A submarine cable towing head and its application

Abstract

The present invention discloses a submarine cable towing head and its application, comprising a submarine cable and a steel pipe with the same diameter as the main pipeline, a submarine cable pin is welded and fixed at the port adjacent to the right side of the steel pipe, two cable holes are symmetrically opened on the wall of the main pipeline along its axis, and the two cable holes are located at the port on the left side of the steel pipe. The submarine cable passes through the cable holes and extends to the inside of the steel pipe and bypasses the submarine cable pin and is clamped by a U-shaped buckle after bending back. The present invention adopts the same hole crossing of the submarine cable and the main pipeline to reduce the number of directional drilling crossing construction of the optical cable pipe, and avoids the tedious work of secondary displacement of the drilling rig, secondary removal and installation of the anchor, etc. In particular, the directional drilling crossing project with a long crossing distance and complex geological structure can effectively shorten the construction period.

Description

Technical Field

[0001] The invention relates to the field of pipeline construction engineering, and in particular to a submarine cable towing head and application thereof. Background Art

[0002] In the directional drilling construction of gas pipelines, according to the directional drilling industry practices and relevant specifications, the main pipeline + accompanying optical cable method is adopted. The galvanized steel pipe is passed through separately, and the directional drilling entry angle and curvature radius are the same as the main pipeline. The crossing axis is parallel to the axis of the main pipeline and is located about 10m to the right of the main pipeline in the direction of airflow (not less than 6m). A steel wire is pre-placed in the galvanized steel pipe. After the galvanized steel pipe is pulled back, the pre-placed steel wire is used to pull two silicon core tubes (one for use and one for backup). After the silicon core tube is pulled, the cable is blown. After the cable core attenuation test meets the technical requirements, it is connected with the ordinary optical cable in general areas.

[0003] However, in directional drilling with limited space and complex geological structure, it is difficult to meet the construction period and technical requirements within the scheduled construction period due to the difficulty of outsourcing, high compensation amount and many unforeseen factors in complex strata. The main pipeline + accompanying optical cable method cannot meet the requirements of relevant specifications and construction. In view of this, the present invention proposes a submarine cable tow head and its application. Summary of the invention

[0004] The object of the present invention is to provide a submarine cable towing head and application thereof to solve the problems raised in the above background technology.

[0005] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a submarine cable towing head, comprising a submarine cable and a steel pipe with the same diameter as a main pipeline, a submarine cable pin is welded and fixed to the inside of the steel pipe adjacent to the port on the right side thereof, two cable drawing holes are symmetrically opened on the wall of the main pipeline along its axial direction, and the two cable drawing holes are located at the port on the left side of the steel pipe. The submarine cable extends through the cable drawing holes to the inside of the steel pipe, bypasses the submarine cable pin, and is clamped by a U-shaped buckle after being bent back.

[0006] The present invention also proposes an application of a submarine cable tug, which is applied to directional drilling and crossing construction of a gas pipeline. The construction method is as follows:

[0007] Step 1: Production of submarine cable towing head;

[0008] Step 2: Use welding to firmly connect the two ends of the submarine cable tug to the main pipeline and the pipeline tug;

[0009] Step 3: The front end of the pipeline tug is connected to the traction device, and the submarine cable and the main pipeline are tractioned synchronously.

[0010] Preferably, the specific steps for making a submarine cable tow head are as follows: two circular holes with diameters being the same as the outer diameters of the submarine cable pins are punched on the steel pipe, the submarine cable pins are inserted into the interior of the steel pipe, 500mm in front of the connection point of the main pipeline, a 350mmx35mm groove is cut forward and a smooth groove is punched in the forward direction to form a cable hole, the submarine cable passes through the steel pipe from the cable hole, bypasses the submarine cable pins and then bends back, the bent submarine cable is clamped with a U-shaped buckle, and finally the connection between the submarine cable pin and the steel pipe is welded.

[0011] Preferably, in step 2, before welding the submarine cable towing head and the main pipeline, a blind plate is welded between the submarine cable towing head and the main pipeline.

[0012] Preferably, after step 2 is completed, the submarine cable located outside the submarine cable towing head is clamped on the outer wall of the main pipeline through the submarine cable fixing plate, and the submarine cable fixing plate is welded to the main pipeline using an elastic iron sheet.

