KR101358140B1 - Turret mooring system for offshore structure - Google Patents

Abstract

A turret mooring system for offshore structures is disclosed. Turret mooring system for offshore structures according to an embodiment of the present invention is a connection portion fixed in the water by the mooring line; A turret installed to rotate in the offshore structure, the turret having a connection groove for receiving the connection portion thereunder; And it is installed in the connection groove and includes a binding device for binding the connection portion entered into the connection groove.

Description

Turret mooring system for offshore structures {TURRET MOORING SYSTEM FOR OFFSHORE STRUCTURE}

The present invention relates to a turret mooring system for offshore structures capable of moving offshore structures after releasing mooring offshore structures in consideration of working conditions or mooring offshore structures.

Offshore structures, such as floating production storage offloading (FPSO) and floating storage offloading (FSO), perform their work while they are mooring at the sea. The mooring system is thus a device for mooring offshore structures to work at sea. By anchoring ropes, etc. from offshore structures to the sea floor, the offshore structures are moored to the working position.

Among the mooring systems is a turret mooring system that allows offshore structures to rotate in mooring conditions. When external forces are applied to marine structures in places where the effects of waves, currents, wind, and well are severe and the sea conditions are poor, the marine structures can rotate about the turret naturally.

US Patent Publication No. US2010 / 0190393 (published Jul. 29, 2010) discloses an example of such a turret mooring system. This turret mooring system may allow offshore structures, such as FPSOs, to rotate about the turret, and allow offshore structures to move away from the mooring system when the offshore structure needs to be moved.

Patent Document 1: U.S. Published Patent Application No. 2010/1090393 (published on June 29, 2010)

An embodiment of the present invention is to provide a turret mooring system for offshore structures that can be mooring offshore structures in the work area, and can easily move the offshore structures after releasing the mooring if necessary.

In addition, an embodiment of the present invention is to provide a turret mooring system for offshore structures that can be easily installed regardless of the seabed terrain.

According to an aspect of the invention, the connection portion fixed in the water by the mooring line; A turret installed to rotate in the offshore structure and having a connection groove for receiving the connection portion at a lower portion thereof; And a turret mooring system for offshore structures may be provided that is installed in the connection groove and including a binding device for binding the connection portion entered into the connection groove.

The turret mooring system may further include a sealing device mounted to the connection groove and expanded by gas filling to seal between the outer surface of the connection portion and the inner surface of the connection groove.

The mooring line may include a plurality of tendon pipes which are vertically lowered from the connection part and whose lower end is fixed to the sea bottom by an anchor.

The connecting portion includes a binding groove formed along a circumference, wherein the binding device includes a binding rod capable of entering the binding groove, an operation device for advancing the binding rod for binding and releasing the binding rod, and installed in the binding rod. And it may include one or more rollers in contact with the inner surface of the binding groove.

The roller may include a side roller in contact with the inner side of the binding groove, an upper roller in contact with the upper surface of the binding groove, and a lower roller in contact with the bottom surface of the binding groove.

The sealing device may include a sealing tube installed in the connecting groove and a gas injection device for injecting gas into the sealing tube in a form in which the connection part surrounds the surroundings.

The turret mooring system may further include a drainage device for draining the water inside the connection groove after the closing operation of the closure device.

The turret mooring system may further include a positive pressure supply device for injecting gas into the connection groove after the sealing operation of the closure device to maintain the inside of the connection groove at a pressure higher than the water pressure of the corresponding position.

Turret mooring system for offshore structures according to an embodiment of the present invention can easily bind the offshore structure to the working area of the sea because it can be connected by connecting the connection groove and the connection of the turret after moving the offshore structure to the fixed side in the water It can be moored and offshore structures can be easily moved after release.

In addition, the turret mooring system for marine structures according to the present embodiment can seal the inner space of the connecting groove with a sealing device after binding the connecting portion and the turret, and can drain the water inside the connecting groove with a drainage device after sealing. The connection part can be kept dry.

