Synchronous pull-back method for horizontal directional drilling submarine pipeline

Abstract

The invention discloses a synchronous pull-back method for a horizontal directional drilling submarine pipeline, which comprises the following steps of: installing a pull-back tool at the tail end of a drill rod, and discarding the seabed; leveling a pipe-laying ship stinger; a submarine pipeline is prefabricated to the stern through an operation line, and a pull-back seal head is welded; the pipe laying ship is anchored in place; the salvage pull-back tool is connected with the submarine pipeline; the stinger is adjusted, the tensioner is started, and the submarine pipeline reaches the preset tension; submarine pipelines are prefabricated through the pipe laying ship; the drilling machine pulls the drill rod to drive laying of the submarine pipeline; front and back anchoring is carried out, the pipe laying ship is adjusted, and the synchronism of submarine pipeline prefabricated launching and drill rod drawing water outlet is achieved; welding a termination end socket, connecting an A / R cable, opening a tensioner, and performing tension conversion; and releasing the back-dragging tool and unearthing the submarine pipeline. According to the synchronous back-dragging method for the horizontal directional drilling submarine pipeline, only anchoring operation of a pipe laying ship is needed, large-area construction occupying the sea is not needed, and the contradiction of using the sea is reduced.

Description

Technical Field

[0001] The invention belongs to the field of marine engineering submarine pipeline laying, and in particular relates to a synchronous backhaul method for horizontally directional drilled submarine pipelines. Background Art

[0002] When laying submarine pipelines, horizontal directional drilling technology is used to pass the submarine pipeline through the strata due to reasons such as crossing waterways, crossing existing pipes and cables, and interfering with ecological red lines. How to safely and efficiently complete the directional drilling and towing construction of the submarine pipeline is a highly difficult technology and a key link in determining the success or failure of a directional drilling crossing project.

[0003] When horizontal directional drilling and towing back construction is carried out on submarine pipelines, a common method is to prefabricate the submarine pipeline that needs to be towed back in advance, temporarily abandon it on the seabed or tie it to a buoy to float on the sea surface temporarily, and then tow the submarine pipeline back as a whole after the drill rod is connected to the sea pipe.

[0004] However, this pull-back method has the following shortcomings: (1) The prefabricated submarine pipeline will occupy a large sea area, affecting passing ships or other marine activities. The longer the submarine pipeline, the greater the impact; (2) If pipelines temporarily abandoned on the seabed cannot be towed back in time due to weather or other factors, there is a risk of being hit by falling anchors or objects; (3) When a pipeline temporarily abandoned on the seabed is towed back, the larger sliding friction resistance and seabed adsorption force will increase the towing force, which may exceed the pulling force limit of the drilling rig and lead to the risk of towing failure. (4) When temporarily abandoned on the seabed, if the protection is not in place or the seabed topography is incorrectly detected during the towing back of the pipeline, the coating on the outer surface of the submarine pipeline may be scratched and damaged; (5) When a submarine pipeline temporarily floats on the sea surface with a moored buoy, it will swing laterally under the action of waves when being towed back, making it difficult to limit its position, and there is a risk of breaking the drill pipe; (6) When a submarine pipeline is temporarily floating on the sea surface with a buoy tied to it, the buoys need to be removed one by one during towing, which is a lot of work.

[0005] Therefore, it is urgent to design a synchronous pullback method for horizontal directional drilling of submarine pipelines to solve the above-mentioned problems of directional drilling and pullback construction of submarine pipelines. Summary of the invention

[0006] In order to solve the technical problem mentioned in the background technology that the overall prefabricated submarine pipeline will occupy a large sea area, when the pipeline temporarily abandoned on the seabed is towed back, the large sliding friction resistance and the seabed adsorption force will cause the towing back force to increase, and there is a risk of exceeding the pulling limit of the drilling rig and causing the towing back to fail; when the submarine pipeline temporarily floats on the sea surface tied with a buoy, the buoys need to be removed one by one during towing back, which causes a large workload. A synchronous towing back method for submarine pipelines in horizontal directional drilling is provided to solve the problem of directional drilling towing back construction of submarine pipelines.

