Unpowered semi-submersible platform offshore mooring method

Abstract

The application discloses a kind of offshore mooring methods of unpowered semi-submersible platform, through S1, mooring point selection;S2, the selection of mooring form;S3, the selection of mooring rope;S4, command system;S5, early preparation;S6, semi-submersible platform advance;S7, semi-submersible platform cable;To complete offshore mooring of unpowered semi-submersible platform;The application relates to the field of offshore unpowered semi-submersible platform mooring.The offshore mooring method of unpowered semi-submersible platform does not need to carry out personnel overboarding operation when floating platform is in unstable state, can reduce the risk of field operation, avoids the risk of personnel overboarding to semi-submersible platform in not completely stable state, avoids that traditional offshore mooring technology of unpowered semi-submersible platform is multiple tugboats collaborative operation until the installation operation of semi-submersible platform is completed, avoids long time multi-ship collaborative operation to stabilize semi-submersible platform high-difficulty operation.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of offshore unpowered semi-submersible platform mooring, in particular to a method for offshore mooring of unpowered semi-submersible platform. BACKGROUND

[0002] With the development of science and technology, offshore equipment development gradually develops towards deep sea equipment, and as the water depth increases, the construction cost and difficulty of fixed foundation work platform also increase; the semi-submersible platform is free from the constraints of complex seabed and geology, is less affected by water depth, and can greatly reduce the construction cost and difficulty, and will gradually become the trend of development of deep sea equipment.

[0003] Nowadays, most of the semi-submersible platforms in China are unpowered platforms, which cannot be stabilized and have no related equipment for auxiliary mooring, and need to rely on ships to provide temporary mooring to ensure the relative stability of the semi-submersible platform; the traditional offshore mooring technology of unpowered semi-submersible platform mostly uses several tugboats to work cooperatively until the installation of the semi-submersible platform is completed; this method is difficult to control the risk, has high requirements for ships, needs more ships, and has high cost; therefore, it is of great significance for the development of China's marine industry to develop a safe and efficient mooring technology for unpowered semi-submersible platform. SUMMARY

[0004] The present application aims to overcome the technical difficulties of traditional mooring technology and provide a key technology for offshore mooring of unpowered semi-submersible platform, which is simple to operate, has low risk, low cost and high efficiency.

[0005] To achieve the above purpose, the present application is implemented by the following technical scheme: a method for offshore mooring of unpowered semi-submersible platform, specifically comprising the following steps:

[0006] S1, selection of mooring points: using the towing eye plate on the semi-submersible platform, anchor chain for connecting the semi-submersible platform and the foundation, etc. as mooring points;

[0007] S2, selection of mooring form: selecting a suitable mooring form according to the arrangement of the mooring pile;

[0008] S3, selection of mooring ropes: calculating the stress of each mooring rope, and selecting the most suitable mooring rope according to the results;

[0009] S4, command system: establishing a semi-submersible platform mooring operation command system to complete the construction content of the ship;

[0010] S5, preliminary preparation: hanging part of the mooring ropes on the mooring points of the semi-submersible platform in advance, and fixing the two ends of the mooring ropes on the main work ship in advance and connecting them with the corresponding mooring piles and winches;

[0011] S6, the semi-submersible platform is moved: when the water flow is slow, the mooring operation of the semi-submersible platform is performed;

[0012] S7, the semi-submersible platform is moored: when the mooring operation of the semi-submersible platform is performed, the mooring cable along the water flow direction is first completed, and then the remaining mooring cable is completed.

[0013] Preferably, the mooring cable in S2 includes a combination of cross mooring and "eight" cable or a mooring cable double mooring operation.

[0014] Preferably, the mooring cable in S3 is selected according to the actual sea environment, the stress of the semi-submersible platform, the ship position arrangement, the mooring point position, the mooring cable angle, the number of mooring cables and the stress of the semi-submersible platform, and the stress of each mooring cable is calculated.

[0015] Preferably, in S4, the command system is established, a commander is at the core, each operation ship is equipped with an operation captain, the commander is responsible for commanding each operation ship to operate, and the operation captain on each operation ship is responsible for completing the construction content of the ship.

[0016] Preferably, in S6, when the semi-submersible platform is moved, the semi-submersible platform is moved 2-3 hours before the flat tide period according to the information provided by the weather forecast.

[0017] Preferably, in S7, when the semi-submersible platform is moored, the mooring operation is completed by using the towing eye plate as the mooring point or the anchor chain as the mooring point.