In addition, the turret mooring system for offshore structures according to the present embodiment can supply the inert gas into the connection groove with a positive pressure supply device, so that the interior space of the connection groove can be maintained at a pressure higher than the water pressure at the corresponding position. Can be prevented from invading, and the risk factors due to sparks can be minimized.

In addition, the turret mooring system for marine structures according to the present embodiment can minimize the installation area for installing the anchor on the sea bottom because the mooring line for fixing the connecting portion is laid down a plurality of tendon pipe vertically. . Therefore, the joint can be easily installed regardless of the topography of the seabed.

1 illustrates a turret mooring system and an offshore structure moored by the turret mooring system according to an embodiment of the present invention.
2 is a cross-sectional view of a turret mooring system according to an embodiment of the present invention, showing a state in which the connection portion and the turret are connected.
3 is a cross-sectional view of the turret mooring system according to an embodiment of the present invention, showing a state in which the connection portion and the turret are separated.
4 is a detailed view of portion IV of FIG. 2.
5 is a cross-sectional view taken along the line VV of FIG. 2.
6 is a cross-sectional view of the anchor fixing the connection portion of the turret mooring system according to an embodiment of the present invention.
7 to 9 are shown step by step mooring and release of the marine structure by the turret mooring system according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 shows a turret mooring system 20 for offshore structures and an offshore structure 10 moored by the turret mooring system 20 according to an embodiment of the present invention. The offshore structure 10 can carry out work while moored at sea, such as floating production storage offloading (FPSO) or floating storage offloading (FSO), This may be a possible floating structure.

The turret mooring system 20 may moor the offshore structure 10 to a working position at sea, as shown in FIGS. 1 and 2. In addition, when an external force is applied to the marine structure 10 under the influence of waves, currents, wind, and the like, the marine structure 10 may be rotated in the mooring state. The turret mooring system 20 is a turret 30 rotatably installed in the offshore structure 10 in a form penetrating up and down the offshore structure 10, so that the turret 30 can be connected or separated from the turret 30 The connection part 40 installed in the water by the mooring line 50 is included.

2 and 3, the turret 30 may be provided as a cylindrical structure in which the internal space can be maintained in a waterproof state, and the turret installation hole 11 formed to penetrate up and down the marine structure 10. Is supported to rotate. To this end, a plurality of bearings 12a and 12b may be installed between the outer surface of the turret 30 and the inner surface of the turret installation hole 11. A flange portion 31 is provided at an upper portion of the turret 30, and a bearing 12c may be installed between the flange portion 31 and the offshore structure 10. The lower portion of the turret 30 is provided in the form of the outer diameter is extended to accommodate and support the connection portion 40, the connection portion coupling portion 32 having a connection groove 33 with its lower surface is provided in an integrated form. Can be. A plurality of bearings 12d and 12e may be installed between the connection part coupling part 32 and the marine structure 10 for smooth rotation.

The connection part 40 may be provided in a cylindrical shape that may be accommodated as the connection groove 33 of the turret 30. The connection part 40 may be provided by a steel structure including an empty space therein to maintain buoyancy or may be provided by a material that can float on water itself.

The connection unit 40 may be mounted and supported by a riser 60 connected to the seabed well. The riser 60 may be coupled to the connecting portion 40 in a form of penetrating the connecting portion 40 vertically so that the upper portion of the connecting portion 61 may be connected to the pipeline 65 installed in the turret 30. The connection part 40 may be exposed on the top. This is because when the connecting portion 40 is connected to the connecting groove 33 of the turret 30, the pipe connecting portion 61 of the riser 60 and the pipeline 65 of the turret 30 are connected to the continuous seabed resources (crude oil). , Natural gas, etc.). Although only one riser 60 is installed in the connecting portion 40 in the drawing, the plurality of risers may be connected to the connecting portion 40 in the same manner.