[0007] To achieve the above-mentioned purpose, the specific technical scheme of the synchronous pulling back method of horizontal directional drilling submarine pipeline of the present invention is as follows: A synchronous towing method for a horizontally directional drilled submarine pipeline comprises the following steps: S1. Install a pull-back tool at the end of the drill pipe and abandon it on the seabed; S2. Leveling of the pipe-laying vessel's stinger; S3, prefabricate the submarine pipeline to the stern of the ship, weld and tow back the head; S4. The pipe-laying vessel drops anchor and takes position; S5, salvage and towing tools, connected to the submarine pipeline; S6. Adjust the stinger and start the tensioner to make the submarine pipeline reach the preset tension; S7. Prefabricate submarine pipelines on pipe-laying vessels; S8, the drilling rig pulls out the drill pipe to drive the laying of the submarine pipeline; S9, front and rear anchors are cut, and the pipe-laying vessel is adjusted to achieve synchronization between the launching of submarine pipeline prefabrication and the pulling out of the drill pipe; S10, weld the termination head, connect the A / R cable, open the tensioner, and perform tension conversion; S11. Release the towing tool and unearth the submarine pipeline.

[0008] Furthermore, in S1, a special pull-back tool is installed at the end of the drill pipe, and a float is tied and temporarily abandoned at the designed coordinate point of the submarine pipeline pull-back.

[0009] Further, in S2, the pipe-laying vessel adjusts the angle of the stinger to a horizontal posture of 0 degrees.

[0010] Furthermore, in S3, the pipe-laying vessel operation line prefabricates the submarine pipeline so that the front end of the submarine pipeline reaches the last roller at the end of the hosting rack; a special pull-back head is welded at the front end of the submarine pipeline, and NDT non-destructive testing is performed to ensure that the weld quality is qualified.

[0011] Furthermore, in S5, the temporarily abandoned drill pipe is salvaged using the crane on the pipe-laying vessel, and the end of the drill pipe is connected to the front end of the subsea pipeline using a clamping ring to complete the preparation for the towing back construction.

[0012] Further, in S6, the pipe-laying vessel's stinger is released to adjust the stinger to a normal pipe-laying angle; the pipe-laying vessel's tensioner is started to initiate the initial towing back and laying of the submarine pipeline, and the pipe-laying vessel slowly advances after twisting the anchor so that the tension on the drill pipe reaches the designed tension value; the drilling rig starts to pull out the drill pipe, pulling out a drill pipe of no less than 9.6 meters each time.

[0013] Furthermore, in S7, the pipe-laying vessel operation line carries out welding, non-destructive testing, and node anti-corrosion work on the submarine pipeline, prefabricating a submarine pipeline of no less than 12.2 meters each time.

[0014] Furthermore, in S9, by adjusting the front and rear anchors, the pipe-laying vessel is adjusted to move forward or backward to achieve synchronization of the submarine pipeline towing back.

[0015] Furthermore, in S10, after the last submarine pipeline is prefabricated, a termination cap is welded at its end, the A / R cable is connected, the tensioner is opened, the tension is converted, and the termination pullback is completed.

[0016] Furthermore, in S11, the clamping ring connecting the end of the drill pipe and the front end of the submarine pipeline is released to complete the horizontal directional drilling submarine pipeline towing construction.

[0017] The synchronous towing back method of horizontal directional drilling submarine pipeline of the present invention has the following advantages: This method only requires the pipe-laying vessel to drop anchor for construction, and does not require large-scale sea occupation for construction, thus reducing conflicts in the use of the sea; each prefabricated submarine pipeline can be immediately buried, reducing the risk of external damage to the submarine pipeline and ensuring the safety of the submarine pipeline; the towing back construction process is similar to the conventional initial laying of submarine pipelines, with more mature construction experience and higher construction reliability. This application can achieve synchronization between drill pipe disassembly and submarine pipe prefabrication, with high construction efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a flow chart of the synchronous towing back method of horizontal directional drilling submarine pipeline of the present invention; Figure 2 It is a schematic diagram of the entry point and exit point of the drill rod in the synchronous backhaul method of horizontal directional drilling of submarine pipelines of the present invention; Figure 3 It is a schematic diagram of the structure of a pipe-laying vessel of the synchronous towing back method of horizontal directional drilling of submarine pipelines of the present invention; Figure 4 It is a schematic diagram of the entry point and exit point of the submarine pipeline in the synchronous backhaul method of the horizontal directional drilling submarine pipeline of the present invention.

[0019] Description of the markings in the figure: 1. Drilling rig; 2. Drill pipe; 3. Towing tool; 4. Float; 5. Pipe-laying vessel; 6. Stinger; 7. Subsea pipeline; 8. Towing head; 9. Anchor; 10. Crane; 11. Operating line; 12. Tensioner; 13. Clamp; 14. Termination head; 15. A / R cable. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0021] Those skilled in the art will appreciate that, although some embodiments herein include certain features included in other embodiments but not other features, the combination of features of different embodiments is meant to be within the scope of the present invention and form different embodiments. For example, in the claims, any one of the claimed embodiments may be used in any combination.

