JP2016032948A - Floating body structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a floating body structure capable of suppressing fluctuation and breakage due to collision of a floating body such as floating ice.SOLUTION: A floating body structure includes: a cylindrical turret part 10 connected with mooring ropes 40-1, 40-2 fixed to the sea bottom; and a hollow cylindrical or hollow polygonally columnar floating body part 20 rotating around a lateral wall of the turret part 10. Therein, the floating part 20 includes a polygonal first surface 21 which is disposed on the side of the sea bottom and has an outer circumference of circular shape or polygon having n summits (where n is an integer of 5 or more), a second surface 22 which is disposed in parallel to the first surface and has an outer circumferential shape equal to that of the first surface, a lateral wall part 23 which connects an outer circumferential part of the first surface and an outer circumferential part of the second surface and a turret storage part 24 which penetrates center parts of the first surface and the second surface and stores the turret part 10.SELECTED DRAWING: Figure 1

Description

  TECHNICAL FIELD The present invention relates to a floating structure that is installed on the sea and is equipped with equipment for developing resources such as drilling and production of oil and natural gas.

  Conventionally, a ship-shaped floating structure provided with a turret connected to a mooring line fixed to the seabed is known. In the conventional floating structure, when external forces such as waves, ocean currents, and winds are applied to the floating structure, the swinging of the floating structure can be suppressed by turning the ship-shaped floating structure with respect to the turret. (For example, see Patent Document 1).

  A floating structure having a bowl-shaped cross section that can rotate with respect to a cylindrical body connected to a mooring line fixed to the seabed is also known. In the floating structure, the impact caused by the collision of drift ice can be reduced by rotating the floating structure according to the external force generated when the drifting ice floating in the ice sea collides (see, for example, Patent Document 2). .

JP-A-11-321780 JP 58-180394 A

  In a conventional ship-shaped floating structure, swinging of the floating structure can be suppressed by directing the bow in the direction in which external forces such as waves, ocean currents, and winds are applied. However, when the directions of forces received from waves, ocean currents, and winds are different from each other, any external force may be applied to the side surface of the floating structure. For example, when the direction of the bow is determined in consideration of the ocean current and the wind, if a wave is received from the side of the hull, the floating structure becomes unstable and swings greatly.

A floating structure with a bowl-shaped cross section does not have directionality unlike a ship shape, so it does not become extremely unstable even if it receives external force from the side, and the problem that the floating structure swings greatly is Hard to occur. However, when a bowl-shaped floating structure is used in the ice sea, drifting drift ice tends to enter the lower part of the floating structure. As a result, there has been a problem that the riser tube or the mooring line is likely to be damaged by the collision of the drift ice with the riser pipe or the mooring line provided at the lower part of the floating structure.
In addition, although there is no serious instability such as overturning, once the shaking starts, there is a problem that the shaking is difficult to attenuate because there is little resistance of seawater under the waterline.

  Therefore, the present invention has been made in view of these points, and provides a floating structure that is stable even under severe sea conditions such as the ice sea and that can suppress the swing and breakage caused by the collision of floating objects such as drift ice. The purpose is to do.

  In the first aspect of the present invention, a cylindrical turret portion connected to a mooring line fixed to the seabed, and a hollow columnar or hollow polygonal floating body portion rotating around a side wall of the turret portion The floating body portion is provided on the seabed side, and has a circular outer periphery or a polygonal first surface having n vertices (where n is an integer of 5 or more), and parallel to the first surface. The provided second surface having the same outer periphery as the first surface, a side wall portion connecting the outer peripheral portion of the first surface and the outer peripheral portion of the second surface, and the central portions of the first surface and the second surface And a turret housing part that houses the turret part.

  Said turret part may have the mooring line connection part which connects the mooring line provided in the position near the seabed rather than the 1st surface of a floating body part. Further, the turret part has a plate-like mooring line protection part protruding from a portion penetrating the floating body part at a position closer to the sea floor than the first surface, and the mooring line is provided on the sea bed of the mooring line protection part. It may be provided on the near surface.

