Boat-plough integrated coupling subsea pipeline ditching protection method

Abstract

The invention discloses a boat-plough integrated coupling subsea pipeline ditching protection method which mainly comprises the following steps that a ditching plough is lowered from a construction ship, the ditching plough falls to the position over a subsea pipeline, and pipe holding and pipe supporting are prepared; after the furrow plough completes pipe holding and pipe supporting, the plough shoe descends; the plough share is closed, the ditching plough starts to make a slope, and ditching is started; the ditching depth of the ditching plough is adjusted, and ditching operation is started along the route; the ditching operation is completed, the ditching machine is lifted, and the umbilical cable and the towing cable are recycled, so that the ditching plough is recycled to the deck. The boat-plough integrated coupling subsea pipeline trenching protection method provided by the invention has relatively high dredging capacity and trenching precision, and a large amount of subsea trenching operation can be completed within a short time, so that the construction efficiency is improved. According to the method, the neat V-shaped gullies can be dug, the shear strength of adjacent soil is not reduced, the gullies are accurate, and the precision requirements of laying of various subsea pipelines can be met.

Description

Technical Field

[0001] This invention belongs to the field of underwater trenching technology, and particularly relates to a method for protecting subsea pipeline trenching by integrating a ship and plow. Background Technology

[0002] There is a large demand for pipeline burial in the offshore oil sector, and the main trenching method currently used is jet trenching to achieve the purpose of laying subsea pipelines.

[0003] Traditional jet dredging methods cannot be used for dredging thicker subsea pipelines. The efficiency of jet dredging is largely limited by pump pressure. If the pump pressure is insufficient, the soil breaking effect may be unsatisfactory, which in turn affects the progress and quality of dredging.

[0004] In addition, the nozzle is a key component in jet dredging, and its lifespan is relatively short. Secondly, jet dredging has certain requirements regarding geological conditions. For example, in complex geological conditions such as gravel and mud, the nozzle's soil-breaking efficiency may be affected, and it may even lead to nozzle damage.

[0005] Therefore, there is an urgent need to design a method for protecting subsea pipelines by integrating ship and plow, in order to solve the problems mentioned above. Summary of the Invention

[0006] To address the technical problems mentioned in the background art regarding traditional trenching methods, such as limited pump pressure, limited nozzle life, soil clogging, geological conditions, complex construction equipment, and high construction costs, a method for integrated ship-plow coupling for submarine pipeline trenching protection is provided to solve the problem of trenching protection operations for submarine pipelines.

[0007] To achieve the above objectives, the specific technical solution of the ship-plow integrated coupling method for protecting subsea pipeline trenching of the present invention is as follows: A method for protecting subsea pipelines by integrating ship and plow coupling mainly includes the following steps: S1. The trenching plow is lowered from the construction vessel and placed directly above the subsea pipeline, ready for the pipeline to be held and managed. S2. After the trenching plow has completed the pipe clamping and support, lower the plow boot; S3. Close the plowshare, and the trenching plow begins to create a slope and start digging the initial trench; S4. Adjust the trenching depth of the trenching plow and start trenching operation along the route; S5. Complete the trenching operation, lift the trenching machine, and retrieve the umbilical cable and tow cable to bring the trenching plow back to the deck.

[0008] Furthermore, in S1, when the trenching plow is lowered, the trenching plow is connected to the tow cable and the umbilical cable.

[0009] Furthermore, multiple buoys are connected at intervals to the umbilical cable so that the umbilical cable floats on the sea surface.

[0010] Furthermore, in S1, the construction vessel continuously lowers the trenching plow until it lands directly above the subsea pipeline.

[0011] Furthermore, the subsea pipeline is located on the seabed and is distributed in a straight line.

[0012] Furthermore, in S4, the construction vessel, towing a tow cable, begins to pull the trenching plow, gradually lowering the plow boot height to reach the trenching depth, so as to begin trenching operations along the route.

[0013] Furthermore, in S4, the mudguards of the trenching plow are adjusted to enable simultaneous trenching and backfilling.

[0014] Furthermore, in S4, when the ditching plow is about to reach the ditch exit point, the ditching plow raises its plow boot to allow the ditching plow to complete the exit.

[0015] Further, in S5, the pipeline is re-secured, the support frame is opened, the subsea pipeline is placed on the seabed, the pipe gripper is activated, and the trenching operation is completed.

[0016] Furthermore, in S2, before the trenching plow performs the pipe-holding operation, it must be positioned directly above the subsea pipeline, and the positioning accuracy of the front and rear rollers of the trenching plow must be less than or equal to 0.5 meters.

[0017] The integrated ship-plow coupling method for protecting subsea pipeline trenches in this invention has the following advantages: It possesses strong dredging capabilities and trenching precision, enabling the completion of a large number of subsea trenching operations in a short time, thereby improving construction efficiency. This application can excavate neat V-shaped trenches without reducing the shear strength of the adjacent soil, and the trench shape is precise, meeting the accuracy requirements of various subsea pipeline laying. Attached Figure Description

[0018] Figure 1 This is a flowchart of the method for protecting subsea pipelines by integrating ship and plow coupling according to the present invention. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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, 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.

[0020] Those skilled in the art will understand that although some embodiments herein include certain features included in other embodiments but not others, combinations of features from different embodiments are intended to be within the scope of the invention and form different embodiments. For example, in the claims, any of the claimed embodiments can be used in any combination.

[0021] The following is a reference to the appendix. Figure 1 This invention describes a method for protecting subsea pipelines by integrating a ship and plow.