The mooring line 50 which fixes the connection part 40 in water is a plurality of tendons lowered vertically toward the sea bottom 1 in the state fixed to the lower surface of the connection part 40, as shown in FIGS. 1 and 6. A pipe 51 and an anchor 52 for fixing the lower end of each tendon pipe 51 to the bottom surface 1 may be included.

As shown in FIG. 6, the anchor 52 includes a cylindrical body 52a with a closed upper portion, and a pumping device 52b installed at an upper portion of the body 52a to form a negative pressure in an inner space of the body 52a. It may be a conventional suction anchor. The anchor 52 is to drop the body 52a to the bottom surface 1 so that the pumping device 52b to form a negative pressure inside the body 52a so that the body 52a is embedded in the seabed to be fixed can do. Here, as an example, the suction anchor is provided, but the tendon pipe 51 may be fixed to the bottom of the bottom surface 1, so the shape of the anchor is not limited thereto.

As shown in FIG. 1, the mooring line 50 has a lower end of the tendon pipe 51 fixed by an anchor 52 and an upper end of the tendon pipe 51 coupled with the connection part 40 so that the connection part 40 is provided. Since the state of being pulled upward by buoyancy of the connection portion 40 can be fixed in a stable state in the water. In particular, the mooring line 50 is a method of laying down the plurality of tendon pipe 51 vertically from the connecting portion 40 can minimize the installation area for installing the anchor 52 on the sea bottom (1). Therefore, the connecting portion 40 can be easily installed regardless of the topography of the seabed.

That is, since the conventional mooring line of a tree type is a method of fixing a plurality of steel wires in a tree shape and fixing it on the sea bottom, it may be difficult to install when the occupancy of the sea bottom area is relatively large and the sea bottom shape is irregular. However, since the mooring line 50 of the present embodiment can minimize the seabed installation area, the mooring line 50 can be easily installed regardless of the seabed topography.

Referring to FIGS. 2 and 3 again, the turret mooring system 20 according to the present exemplary embodiment may bind the connecting portion 40 while the connecting portion 40 enters the connecting groove 33 of the turret 30. A coupling groove 41 formed in the connecting portion 40 and a plurality of coupling devices 70 coupled thereto are provided. In addition, the sealing device 80, which seals the gap between the outer surface of the connecting portion 40 and the inner surface of the connecting groove 33 and blocks the ingress of seawater into the connecting groove 33, the water in the sealed inner space of the connecting groove 33 It includes a positive pressure supply device 100 for injecting gas into the drainage device 90 for draining, the interior of the sealed connection groove 33 to maintain the inside of the connection groove 33 at a pressure higher than the water pressure of the corresponding position.

3 and 4, the binding groove 41 may be formed along the upper circumference of the connecting portion 40. The binding device 70 is a binding rod 71 that can enter the binding groove 41 of the connecting portion 40, and is fixed to an inner surface side of the connecting groove 33 for binding and releasing the binding rod 71. It may include an operating device 72 for advancing and retreating in the direction of the binding groove 41, rollers (73a, 73b, 73c) provided in the binding rod 71 to contact the inner surface of the binding groove (41). And, as shown in FIG. 5, a plurality of such binding devices 70 may be disposed radially around the connection part 40 for stable binding of the connection part 40.

The operating device 72 for advancing and restraining the binding rod 71 may be constituted by a hydraulic cylinder or a transmission device employing a rack and a pinion gear. As shown in FIG. 4, the rollers have a side roller 73a in contact with the inner side of the binding groove 41, an upper roller 73b in contact with the upper surface of the binding groove 71, and a lower surface of the binding groove 41. It may include a lower roller (73c) in contact. Here, an example in which three rollers are installed on the binding rod 71 so that the connecting portion 40 can rotate smoothly in a state where the connecting portion 40 is bound to the lower portion of the turret 30 is illustrated, but the installation form of the rollers is not limited thereto.