  Said floating-body part may further have the protrusion part provided in the position nearer to the seabed than a waterline. In addition, the floating body portion may further include a rotation propulsion portion that generates a propulsion force that rotates with respect to the turret portion. Furthermore, the floating body portion may further include a protrusion portion formed in an oblique direction on the side wall portion.

  The floating body portion may include a storage portion that stores a liquid and a plurality of partition walls that divide the storage portion into a plurality of regions. The floating body portion may include a plurality of floating blocks having the same shape.

  According to the present invention, there is an effect that it is possible to suppress rocking and breakage due to a collision of a suspended matter such as drift ice.

It is sectional drawing of the floating body structure which concerns on 1st Embodiment. It is sectional drawing in the water line of a floating body part in case a floating body part is cylindrical shape. It is sectional drawing in the waterline of a floating body part in case a floating body part is octagonal prism shape. It is sectional drawing of the floating body structure which concerns on 2nd Embodiment. It is a side view of the floating part which concerns on 3rd Embodiment. It is sectional drawing in the water line of the floating body structure which concerns on 4th Embodiment. It is a figure which shows the other example of sectional drawing in the water line of the floating body structure which concerns on 4th Embodiment. It is a figure which shows the relationship between the collision direction of ice, and the direction which rotates a floating body part. It is a figure which shows an example of a floating body block. It is sectional drawing of the floating body structure which concerns on 7th Embodiment.

<First Embodiment>
FIG. 1 is a cross-sectional view of a floating structure 100 according to the first embodiment. The floating body structure 100 includes a turret portion 10 and a floating body portion 20. The floating structure 100 is provided with a riser pipe 50 that penetrates the turret portion 10 and pumps oil from the seabed. The floating body 20 is provided with an equipment storage section 60 having a tower for storing equipment for producing oil.

  The turret portion 10 is connected to mooring lines 40-1 and 40-2 (hereinafter, referred to as mooring lines 40) having one end fixed to the seabed and the other end connected to the turret unit 10, and rotated with respect to the floating body 20 This is a cylindrical object. The floating body 20 is a hollow cylindrical or hollow polygonal object that rotates around the side wall of the turret 10. Since the floating body portion 20 has a columnar shape or a polygonal column shape, fragments of the drift ice a that collide with the floating body portion 20 are less likely to enter the lower portion of the floating body portion 20 as compared with the case where the floating body portion 20 has a bowl shape.

  The floating body portion 20 includes a first surface 21, a second surface 22, a side wall portion 23, and a turret housing portion 24. The first surface 21 is a polygonal surface having a circular outer periphery or n (where n is an integer of 5 or more) vertices provided on the seabed side. The second surface 22 is a surface that is provided in parallel with the first surface 21 and has an outer periphery that has the same shape as the first surface 21. The side wall portion 23 is a side surface that connects the outer peripheral portion of the first surface 21 and the outer peripheral portion of the second surface 22. A circular hollow portion through which the turret portion 10 penetrates is formed in the central portion of the first surface 21 and the second surface 22, and the floating body portion 20 has a donut shape.

  When the outer circumferences of the first surface 21 and the second surface 22 are polygonal, all apex angles are more than 90 ° in order to relieve the stress applied in the direction perpendicular to the side wall 23 when the ice floe a collides. Is also preferably a large polygon. Therefore, the first surface 21 and the second surface 22 are preferably regular polygons having five or more vertices. That is, when the first surface 21 and the second surface 22 are polygons having n vertices (n is an integer of 5 or more), n is preferably as large as possible, and the first surface 21 and the second surface 22 are circular. More preferably.

  The turret accommodating portion 24 is a cylindrical hollow portion that penetrates the central portions of the first surface 21 and the second surface 22 and accommodates the turret portion 10. In the turret housing part 24, a plurality of bearings 25 are provided between the turret part 10 and the floating body part 20. By providing a plurality of bearings 25 between the turret part 10 and the floating body part 20, when the ice floe a collides with the floating body part 20 and stress is applied, the floating body part 20 is in contact with the turret part 10. Since it can rotate freely, the stress applied to the floating body 20 can be relaxed.