[0018] Beneficial effects

[0019] The application provides a non-powered semi-submersible platform offshore mooring method. Compared with the prior art, the following beneficial effects are achieved:

[0020] 1. Personnel transfer operation is not required when the floating platform is in an unstable state, the risk of on-site operation can be reduced, and the risk of personnel transfer to the semi-submersible platform in an unstable state is avoided;

[0021] 2. Part of the mooring cable is hung on the mooring point with a high position such as an anchor chain, the high-altitude operation is converted into water operation, the work boat is used as the operation platform for the mooring cable docking, the construction difficulty is further reduced, the construction efficiency is improved, the cost is reduced, and the limitation of the semi-submersible platform fixed mooring point on the mooring mode is reduced;

[0022] 3. The mooring cable is connected with the tugboat, the mooring operation and the tugboat connection are simplified into one step, the process is reduced, and the construction efficiency is improved.

[0023] 4. Avoid the traditional unpowered semi-submersible platform mooring technology more use several tugboats cooperative operation until the completion of the semi-submersible platform installation operation, circumvents the long time multi-ship cooperative operation stable semi-submersible platform high difficulty operation, at the same time reduces the influence of complex sea conditions on semi-submersible platform mooring operation. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 Flow chart of the semi-submersible platform mooring method of the present application; DETAILED DESCRIPTION

[0025] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0026] Please refer to Figure 1 The present application provides a technical solution: a semi-submersible platform mooring method, specifically comprising the following steps:

[0027] S1, selection of mooring points: when selecting mooring points, it is not necessary to be limited to mooring bitts on the semi-submersible platform, and towing eye plates, anchor chains for connecting the semi-submersible platform and the foundation, etc. on the semi-submersible platform can be used as mooring points, which can reduce the included angle of the mooring rope in the vertical direction, reduce the requirements on the mooring rope, and improve safety.

[0028] S2, selection of mooring form: selecting a suitable mooring form according to the arrangement of the mooring bitts;

[0029] Firstly, the combination of cross mooring and "eight" mooring is selected to improve the stability of the semi-submersible platform.

[0030] Secondly, the mooring rope is doubled for mooring operation, one end of the mooring rope is fixed to the mooring bitt of the main work ship, and the other end is connected with the winch, which can reduce the pressure of the mooring rope, and the position of the semi-submersible platform can be adjusted by operating the winch.

[0031] S3, selection of mooring rope: according to the flow velocity of the construction sea area collected in advance and the parameters of the semi-submersible platform, the stress condition of the semi-submersible platform under the most unfavorable load condition is calculated, then the stress of each mooring rope is calculated combined with the ship position arrangement, the mooring point position, the mooring rope angle, the number of mooring ropes and the stress condition of the semi-submersible platform, and the most suitable mooring rope is selected according to the results. The factors that need to be considered when selecting the mooring rope include: working load, length, material, diameter, operability, etc.

[0032] S4, command system: establish a semi-submersible platform mooring operation command system, with a total commander as the core, each operation ship is equipped with an operation team leader, the total commander is responsible for commanding each operation ship to operate, and the operation team leader on each operation ship is responsible for completing the construction content of the ship.

[0033] S5, preliminary preparation:

[0034] First, part of the mooring rope is hung on the mooring point of the semi-submersible platform in advance, which can reduce the high-altitude operation into water operation, reduce the operation difficulty and risk;

[0035] Second, fix the two ends of the mooring rope on the main operation ship in advance and connect them with the corresponding mooring pile and winch; improve the efficiency of the mooring operation and reduce the construction risk.

[0036] S6, semi-submersible platform advance: the influence of tidal current on semi-submersible platform is large, so the mooring operation of semi-submersible platform should be carried out when the current is slow, so as to ensure the safety of construction, therefore, according to the information provided by the weather forecast, the semi-submersible platform advance work should be started 2-3 hours before the flat tide period.

[0037] S7, semi-submersible platform mooring:

[0038] First, when carrying out the mooring operation of semi-submersible platform, the mooring operation of the mooring rope along the direction of water flow is preferentially completed, which can help the semi-submersible platform to resist the influence of water flow movement, and then the mooring operation of the remaining mooring rope is carried out;

[0039] Second, when the towing eye plate is used as the mooring point, the towing operation is carried out by using the tugboat connected with the towing eye plate, the main towing rope is put out and the ship is moved to the side of the main operation ship, the end of the corresponding mooring rope is pulled to the deck of the tugboat, then the main towing rope is reeled and the ship is moved synchronously, the long hair cable is fished to the deck and connected with the mooring rope, the mooring operation of the mooring rope is completed at the same time.

[0040] Third, when the anchor chain is used as the mooring point, the waist of the mooring rope on the main operation ship is pulled to the accessory of the pre-hung mooring rope end by the work boat, the two sections of mooring rope are butt jointed on the work boat, and the mooring operation is completed.