[0022] Please refer to the attached Figure 1 To Attachment Figure 4 The synchronous pulling back method of horizontally directional drilled submarine pipeline of the present invention is described.

[0023] As a preferred embodiment, Figures 1 to 4 As shown, the synchronous towing back method of the horizontal directional drilling submarine pipeline in the present invention should adopt the following steps to realize the synchronous towing back of the prefabricated submarine pipeline by the pipe-laying ship operation line in conjunction with the horizontal directional drilling: S1. Install a special backhaul tool 3 at the end of the drill pipe 2, and tie the float 4 to temporarily abandon it at the designed coordinate point of the submarine pipeline backhaul; S2, the pipe-laying vessel 5 adjusts the angle of the stinger 6 to a horizontal posture of 0 degrees; S3, the pipe-laying vessel 5 operating line 11 prefabricates the submarine pipeline 7, so that the front end of the submarine pipeline 7 reaches the last roller at the end of the stinger 6; S4. Weld a special pull-back head 8 at the front end of the submarine pipeline 7, and perform NDT non-destructive testing to ensure the quality of the weld; S5, pipe-laying vessel 5 drops anchor 9 and takes position; S6. Use the crane 10 on the pipe-laying vessel 5 to salvage the temporarily abandoned drill pipe 2, and use the clamp ring 13 to connect the end of the drill pipe 2 to the front end of the sea pipe 7, completing the preparation for the towing back construction; S7, releasing the pipe-laying vessel 5 and the stinger 6, so that the stinger 6 is adjusted to a normal pipe-laying angle; S8, start the tensioner 12 of the pipe-laying vessel 5 to start the initial towing back laying of the submarine pipeline 7, and the pipe-laying vessel 5 twists the anchor 9 and moves forward slowly, so that the tension on the drill pipe 2 reaches the designed tension value; S9, the drilling rig 1 starts pulling out the drill pipe 2, pulling out a 9.6-meter drill pipe each time. At the same time, the pipe-laying vessel 5 operation line 11 performs welding, non-destructive testing, and node anti-corrosion work on the submarine pipeline 7, prefabricating a 12.2-meter submarine pipeline each time;

[0024] S10, front and rear anchors 9 are twisted to adjust the pipe-laying vessel 5 to move forward or backward to achieve synchronization of the submarine pipeline 7; S11, when the last sea pipe is prefabricated, a termination cap 14 is welded at its end, the A / R cable 15 is connected, the tensioner 12 is opened, the tension is converted, and the termination backhaul is completed; S12: Release the clamping ring 13 connecting the end of the drill pipe 2 and the front end of the submarine pipeline 7, and complete the horizontal directional drilling submarine pipeline towing construction; Preferably, the submarine pipeline towing back design coordinate point in S1 is usually extended by a certain length along the submarine pipeline design route at the directional drilling excavation point. The extended length should not be too large and is determined by the bending limit of the drill pipe used in the construction, that is, to ensure that the drill pipe will not be bent and damaged after the end of the drill pipe is salvaged out of the water.

[0025] The height of each set of rollers on the S2 pipe rack should be adjusted according to the design height during normal pipe laying.

[0026] In S3, the front end of the submarine pipeline should be as close to the end of the stinger as possible.

[0027] When the pipe-laying vessel in S5 is anchored in place, the end of the stinger should be located directly above the end of the drill pipe temporarily abandoned on the seabed to facilitate salvage, while ensuring that the central axis of the pipe-laying vessel's operating line is in a straight line with the horizontal directional drilling seabed pipeline route.

[0028] S2, S3, and S4 should be performed simultaneously with step 5 as much as possible to save the preparation time for the return pull.

[0029] The retaining ring in S6 needs to be welded to the pin to prevent the pin from loosening during the back-pulling process.

[0030] When the tension on the drill pipe in S8 reaches the designed tension value, the pipe-laying vessel stops moving forward.

[0031] After the S9 towing back begins, 24-hour uninterrupted operation is required to ensure the welding quality of the submarine pipeline, avoid the occurrence of unqualified welding repairs, and prevent the risk of towing back interruption.

[0032] There are two main methods to achieve pull-back synchronization in S10: the first is to pull out one drill pipe, prefabricate one sea pipe, and the pipe-laying vessel moves forward 2.6 meters; the second is to pull out two drill pipes continuously, prefabricate one sea pipe, and the pipe-laying vessel moves back 7 meters. The two operation methods are used alternately.