The turret part 10 has a plate-shaped mooring line protection part 11 and a locking part 12 that protrude in the horizontal direction from the cylindrical part at both ends of the cylindrical part that penetrates the floating body part 20.
The mooring line protection unit 11 is provided at a position closer to the seabed than the first surface 21. On the surface of the mooring line protection unit 11 near the sea floor, a plurality of mooring line connection parts 13-1 and 13-2 (hereinafter referred to as mooring line connection parts 13) for connecting the mooring line 40 are provided. Yes. One end of the plurality of mooring lines 40 is connected to one of the plurality of mooring line connecting portions 13 and the other end is fixed to the seabed.

  The locking portion 12 is provided at a position farther from the seabed than the second surface 22. A plurality of bearings 26 are provided between the locking portion 12 and the second surface 22 of the floating body portion 20, and the locking portion 12 freely rotates on the second surface 22.

  The outer peripheral surface of the mooring line protection part 11 is provided outside the outer periphery of the cylindrical part of the turret part 10 and inside the side wall part 23. By making the diameter of the mooring line protection part 11 larger than the diameter of the cylindrical shape of the turret part 10, the distance between the outer peripheral surface of the mooring line protection part 11 and the mooring line connection part 13 can be increased. Even when the ice enters the vicinity of the mooring line protection unit 11, it is possible to prevent the drift ice a from colliding with the mooring line 40 connected to the mooring line connection unit 13.

  FIG. 2A is a cross-sectional view of the floating body 20 at the draft line when the floating body 20 has a cylindrical shape. When the floating body 20 has a cylindrical shape, the probability that the direction of the stress applied to the floating body 20 when the ice floe a collides with the side wall 23 matches the direction orthogonal to the side wall 23 is small. When the direction of the stress caused by the ice floe a does not coincide with the direction orthogonal to the side wall 23, a part of the stress is converted into a force that rotates the floating body 20, so The applied stress can be relaxed. Therefore, when the floating body 20 has a polygonal column shape or a cylindrical shape, the swinging or breaking of the floating body 20 due to a collision can be prevented, and the force applied to the mooring line 40 can be reduced.

  FIG. 2B is a cross-sectional view of the floating body 20 along the water line when the floating body 20 has an octagonal prism shape. Also in the floating body portion 20 shown in FIG. 2B, the size of the parallel surface of the side wall portion 23 is smaller than the size of the side surface of a general ship, so the drift ice a collides in a direction orthogonal to the side wall portion 23. Probability is small compared to ships. When the drift ice a collides in a direction other than the direction orthogonal to the side wall part 23, a part of the stress is converted into a force for rotating the floating body part 20, so that the stress can be relaxed.

As described above, according to the floating structure 100 according to the first embodiment, since the floating body portion 20 has a polygonal column shape or a columnar shape, fragments of the drift ice a generated when the ice floe a collides with the floating body portion. It is difficult to enter under 20. Further, since the floating body 20 has a polygonal column shape or a cylindrical shape, a part of the stress when the ice floe a collides can be converted into a force for rotating the floating ice part 20, so the ice floe a collides. The force in the direction perpendicular to the side wall portion 23 that occurs in the case can be reduced.
Moreover, since the resistance by the side wall part 23 and the 1st surface 21 arises at the time of a fluctuation | variation, a fluctuation | variation is easy to attenuate | dampen and, as a result, it becomes easy to make a fluctuation smaller than a bowl type.

  Even if a force that rotates the floating body 20 is generated by the collision of the drift ice a, the bearing 25 and the bearing 26 are provided between the turret 10 and the floating body 20, so that the turret 10 and the floating body 20 The turret 10 does not rotate because the friction between the two is sufficiently small. Therefore, it is possible to suppress the force in the direction orthogonal to the side wall portion 23 and the force in the rotation direction, which are applied to the mooring line 40 connected to the turret portion 10. As a result, the floating structure 100 according to the present embodiment can prevent the turret unit 10 and the floating unit 20 from moving, swinging, or breaking.