[0013] Preferably, after step three is completed, the submarine cable is connected to the ordinary optical cable after the main pipeline is pulled back from the directional drilling hole for at least five meters.

[0014] Compared with the prior art, the present invention provides a submarine cable towing head and its application, which has the following beneficial effects:

[0015] (1) The present invention adopts the same hole crossing of the submarine cable and the main pipeline to reduce the number of directional drilling crossing construction of the optical cable pipe, and avoid the tedious work of secondary displacement of the drilling rig and secondary removal and installation of the anchor. In particular, the directional drilling crossing project with a long crossing distance and complex geological structure can effectively shorten the construction period.

[0016] (2) Compared with the directional drilling of ordinary optical cable (galvanized steel pipe) pipelines, the directional drilling of submarine cables can effectively reduce project investment, save costs, and have significant economic benefits.

[0017] (3) Directional drilling uses the synchronous directional drilling and pulling back technology solution of submarine cable and main pipeline in the same hole, which can effectively reduce the difficulty of public relations coordination (outsourcing), improve construction safety, shorten the construction period, and has obvious social benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0019] Figure 1 This is a schematic diagram of the connection between the submarine cable tug, the pipeline tug and the main pipeline in an embodiment of the present invention;

[0020] Figure 2 This is a schematic diagram of the structure of a submarine cable tow head in an embodiment of the present invention;

[0021] Figure 3 for Figure 1 Schematic diagram of the pipe after being cut along the axial direction.

[0022] In the figure: 1. Steel pipe; 2. Main pipeline; 3. Pipeline tug; 4. Reinforcement plate; 5. Submarine cable; 6. Submarine cable fixing plate; 7. Cable threading hole; 8. Submarine cable threading pin; 9. U-shaped buckle; 10. Blind plate. DETAILED DESCRIPTION

[0023] The technical solutions 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 only a part of the embodiments of the present invention, rather than all the embodiments. The components of the embodiments of the present invention generally described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents the selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present invention.

[0024] like Figure 2 As shown, the present embodiment discloses a submarine cable towing head, comprising a submarine cable 5 and a steel pipe 1 having the same diameter as a main pipe 2, wherein a submarine cable pin 8 is welded and fixed to the inner side of the steel pipe 1 adjacent to the port on the right side thereof, and two cable threading holes 7 are symmetrically provided on the pipe wall of the main pipe 2 along its axial direction, and the two cable threading holes 7 are located at the port on the left side of the steel pipe 1, and the submarine cable 5 extends through the cable threading holes 7 to the inner side of the steel pipe 1 and bypasses the submarine cable threading pin 8 and is then clamped by a U-shaped buckle 9 after being bent back.

[0025] The present application applies the submarine cable 5 to the directional drilling crossing construction of the gas pipeline, and the submarine cable 5 and the main pipeline 2 are pulled back together in the same directional drilling hole.

[0026] Before construction, first make a submarine cable tug, and punch two circular holes on the steel pipe 1 with the same diameter as the outer diameter of the submarine cable pin 8. The submarine cable pin 8 is 350mm away from the connection point of the pipeline tug 3 to ensure that it can withstand sufficient tension. The submarine cable pin 8 is made of seamless steel pipe. The submarine cable pin 8 is inserted into the interior of the steel pipe 1. 500mm in front of the connection point of the main pipeline 2, a 350mmx35mm groove is cut forward and a smooth groove is made in the forward direction to form a cable hole 7. The smooth groove can prevent the submarine cable 5 from being damaged. The submarine cable 5 passes through the steel pipe 1 from the cable hole 7, bypasses the submarine cable pin 8, and then bends back. The U-shaped buckle 9 is used to clamp the bent submarine cable 5. Finally, the connection between the submarine cable pin 8 and the steel pipe 1 is welded.

[0027] After the submarine cable tug is manufactured, the two ends of the submarine cable tug are respectively connected to the main pipeline 2 and the pipeline tug 3 by welding. Before the submarine cable tug is welded to the main pipeline 2, a blind plate 10 is welded between the submarine cable tug and the main pipeline 2. Since the main pipeline 2 is used to transmit gas, the welding blind plate 10 can prevent mud and gravel from entering the main pipeline 2 through the cable hole 7. After the submarine cable tug is welded to the main pipeline 2 and the pipeline tug 3, the submarine cable 5 located outside the submarine cable tug is clamped on the outer wall of the main pipeline 2 through the submarine cable fixing plate 6, and the submarine cable fixing plate 6 is welded to the main pipeline 2 with an elastic iron sheet.