[0033] Synchronous towing back method for submarine pipeline based on horizontal directional drilling. This method only requires the pipe-laying ship to drop anchor for operation, and does not require large-scale sea construction, reducing conflicts in sea use; each prefabricated submarine pipeline can be immediately buried, reducing the risk of submarine pipeline damage from the outside and ensuring the safety of submarine pipeline; the towing back construction process is similar to the conventional initial laying of submarine pipelines, the construction experience is relatively mature, and the construction reliability is higher. This application can achieve the synchronization of drill pipe disassembly and submarine pipe prefabrication, and the construction efficiency is high.

[0034] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A synchronous pull-back method for horizontal directional drilling of submarine pipelines, characterized in that: The following steps are involved: S1. Install a pull-back tool at the end of the drill pipe and abandon it on the seabed; S2. Leveling of the pipe-laying vessel's stinger; S3, prefabricate the submarine pipeline to the stern of the ship, weld and tow back the head; S4. The pipe-laying vessel drops anchor and takes position; S5, salvage and towing tools, connected to the submarine pipeline; S6. Adjust the stinger and start the tensioner to make the submarine pipeline reach the preset tension; S7. Prefabricate submarine pipelines on pipe-laying vessels; S8, the drilling rig pulls out the drill pipe to drive the laying of the submarine pipeline; S9, front and rear anchors are cut, and the pipe-laying vessel is adjusted to achieve synchronization between the launching of submarine pipeline prefabrication and the pulling out of the drill pipe; S10, weld the termination head, connect the A / R cable, open the tensioner, and perform tension conversion; S11. Release the towing tool and unearth the submarine pipeline.

2. The synchronous pulling back method of horizontal directional drilling submarine pipeline according to claim 1 is characterized in that: In S1, a special pull-back tool is installed at the end of the drill pipe, and the float is tied and temporarily abandoned at the designed coordinate point of the submarine pipeline pull-back.

3. The synchronous pulling back method for horizontal directional drilling of submarine pipeline according to claim 1 is characterized in that: In S2, the pipe-laying vessel adjusts the angle of the stinger to a horizontal posture of 0 degrees.

4. The synchronous pulling back method for horizontal directional drilling of submarine pipeline according to claim 1 is characterized in that: In S3, the pipe-laying vessel operation line prefabricates the submarine pipeline so that the front end of the submarine pipeline reaches the last roller at the end of the stinger; a special pull-back head is welded at the front end of the submarine pipeline, and NDT non-destructive testing is performed to ensure the quality of the weld.

5. The synchronous pulling back method for horizontal directional drilling of submarine pipeline according to claim 1 is characterized in that: In S5, the crane on the pipe-laying vessel was used to salvage the temporarily abandoned drill pipe, and the end of the drill pipe was connected to the front end of the subsea pipeline using a clamping ring to complete the preparation for the backhaul construction.

6. The synchronous pulling back method for horizontal directional drilling of submarine pipeline according to claim 1, characterized in that: In S6, the pipe-laying vessel's stinger is released to adjust the stinger to a normal pipe-laying angle; the pipe-laying vessel's tensioner is started to initiate the initial towing back and laying of the submarine pipeline, and the pipe-laying vessel slowly advances after twisting the anchor so that the tension on the drill pipe reaches the designed tension value; the drilling rig starts to pull out the drill pipe, pulling out a drill pipe of no less than 9.6 meters each time.

7. The synchronous pulling back method for horizontal directional drilling of submarine pipeline according to claim 1, characterized in that: In S7, the pipe-laying vessel operation line carries out welding, non-destructive testing, and node anti-corrosion work on submarine pipelines, prefabricating a submarine pipeline no less than 12.2 meters in length each time.

8. The synchronous pulling back method for horizontal directional drilling of submarine pipeline according to claim 1, characterized in that: In S9, by adjusting the front and rear anchors, the pipe-laying vessel is adjusted to move forward or backward to achieve synchronization of the submarine pipeline towing back.

9. The synchronous pulling back method for horizontal directional drilling of submarine pipeline according to claim 1, characterized in that: In S10, when the last submarine pipeline is prefabricated, a termination cap is welded at its end, the A / R cable is connected, the tensioner is opened, the tension is converted, and the termination pullback is completed.

10. The synchronous pulling back method for horizontal directional drilling of submarine pipeline according to claim 1, characterized in that: In S11, the clamping ring connecting the end of the drill pipe and the front end of the submarine pipeline is released to complete the horizontal directional drilling submarine pipeline pullback construction.

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