<Second Embodiment>
FIG. 3 is a cross-sectional view of the floating structure 100 according to the second embodiment. The floating structure 100 shown in FIG. 3 differs from the floating structure 100 shown in FIG. 1 in that the floating body 20 further includes a protrusion 27 provided at a position closer to the sea floor than the water line. Is the same. Since the floating body 20 has the projecting portion 27, it is difficult for fragments of the ice floe a that have collided to sink below the waterline, so that the pieces of ice floe a can be prevented from colliding with the mooring line 40 and at the time of shaking. Due to the resistance from seawater generated by the protrusions, it is possible to obtain even greater vibration damping performance.

  As an example, the outer periphery of the protrusion 27 is a circle larger than the diameter of the floating body 20. When the floating body portion 20 has a polygonal column shape, the outer periphery of the protruding portion 27 has a polygonal shape in which each side is longer than the polygon on the outer periphery of the floating body portion 20.

  The restitution coefficient of the protruding portion 27 is preferably smaller than the restitution coefficient of the side wall portion 23. That is, it is preferable that the protrusion 27 is softer than the side wall 23, unlike the formation material of the side wall 23. Since the drift ice a collides with the projection 27 before colliding with the side wall 23, when the projection 27 has flexibility, the impact when the drift ice a collides with the floating body 20 is absorbed by the projection 27. Is done. As a result, even if the drift ice a reaches the side wall 23, the impact applied to the floating body 20 is reduced.

<Third Embodiment>
FIG. 4 is a side view of the floating body 20 according to the third embodiment. The floating body portion 20 shown in FIG. 4 is different from the floating body portion 20 shown in FIG. 1 in that the floating body portion 20 further includes a protruding portion 28 formed on the side wall portion 23 in an oblique direction. For example, the protruding portion 28 is formed in a spiral shape along the side wall portion 23.

  When seawater flows around the cylindrical floating body 20, Karman vortices are generated on the downstream side of the floating body 20. Since Karman vortices are alternately generated on the left and right of the floating body 20, the floating body 20 vibrates due to the generation of the Karman vortex, the equipment housing 60 provided on the floating body 20 swings, and the mooring line 40. Stress. Since the floating body 20 has the protrusions 28, the positions where Karman vortices are generated around the floating body 20 can be randomly distributed, so that the swinging of the floating body 20 due to the generation of vortices can be suppressed. . As a result, according to the floating body 20 according to the present embodiment, it is possible to prevent the production facility from swinging and reduce the stress applied to the mooring line 40.

<Fourth Embodiment>
FIG. 5 is a cross-sectional view of the floating structure 100 according to the fourth embodiment at the water line. In the floating body 20 shown in FIG. 5, an accommodating portion for accommodating a liquid such as ballast water and oil is formed in a space inside the side wall portion 23. The floating body portion 20 shown in FIG. 5 is different from the floating body portion 20 shown in FIG. 1 in that it has a plurality of partition walls 29 that divide the storage portion of the floating body portion 20 into a plurality of storage chambers 30. It is.

  The plurality of partition walls 29 are provided, for example, in a direction connecting the center point of the floating body portion 20 and the side wall portion 23. It is preferable that an even number of the plurality of partition walls 29 is provided at equal intervals. When the floating body 20 has an even number of partition walls 29, the storage chamber 30 having the same shape is provided at a point-symmetrical position with respect to the center point of the floating body 20. Therefore, the floating body 20 can be kept horizontal by putting the same weight of liquid into the plurality of storage chambers 30 provided at point-symmetric positions.

  The floating body 20 shown in FIG. 5 further includes a separation wall 33 that divides each storage chamber into a plurality of regions. Each of the storage chambers 30 is divided by a separation wall 33 into a first storage chamber 31 that stores ballast water and a second storage chamber 32 that stores the produced oil.