[0028] The front end 4 of the pipeline tug 3 is connected to the backhaul device, and the submarine cable 5 and the main pipeline 2 are backhauled synchronously. Since the submarine cable 5 at the submarine cable pin 8 is subjected to a large tensile force, the submarine cable 5 in the submarine cable tug will be damaged. In order to ensure the communication quality of the submarine cable 5, the damaged part of the submarine cable 5 needs to be cut off. Therefore, when backhauling, the pipeline is required to be dragged out more than 5m, and the submarine cable 5 is connected with the ordinary optical cable in the hand holes on both sides. In addition to the fixed connection on the submarine cable tug, the rest of the submarine cable 5 is in a free state (the submarine cable 5 is placed below or on the side of the main pipeline 2) and backhauled together with the main pipeline 2.

[0029] In addition, this application further demonstrates the remarkable effect of the submarine cable towing head through specific construction project examples. In the Qingning gas pipeline project, the directional drilling of the Touxi River adopts the design of directional drilling through the same hole of the submarine cable and the main pipeline. The application effect analysis is as follows:

[0030] Construction period

[0031] The use of submarine cables and main pipelines in the same hole can reduce the number of directional drilling construction of optical cable pipes, avoid the tedious work of secondary displacement of drilling rigs, secondary removal and installation of anchors, etc. Especially for directional drilling crossing projects with long crossing distances and complex geological structures, the construction period can be effectively shortened. In the Qingning gas pipeline project, the owner required the total construction period of Touxi River directional drilling to be 20 days, because the stratum through which Touxi River directional drilling passes contains ginger stone locally. If the main pipeline and optical cable are separated by directional drilling, considering the construction safety, the optical cable guide crossing period is 5 days. After the optical cable guide hole is pulled back, the main pipeline crossing involves the positioning of the drilling rig and supporting equipment, axial measurement, drilling rig debugging and other processes. It is expected to complete the main pipeline guide hole + 7-level expansion + 2-level washing, and the safe and smooth completion of the pullback time is 20 days, and the total construction period reaches 25 days. The construction period required by the owner cannot be met.

[0032] In order to meet the construction period required by the owner, the construction plan of separate directional drilling of the main pipeline and the optical cable could not be adopted under the stratum containing ginger stone. Taking into account the safety of directional drilling construction, geological conditions of directional drilling crossing, compensation for directional drilling river occupation and other factors, the Touxi River directional drilling crossing project adopted the design plan of directional drilling crossing of submarine cable and main pipeline in the same hole.

[0033] The time for crossing the optical cable guide hole through the Touxi River directional drilling was 5 days, and the drilling rig relocation, anchor removal and installation took at least 3 days, saving a total of 8 days of construction time.

[0034] Construction risks

[0035] Directional drilling crossing projects use different crossing methods due to different geographical locations and on-site conditions. Based on the geotechnical report and actual on-site conditions, a detailed risk analysis is conducted and effective response measures are formulated. According to the geotechnical report data of Touxi River, the Touxi River submarine cable and the main pipeline synchronously towed back directional drill in the same hole carried out geological densification and supplementary survey before entering the site, and in conjunction with multiple departments, the complexity of the geological structure was further analyzed on the basis of the original geotechnical data, and the directional drilling crossing layer and depth were discussed and confirmed. Before construction, the construction unit's construction plan was reviewed, and combined with the design plan, a construction optimization plan was proposed to effectively reduce construction risks.

[0036] The directional drilling construction of the Touxihe submarine cable and the main pipeline in the same hole was carried out strictly in accordance with the construction plan. During the construction process, the connection of the fixed points, the specific gravity and viscosity of the mud, the pump pressure of the circulating pump, the stress release of the submarine cable and the speed of the pullback were strictly controlled. The pullback was successfully achieved within the 12-day construction period required by the owner. After the pullback was completed, the insulation performance of the optical cable was tested and fully met the technical requirements of the optical fiber attenuation coefficient ≤ 0.22dB / km.