As shown in FIGS. 2 and 4, the sealing device 80 may be installed between the inner surface of the connection groove 33 and the outer surface of the connection portion 40 in the lower portion of the binding device 70. The sealing device 80 has an annular sealing tube 81 provided on the inner surface side of the connecting groove 33 in the form of surrounding the connecting portion 40 entering the connecting groove 33 and the expansion of the sealing tube 81. The gas injection device 82 for injecting gas into the hermetic tube 81 may be included. The sealing tube 81 may be provided by an elastic material that has a space for accommodating the compressed gas therein and is elastic. The gas injection device 82 may include a gas pump 82a installed inside the turret 30 and a pipe 82b for supplying compressed gas from the gas pump 82a to the hermetic tube 81. In addition, the gas pump 82a may include a discharge valve for discharging the gas of the closed tube 81 although not shown in the drawing.

The sealing device 80 is the connection portion 40 enters into the connection groove 33 of the turret 30 and is bound, and then the gas injection device 82 supplies the gas to the sealing tube 81 to seal the tube 81 ) Can be expanded. When the sealing tube 81 is expanded, the sealing tube 81 is in close contact with the outer surface of the connecting portion 40, the inner space of the connection groove 33 on the upper side of the sealing tube 81 can be maintained in a sealed state.

As shown in FIG. 2, the drainage device 90 includes a drain pump 91 installed inside the turret 30 and a suction pipe 92 extending from the suction side of the drain pump 91 to the inner space of the connection groove 33. ) And a drain pipe 93 extending outward from the discharge side of the drain pump 91 to the outside through the turret 30. The drainage device 90 may discharge the water present in the connection groove 33 to the outside by operating the drainage pump 91 in a state in which the connection groove 33 is sealed by the sealing device 80. .

The positive pressure supply device 100 may include a compressed gas pump 101 installed in the turret 30, and a gas supply pipe 102 extending into the connection groove 33 from the discharge side of the compressed gas pump 101. . The positive pressure supply device 100 injects compressed gas into the connection groove 33 after performing the above-described sealing operation and drainage operation to maintain the inside of the connection groove 33 at a pressure higher than the water pressure at the corresponding position. 33) It can more reliably prevent the inflow of seawater. In this case, the gas supplied to the connection groove 33 by the positive pressure supply device 100 may be an inert gas such as nitrogen. When inert gas is injected into the connection groove 33 as described above, even when the connection portion 40 rotates relative to the connection groove 33, a risk factor such as spark can be minimized.

The following describes a method of mooring or releasing mooring offshore structures using the turret mooring system according to the present embodiment.

As shown in FIG. 1, the connecting portion 40 maintains a fixed state in the water of the working area. When the marine structure 10 is moored to the connecting portion 40, first, as shown in FIG. 7, the offshore structure 10 is positioned such that the connecting groove 33 of the turret 30 is positioned above the connecting portion 40. Move to align. In this state, as shown in FIG. 8, by increasing the draft of the offshore structure 10, the offshore structure 10 is allowed to sink so that the connecting portion 40 enters the connecting groove 33 of the turret 30. do. At this time, the draft can be adjusted by filling the ballast water in the ballast tank of the offshore structure 10.

After the connecting portion 40 enters the connecting groove 33 of the turret 30, as shown in FIG. 2, the binding device 70 is operated to allow the connecting portion 40 to be engaged in the connecting groove 33. . 4 and 5, each of the plurality of binding devices 70 enters the binding groove 41 of the connecting portion 40 and binds the connecting portion 40. In this case, since the rollers 73a, 73b, and 73c installed on the binding rod 71 are in contact with the inner surface of the binding groove 41, the connection portion 40 is bound so as not to be separated from the turret 30, but the turret for the connection portion 40 is provided. Allow relative rotation of to some degree.

After the binding operation, as shown in FIGS. 2 and 4, the sealing device 80 is operated to seal the space between the lower outer surface of the connecting portion 40 and the inner surface of the connecting groove 33. At this time, when gas is injected from the gas pump 82 into the hermetic tube 81, the hermetic tube 81 expands and is in close contact with the outer surface of the connection part 40.