[0022] like Figure 1 As shown, the integrated ship-plow coupling method for protecting subsea pipelines during trenching in this invention mainly includes the following steps: S1. The trenching plow is lowered from the construction vessel and placed directly above the subsea pipeline, ready for the pipeline to be held and managed. S2. After the trenching plow has completed the pipe clamping and support, lower the plow boot; S3. Close the plowshare, and the trenching plow begins to create a slope and start digging the initial trench; S4. Adjust the trenching depth of the trenching plow and start trenching operation along the route; S5. Complete the trenching operation, lift the trenching machine, and retrieve the umbilical cable and tow cable to bring the trenching plow back to the deck.

[0023] After coupling the trenching plow equipment with the marine engineering vessel, trenching protection operations are carried out on the submarine pipeline. The entire set of plow-type trenching equipment is optimized according to the deck of the engineering vessel, and the equipment is powered by the ship's electrical system. At the same time, the trenching plow command center is transmitted to the ship's bridge via network cable, making the bridge the control center of the entire construction.

[0024] As a preferred embodiment, the technical construction can be divided into three construction phases: construction mobilization and preparation, on-site trenching operation, and project equipment decommissioning, which includes six work items: ship adaptation modification, mobilization and commissioning of trenching equipment on the ship, initial trenching operation, crossing at intersections, reverse trenching operation, and decommissioning of trenching equipment.

[0025] In S1, when the trenching plow is lowered, a towing cable and an umbilical cable are connected to the trenching plow, and multiple buoys are connected to the umbilical cable at intervals so that the umbilical cable floats on the sea surface; the umbilical cable provides power to the trenching plow and controls the trenching plow to dig trenches.

[0026] Furthermore, in S1, the construction vessel continuously lowers the trenching plow until it lands directly above the subsea pipeline, which is pre-attached to the seabed and is distributed in a straight line.

[0027] In S2, before the trenching plow performs pipe-holding operations, it must be positioned directly above the subsea pipeline, and the positioning accuracy of the front and rear rollers of the trenching plow must be less than or equal to 0.5 meters.

[0028] In S4, the construction vessel tows the tow cable to start pulling the trenching plow, gradually lowering the height of the plow boot to reach the preset trenching depth, so as to start trenching operations along the route; specifically, by adjusting the mudguard of the trenching plow, it is possible to dig trenches and fill them at the same time.

[0029] Preferably, when the ditching plow is about to reach the ditch exit point, the ditching plow controls the plow shoe to rise so that the ditching plow completes the exit.

[0030] In S5, the trenching plow re-grabs the pipe, the support frame is opened, the subsea pipe is placed on the seabed, the pipe gripper is activated, and the trenching operation is completed.

[0031] The method for protecting subsea pipelines by integrating ship and plow has strong dredging capabilities and trenching accuracy, enabling the completion of a large number of subsea trenching operations in a short time, thereby improving construction efficiency. This application can excavate neat V-shaped trenches without reducing the shear strength of the adjacent soil, and the trench shape is precise, meeting the accuracy requirements of various subsea pipeline laying.

[0032] It is suitable for various seabed environments, including different water depths and soil types, and has wide applicability. In summary, the integrated ship-plowing coupling method for post-dredging of subsea pipelines has advantages such as high operational efficiency, precise trench design, strong adaptability, good protection effect, good economy, and simple operation.

[0033] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method for protecting subsea pipelines through integrated ship-plow coupling, characterized in that, The main steps include: S1. The trenching plow is lowered from the construction vessel and placed directly above the subsea pipeline, ready for the pipeline to be held and managed. S2. After the trenching plow has completed the pipe clamping and support, lower the plow boot; S3. Close the plowshare, and the trenching plow begins to create a slope and start digging the initial trench; S4. Adjust the trenching depth of the trenching plow and start trenching operation along the route; S5. Complete the trenching operation, lift the trenching machine, and retrieve the umbilical cable and tow cable to bring the trenching plow back to the deck.

2. The method for protecting subsea pipelines by integrating ship and plow coupling as described in claim 1, characterized in that, In S1, when the trenching plow is lowered, the trenching plow is connected to the tow cable and the umbilical cable.

3. The method for protecting subsea pipelines by integrating ship and plow coupling according to claim 2, characterized in that, Multiple buoys are connected at intervals to the umbilical cable so that the umbilical cable floats on the sea surface.

4. The method for protecting subsea pipelines by integrating ship and plow coupling according to claim 1, characterized in that, In S1, the construction vessel continuously lowers the trenching plow until it lands directly above the subsea pipeline.

5. The method for protecting subsea pipelines by integrating ship and plow coupling according to claim 4, characterized in that, The subsea pipeline is located on the seabed and is distributed in a straight line.

6. The method for protecting subsea pipelines by integrating ship and plow coupling according to claim 1, characterized in that, In S4, the construction vessel, towing a tow cable, begins to pull the trenching plow, gradually lowering the plow boot height to reach the trenching depth, so that trenching operations can begin along the route.

7. The method for protecting subsea pipelines by integrating ship and plow coupling according to claim 1, characterized in that, In S4, adjust the mudguard of the trenching plow to achieve simultaneous trenching and backfilling.

8. The method for protecting subsea pipelines by integrating ship and plow coupling according to claim 1, characterized in that, In S4, when the ditching plow is about to reach the ditch exit point, the ditching plow raises its plow boot to allow the ditching plow to complete the exit.

9. The method for protecting subsea pipelines by integrating ship and plow coupling according to claim 1, characterized in that, In S5, the pipe is re-clamped, the support frame is opened, the subsea pipeline is placed on the seabed, the pipe gripper is activated, and the trenching operation is completed.

10. The method for protecting subsea pipelines by integrating ship and plow coupling according to claim 1, characterized in that, In S2, before the trenching plow performs pipe-holding operations, it must be positioned directly above the subsea pipeline, and the positioning accuracy of the front and rear rollers of the trenching plow must be less than or equal to 0.5 meters.

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