  FIG. 6 is a diagram illustrating another example of a cross-sectional view of the floating structure 100 according to the fourth embodiment along the waterline. The floating body 20 shown in FIG. 6 does not have the separation wall 33 instead of having more partition walls 29 than the floating body 20 shown in FIG. The floating body 20 shown in FIG. 6 has eight accommodating chambers 30 by eight partition walls 29. The floating body unit 20 can sequentially store ballast water and oil in the plurality of storage chambers 30. For example, by storing oil in the storage chambers 30 adjacent to both sides of the storage chamber 30 that stores the ballast water, the floating body 20 can store the oil while maintaining the horizontal balance.

  As described above, according to the floating structure 100 according to the fourth embodiment, ballast water and oil can be stored in the plurality of storage chambers 30 formed by the partition walls 29 provided inside the floating body portion 20. Therefore, the produced oil can be accommodated while maintaining the horizontal balance of the floating body 20.

<Fifth Embodiment>
[The floating body 20 has a rotation propulsion unit]
In the above-described embodiment, a configuration has been described in which the floating body 20 is rotated by an impact when the ice floe a collides, thereby relieving the stress caused by the collision. In order to further reduce the impact when the ice floe a collides, the floating structure 100 may further include a rotation propulsion unit that rotates the floating unit 20. The rotation propulsion unit is, for example, a plurality of thrusters provided on the first surface 21. Each thruster has a screw, for example. The plurality of thrusters are preferably provided on the first surface 21 at equal intervals.

Specifically, when the floating structure 100 detects that the drift ice a has collided, the floating structure 20 rotates the floating body portion 20 in a direction to relieve stress caused by the collision of the drift ice a.
FIG. 7 is a diagram illustrating the relationship between the collision direction of the drift ice a and the direction in which the floating body 20 is rotated. The rotation propulsion unit rotates the floating body 20 in the same direction as the direction in which the drift ice a collides with the direction connecting the drift ice a and the center point of the floating structure 100. For example, the floating body 20 includes an acceleration sensor that detects the acceleration of the floating body 20 and detects the rotation direction of the floating body 20 caused by the collision of the drift ice a. The rotation propulsion unit further rotates the floating body 20 in the rotation direction of the floating body 20 caused by the collision of the drift ice a.

  The floating structure 100 may include an image sensor that detects the moving direction of the drifting ice a. The rotation propulsion unit detects the direction in which the drift ice a approaches the floating body 20 based on the moving direction of the drift ice a detected by the image sensor, and determines the direction in which the floating body 20 is rotated based on the detected direction. May be. The rotation propulsion unit may control the speed at which the floating body unit 20 is rotated based on the size of the drift ice a detected by the image sensor. For example, the rotation propulsion unit increases the rotation speed as the drift ice a increases.

  As described above, the floating body structure 100 includes the rotation propulsion unit, and the floating body portion 20 is rotated according to the moving direction or size of the floating body such as the drift ice a, thereby being orthogonal to the side wall portion 23 due to the collision of the drift ice a. The stress generated in the direction can be further relaxed.

<Sixth Embodiment>
[The floating body 20 is composed of a plurality of blocks]
In the above embodiment, the floating body 20 has an integral structure. On the other hand, the floating body 20 may be configured by a plurality of floating blocks 70.
FIG. 8 is a diagram illustrating an example of the floating body block 70. The floating block 70 shown in FIG. 8 is a fan-shaped bottom body having a fan-shaped bottom surface. The plurality of floating body blocks 70 are joined to each other so as to surround the turret portion 10, and constitute the floating body portion 20.

Hereinafter, a method for manufacturing the floating structure 100 using the plurality of floating blocks 70 will be described.
First, the turret part 10 is assembled, and the bearing 25 is attached to the side surface of the turret part 10. Next, a plurality of floating blocks 70 are sequentially arranged outside the bearing 25. Subsequently, adjacent floating body blocks 70 are joined to each other. By assembling the floating structure 100 according to the above procedure, the turret unit 10 and the plurality of floating blocks 70 are assembled at the dock even when the floating body 20 has a size that does not fit in the dock for manufacturing the ship. Later, the floating structure 100 can be manufactured by joining a plurality of floating blocks 70 outside the dock.

