321 and a spring 322 (stainless steel compression spring). The upper end of the valve plate 321 is hinged to the inner wall of the grouting channel 31. The spring 322 is installed between the valve plate 321 and the grouting nozzle 32, with its upper end connected to the inner wall of the grouting channel 31 and its other end connected to the valve plate 321. Additionally, a flexible membrane 323 is installed at the grouting nozzle 32. The upper end of the flexible membrane 323 is connected to the grouting nozzle 32, and its lower end is connected to the lower end of the valve plate 321. The flexible membrane 323 opens and closes with the one-way check valve, ensuring a tight seal when the valve plate is closed.

[0031] During grouting, the grout opens the valve plate 321, causing the flexible membrane 323 to open the grout nozzle 32, allowing the grout to spray out. After grouting is completed, the valve plate 321 closes under the action of the compression spring 322, causing the flexible membrane 323 to return to its original position.

[0032] Since the grouting holes 35 spray to both sides, although there is solidified grout at the bottom, there is no clear supporting structure. Therefore, adding a bottom pad can form a clearer "rigid support", indirectly coupling the soil formed by grouting with the grouting pipe 2, which helps to evenly distribute the pipe's self-weight and hydrodynamic load.

[0033] The process of reinforcing a subsea pipeline using the aforementioned subsea pipeline reinforcement system is as follows:

[0034] See Figure 1 On the construction platform, the lower part of the subsea oil and gas pipeline 1 is welded and fixed to the grouting pipeline 2 and the steel plate cushion layer 22. One end of the grouting pipeline 2 is fixedly connected to one end of the grouting hose 4, and the other end of the grouting hose 4 is equipped with a grouting joint to facilitate subsequent grouting. The connection method can adopt a standardized quick-plug interface. Multiple anchoring structures are installed on the subsea pipeline 1 at certain intervals. After pre-installation, the reinforcement system and pipeline are lowered to the seabed as a whole, and the bottom of the anchor plate 3 is inserted into the seabed. After the lowering is completed, the mother ship connects the grouting hose to the grouting pump system through a robotic arm or a diver to start grouting. The grout enters the grouting pipeline 2 through the grouting hose. Part of the grout is sprayed out from the grouting hole 35 on the grouting pipeline 2 to fill the soil on both sides and the bottom of the subsea pipeline 1. The other part of the grout enters the grouting channel 31 on the anchor plate 3 and flows to the grouting nozzle 32 to fill the soil around the anchor plate 3, forming a bearing cushion layer. After the sprayed grout solidifies, it forms a composite reinforced body, which together with the anchor plate and pad plate forms an integrated stable structure of "clamping + grouting + bottom support", thus completing the bottom support and anchoring reinforcement of the subsea pipeline.

[0035] Anchor plate 3 can also be fixed to the pre-set points on the pipeline by welding.

[0036] Example 2

[0037] In this embodiment, the anchoring structure is made of high-strength corrosion-resistant stainless steel or marine steel plate, and is nearly rectangular in shape. The thickness of the anchoring structure is 20mm, the height is 800mm, and the width is 400-600mm. The interval between adjacent anchoring structures is 10-15m.

[0038] In this embodiment, the diameters of the spray hole 35 and the grouting channel 31 are both 16 mm.

[0039] In this embodiment, the valve plate 321 is made of stainless steel; the number of branches of the grouting channel 31 can be adjusted according to project requirements, and generally two branches are set.

Claims

1. A subsea pipeline reinforcement system, characterized in that: The system includes a grouting system and anchoring structures, wherein multiple anchoring structures are provided and are detachably installed on the subsea pipeline (1) at intervals; the grouting system includes grouting hoses (4), grouting pipes (2), and grouting channels (31) formed within each anchoring structure, wherein: The grouting pipe (2) is installed on both sides of the lower part of the submarine pipe (1), and a plurality of grouting holes (35) are formed at intervals on the grouting pipe (2); One end of the grouting channel (31) is connected to the grouting pipe (2), and the other end is connected to the grouting port (32) located at the bottom of the anchoring structure and at the lower part of the anchoring structure away from the seabed pipe. Grout is injected into the grouting pipe (2) through the grouting hose (4). The grout is sprayed out from the grouting hole (35) and the grouting nozzle (32) respectively, filling the seabed on both sides of the subsea pipe and around the anchoring structure, and finally forming a composite reinforced body.

2. The subsea pipeline reinforcement system according to claim 1, characterized in that: The anchoring structure is formed by two anchor plates (3) that are detachably fixedly connected. Each of the two anchor plates (3) has a slot (33) formed on the upper part of an adjacent side. The two slots (33) together form an opening that can be fitted onto the subsea pipeline (1). The two anchor plates (3) are fixedly connected to the subsea pipeline (1) by clamps (36). The grouting channel (31) is formed in each anchor plate (3).

3. The subsea pipeline reinforcement system according to claim 2, characterized in that: The grouting channel (31) is inclined at the part of the grouting port on the side away from the submarine pipeline, with an angle of 30° to 45° with the horizontal direction.

4. The subsea pipeline reinforcement system according to claim 2, characterized in that: There are two grouting pipes (2), which are welded to both sides of the pad (22), and the pad (22) is welded to the bottom of the subsea pipeline (1); multiple grouting holes (35) are spaced apart on the lower outer side of each grouting pipe (2) so that the sprayed grout covers the soil area on both sides of the pipe.

5. The subsea pipeline reinforcement system according to claim 4, characterized in that: The port of the grouting channel (31) that communicates with the grouting pipe (2) is located at the edge of the slot (33) and is fixedly connected to the connection port (21) on the grouting pipe (2).

6. The subsea pipeline reinforcement system according to claim 2, characterized in that: A rubber strip or elastic pad is provided at the contact surface between the slot (33) and the submarine pipeline (1).

7. The subsea pipeline reinforcement system according to claim 1, characterized in that: A one-way check valve is installed in the grouting channel (31) near the grouting port (32) to prevent seawater and silt from flowing back in.

8. The subsea pipeline reinforcement system according to claim 7, characterized in that: A flexible membrane (323) is also installed at the spray nozzle (32), which opens and closes with the one-way check valve.

9. The subsea pipeline reinforcement system according to any one of claims 2-8, characterized in that: The bottom of the anchor plate (3) is wedge-shaped.

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