[0041] In summary, the mooring point is selected from the towing eye plate on the semi-submersible platform, anchor chain for connecting the semi-submersible platform and the foundation, etc., the mooring operation is performed in the mode of combination of cross mooring and "eight" mooring or the form of double mooring rope selection, the position of the semi-submersible platform is adjusted by operating the winch, the risk of on-site operation can be reduced without personnel over-boarding operation when the floating platform is in an unstable state, then the appropriate mooring rope is selected, then the semi-submersible platform mooring operation command system is established, the total commander is taken as the core, each operation ship is equipped with an operation captain, the total commander is responsible for commanding the operation of each operation ship, and the operation captain on each operation ship is responsible for completing the construction content of the ship; the mooring rope is hung on the semi-submersible platform mooring point in advance, the high-altitude operation can be converted into water operation, the operation difficulty and risk are reduced, the two ends of the mooring rope are fixed on the corresponding mooring pile and winch in advance on the main operation ship; the efficiency of the mooring operation is improved, the construction risk is reduced, the mooring operation of the semi-submersible platform is performed when the water flow is slow, so that the safety of the construction is ensured, part of the mooring rope is hung on the mooring point with a high position such as the anchor chain in advance, the high-altitude operation is converted into water operation, the work boat is taken as the operation platform for docking the mooring rope, the construction difficulty is further reduced, the construction efficiency is improved, and the cost is reduced; when the semi-submersible platform mooring operation is performed, the mooring operation of the mooring rope along the water flow direction is preferentially completed, which can help the semi-submersible platform to resist the influence of water flow movement, and then the mooring operation of the remaining mooring ropes is performed; when the towing eye plate is taken as the mooring point, the mooring operation is performed by using the tugboat connected with the towing eye plate, the main towing rope is released by the tugboat, the tugboat is moved to the side of the main operation ship, the end of the corresponding mooring rope is pulled to the deck of the tugboat, the main towing rope is reeled in and the tugboat is moved synchronously, the mooring rope is connected with the mooring rope after the mooring rope is fished to the deck, the mooring rope is connected with the mooring rope, the mooring operation of the mooring rope is completed, when the anchor chain is taken as the mooring point, the mooring rope waist of the main operation ship is pulled to the end of the pre-hung mooring rope by the work boat, the two mooring ropes are docked on the work boat, and the mooring is completed; the mooring rope is connected with the mooring rope by using the mooring rope connected with the tugboat, the mooring operation and the tugboat are simplified into one step, the process is reduced, the construction efficiency is improved, and finally the semi-submersible platform is positioned on the sea.

[0042] Meanwhile, the contents not described in detail in the specification all belong to the prior art known to those skilled in the art.

[0043] It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting; it is not intended to exclude myriad other embodiments of the present application that other inventors can develop based on the same general inventive concepts embodied by the described embodiments. That is, although the present application is described in terms of particular embodiments and illustrative figures, it should be apparent that the scope of the present application is not limited to these specific embodiments.

[0044] While the embodiments of the application have been shown and described herein, it will be understood by those skilled in the art that many changes, modifications, substitutions and alterations to these embodiments can be made without departing from the spirit and scope of the present application, which is defined by the appended claims and their equivalents.

Claims

1. A method of mooring an unpowered semi-submersible platform at sea, characterised in that: Specifically comprising the following steps: S1, selecting mooring points: using the towing eye plate on the semi-submersible platform and the anchor chain for connecting the semi-submersible platform and the foundation as mooring points; S2, selecting mooring forms: selecting appropriate mooring forms according to the arrangement of mooring piles; S3, selecting mooring ropes: calculating the force of each mooring rope and selecting the most appropriate mooring rope according to the results; S4, establishing a command system: establishing a mooring operation command system of the semi-submersible platform to complete the construction content of the ship; S5, preliminary preparation: hanging part of the mooring ropes on the mooring points of the semi-submersible platform in advance, and fixing the two ends of the mooring ropes on the main work ship in advance; S6, advancing the semi-submersible platform: selecting a slow current to perform the mooring operation of the semi-submersible platform; S7, mooring the semi-submersible platform: first completing the mooring operation of the mooring ropes along the direction of the current, and then completing the mooring operation of the remaining mooring ropes; The mooring form in step S2 includes the combination of cross mooring and "eight" mooring or the mooring operation of double mooring ropes; In step S3, the selection of the mooring rope is based on the actual sea environment, the force of the semi-submersible platform, the arrangement of the ship, the position of the mooring point, the angle of the mooring rope, the number of the mooring rope, and the force of the semi-submersible platform to calculate the force of each mooring rope; In step S4, when establishing the command system, a total commander is at the core, each work ship is equipped with a work team leader, the total commander is responsible for commanding the work of each work ship, and the work team leader on each work ship is responsible for completing the construction content of the ship.

2. A method of mooring an un-powered semi-submersible platform at sea as claimed in claim 1, characterised in that: In S6, when the semi-submersible platform advances, the work is started 2-3 hours before the flat tide period according to the information provided by the weather forecast.

3. A method of mooring an un-powered semi-submersible platform at sea as claimed in claim 1, characterised in that: In S7, when the semi-submersible platform is moored, the towing eye plate is used as the mooring point or the anchor chain is used as the mooring point to complete the mooring operation.

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