<Seventh Embodiment>
[Providing production equipment on the turret 10]
FIG. 9 is a cross-sectional view of a floating structure 100 according to the seventh embodiment. In the above embodiment, the facility accommodating portion 60 is provided on the floating body portion 20. On the other hand, in the floating structure 100 according to the present embodiment, the equipment housing portion 60 is provided on the locking portion 12 of the turret portion 10. In the turret part 10 shown in FIG. 9, the area of the locking part 12 that covers the second surface 22 of the floating body part 20 is larger than the area of the locking part 12 shown in FIG. Specifically, the engaging portion 12 has a circular shape having a diameter that is substantially the same as the diameter of the floating body portion 20 and smaller than the diameter of the floating body portion 20.

  As described above, the floating structure 100 according to the present embodiment can secure a sufficient region for providing the equipment accommodating unit 60 on the turret unit 10. Furthermore, according to the floating structure 100 according to the present embodiment, since the equipment accommodating portion 60 is provided on the turret portion 10 fixed to the sea floor by the mooring line 40, the drift ice a collides. Even if it exists, the equipment accommodating part 60 does not rotate. Therefore, according to the floating structure 100 according to the present embodiment, it is possible to suppress the swing applied to the production facility accommodated in the facility accommodating portion 60.

  As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. It will be apparent to those skilled in the art that various modifications or improvements can be added to the above-described embodiment. It is apparent from the scope of the claims that the embodiments added with such changes or improvements can be included in the technical scope of the present invention.

DESCRIPTION OF SYMBOLS 10 ... Turret part, 11 ... Mooring line protection part, 12 ... Locking part, 13 ... Mooring line connection part, 20 ... Floating body part, 21 ... 1st surface, 22. ··· Second surface, 23 ··· side wall portion, 24 ··· turret housing portion, 25 ··· bearing, 26 ··· bearing, 27 ··· projection, 28 ··· projection, 29 ··· · Partition wall, 30 ··· storage chamber, 31 ··· first storage chamber, 32 ··· second storage chamber, 33 ··· separation wall, 40 · · mooring line, 50 · · · riser pipe ... Equipment housing part, 70 ... Floating body block, 100 ... Floating structure

Claims (8)

A cylindrical turret connected to a mooring line fixed to the seabed;
A hollow cylindrical or hollow polygonal column floating body that rotates around the side wall of the turret,
The floating body is
A polygonal first surface provided on the seabed side, having a circular outer periphery or n vertices (where n is an integer of 5 or more);
A second surface provided parallel to the first surface and having an outer periphery having a shape equivalent to the first surface;
A side wall connecting the outer periphery of the first surface and the outer periphery of the second surface;
A floating structure having a turret housing portion that penetrates through a central portion of the first surface and the second surface and houses the turret portion.   2. The floating structure according to claim 1, wherein the turret portion includes a mooring line connection portion that is provided at a position closer to the sea floor than the first surface and connects the mooring line.   The turret part has a plate-like mooring line protection part protruding from a portion penetrating the floating body part at a position closer to the sea floor than the first surface, and the mooring line is a part of the mooring line protection part. The floating structure according to claim 2, wherein the floating structure is provided on a surface close to the seabed.   The said floating body part is a floating body structure as described in any one of Claim 1 to 3 which further has the protrusion part provided in the position near the said seabed rather than a water line.   The floating body structure according to any one of claims 1 to 4, wherein the floating body portion further includes a rotation propulsion unit that generates a propulsion force that rotates with respect to the turret unit.   The floating body structure according to any one of claims 1 to 5, wherein the floating body portion further includes a protruding portion formed in an oblique direction on the side wall portion. The floating body is
A storage section for storing liquid;
The floating structure according to any one of claims 1 to 6, further comprising: a plurality of partition walls that divide the housing portion into a plurality of regions.   The floating body structure according to any one of claims 1 to 7, wherein the floating body portion includes a plurality of floating blocks having the same shape.

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