[0037] Economic and social benefits

[0038] The directional drilling and crossing of ordinary optical cable (galvanized steel pipe) pipeline mainly includes galvanized steel pipe welding, anti-corrosion, drilling, back-pulling, crossing of two silicon core tubes (one for use and one for backup), blowing cables in silicon core tubes, etc. The overall construction cost of general optical cable directional drilling and crossing (galvanized steel pipe procurement fee, welding anti-corrosion fee, galvanized steel pipe directional drilling and crossing construction, silicon core tube crossing construction, blowing cables, optical cable material fee, etc.) is about 38,000 yuan / km. In addition, the directional drilling and crossing of ordinary optical cable requires an additional 10m wide land acquisition. According to the actual outsourcing compensation standard (economically developed areas), the land acquisition fee per kilometer (calculated according to the temporary compensation standard for two seasons) is 450,000 yuan / km. The comprehensive cost of ordinary optical cable directional drilling and crossing is 488,000 yuan / km. The overall cost of submarine cable directional drilling and crossing (submarine cable procurement fee, submarine cable tug material fee, submarine cable tug and submarine cable installation fee, etc.) is 245,200 yuan / km. The data shows that the cost of submarine cable directional drilling is about 50% lower than that of ordinary optical cable (galvanized steel pipe) pipeline directional drilling, which has significant economic benefits.

[0039] The National Pipeline Network Company has been established, and the construction of domestic natural gas pipelines will surely be carried out on a large scale. In addition, under the general environment of strengthening domestic infrastructure, the difficulty of public relations coordination (outsourcing) is increasing. The use of directional drilling and pulling back technology with submarine cables and main pipelines in the same hole can reduce the workload of public relations coordination on the one hand, and reduce the land acquisition costs of 10m width on the other hand. In economically developed areas (Beijing, Shanghai, Guangzhou, Jiangsu and Zhejiang), the land acquisition costs are high and the crossing positions are limited. When the pipeline passes through these areas, the directional drilling uses the synchronous directional drilling and pulling back technology solution of submarine cables and main pipelines in the same hole to effectively reduce the difficulty of public relations coordination (outsourcing), improve construction safety, shorten the construction period, and achieve obvious social benefits.

[0040] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. An application of a submarine cable towing head, characterized in that: The submarine cable towing head comprises a submarine cable (5) and a steel pipe (1) having the same diameter as the main pipeline (2). A submarine cable pin (8) is welded and fixed to the inner side of the steel pipe (1) adjacent to the right end thereof. Two cable threading holes (7) are symmetrically provided on the wall of the main pipeline (2) along its axial direction. The two cable threading holes (7) are located at the left end of the steel pipe (1). The submarine cable (5) passes through the cable threading holes (7) and extends into the inner side of the steel pipe (1), bypasses the submarine cable pin (8), bends back, and is clamped by a U-shaped buckle (9). A blind plate (10) is welded between the steel pipe (1) and the main pipeline (2). The submarine cable towhead is used in the directional drilling and crossing construction of gas pipelines. The construction method is as follows: Step 1: Production of submarine cable towing head; Step 2: Use welding to firmly connect the two ends of the submarine cable tug to the main pipeline (2) and the pipeline tug (3); Step 3: The front end (4) of the pipeline tug (3) is connected to the hauling device, and the submarine cable (5) and the main pipeline (2) are hauled back synchronously; The specific steps of making the submarine cable towing head are as follows: two circular holes with diameters of the same outer diameter as the submarine cable pin (8) are punched on the steel pipe (1); the submarine cable pin (8) is inserted into the steel pipe (1); 500 mm in front of the connection point of the main pipeline (2), a 350 mm x 35 mm groove is made forward and a rounded and smooth groove is punched in the forward direction to form a cable hole (7); the submarine cable (5) is passed through the cable hole (7) into the steel pipe (1), bypasses the submarine cable pin (8), and then bends back; a U-shaped buckle (9) is used to clamp the bent submarine cable (5); and finally the connection between the submarine cable pin (8) and the steel pipe (1) is welded; In step 2, before welding the submarine cable towing head and the main pipeline (2), a blind plate (10) is welded between the submarine cable towing head and the main pipeline (2); After step 2 is completed, the submarine cable (5) located outside the submarine cable towing head is clamped on the outer wall of the main pipeline (2) through the submarine cable fixing plate (6), and the submarine cable fixing plate (6) is welded to the main pipeline (2) using an elastic iron sheet; After step 3 is completed, the main pipeline (2) is pulled back from the directional drilling hole for at least five meters, and then the submarine cable (5) is connected to the ordinary optical cable.

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