After the closing operation, the drainage device 90 is operated to discharge water existing in the inner space of the connection groove 33 above the sealing device 80 to the outside. Therefore, the internal space of the connection groove 33 can be maintained in a dry state. Then, the positive pressure supply device 100 is operated to inject an inert gas into the connection groove 33 to maintain the inside of the connection groove 33 at a pressure higher than the water pressure at the corresponding position. If the inside of the connection groove 33 is maintained at a positive pressure in this way, it is possible to prevent the phenomenon of seawater intrusion into the connection groove 33. In addition, since the inert gas such as nitrogen is filled in the connection groove 33, the risk of sparks due to the relative rotation of the connection part 40 in the connection groove 33 can be minimized.

As such, the turret mooring system 20 according to the present embodiment can be easily connected to the turret 30 of the offshore structure 10 by the connection part 40 fixed in the water, and after the binding, the interior of the connection groove 33. Can be kept waterproof. In addition, after the connection to allow the relative rotation of the turret relative to the connection portion 40 to some extent to prevent the excessive force applied to the connection portion can minimize the failure of the connection portion.

On the other hand, where there is a floating iceberg like the polar region, the marine structure 10 may be pushed by the floating iceberg. As such, when the surrounding conditions are not enough or the weather conditions are poor, it is difficult for the offshore structure 10 to continue working in the work area, or when the offshore structure 10 needs to be moved to another adjacent work area, the connection part 40 is used. By separating the turret 30 from the offshore structure 10 can be moved.

In this case, as shown in FIG. 9, the binding of the binding device 70 is released, the sealing of the sealing device 80 is released, and the draft of the marine structure 10 is reduced so that the marine structure 10 rises. . That is, the offshore structure 10 is raised in such a manner as to discharge the ballast water filled in the ballast tank of the offshore structure 10 so that the connecting portion 40 is separated from the access groove 33 of the turret. The offshore structure 10 may move to an adjacent work area or refuge in this state.

10: offshore structure, 20: turret mooring system,
30: turret, 33: groove,
40: connection part, 41: binding,
50: mooring line, 51: tendon pipe,
52: anchor, 60: riser,
70: binding device, 80: sealing device,
90: drainage, 100: positive pressure supply.

Claims (8)

A connection part fixed in water by a mooring line;
A turret installed to rotate in the offshore structure and having a connection groove for receiving the connection portion at a lower portion thereof; And
A coupling device installed in the connection groove and for binding the connection portion entered into the connection groove;
The connecting portion includes a binding groove formed along the circumference,
The binding device includes a binding rod capable of entering the binding groove, an operation device for advancing the binding rod for binding and release, and one or more rollers installed on the binding rod and in contact with an inner surface of the binding groove. Turret mooring system for offshore structures. The method of claim 1,
Turret mooring system for offshore structures further comprises a sealing device mounted to the connecting groove and expanded by gas filling to seal between the outer surface of the connecting portion and the inner surface of the connecting groove. The method of claim 1,
The mooring line is vertically descended from the connecting portion and a turret mooring system for offshore structures comprising a plurality of tendon pipes, the lower end of which is fixed to the sea bottom by an anchor. delete The method of claim 1,
The roller
A side roller in contact with the inner side of the binding groove,
An upper roller in contact with the upper surface of the binding groove;
Turret mooring system for offshore structures comprising a lower roller in contact with the lower surface of the binding groove. 3. The method of claim 2,
The closure device
A hermetically sealed tube installed in the connecting groove in a form in which the connecting portion surrounds a circumference;
Turret mooring system for offshore structures comprising a gas injection device for injecting gas into the hermetic tube. 7. The method according to claim 2 or 6,
Turret mooring system for a marine structure further comprising a drainage for draining the water in the connection groove after the sealing operation of the closure device. 7. The method according to claim 2 or 6,
And a positive pressure supply device for injecting gas into the connection groove after the sealing operation of the sealing device to maintain the inside of the connection groove at a pressure higher than the water pressure at the corresponding position.

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