JP6973732B2 - Riser tube support structure - Google Patents

Description

The present invention relates to a riser tube support structure for an offshore floating structure such as a floating production storage and shipping facility (FPSO) and a floating storage and shipping facility (FSO).

In the offshore floating structure, a large number of riser pipes connecting the seabed and the floating structure are provided, and fluids such as crude oil, gas, and seawater are transported through the riser pipes. The riser tube is flexible and is pulled in through a guide provided on the shipside skin near the keel, for example configured as a steel structure integrated with the shipside skin of the floating structure and projecting outward from the shipside skin. It is supported by a riser tube support structure (see Patent Document 1).

JP-A-2017-52469

However, the load due to the riser pipe and the module installed on the upper part of the riser pipe has been increasing in recent years, and in the riser pipe support structure of the structure that projects outward from the outer panel on the ship side, stress is concentrated in a part of the mounting part. Very high stress is generated.

An object of the present invention is to provide a riser tube support structure that can withstand a large load.

The riser pipe support structure of the present invention is a riser pipe support structure for holding and fixing a large number of riser pipes to the ship's side outer plate along the longitudinal direction of the offshore floating structure, and the riser pipe to be inserted is inserted. A riser tube fixing tube for holding and fixing, a fixing tube support structure for supporting the riser tube fixing tube, a bracket member for supporting the fixing tube support structure, and a predetermined along the longitudinal direction inside the ship side outer plate. It is provided with a side transformer provided at intervals and a reinforcing member provided parallel to the side transformer between the side transformers inside the ship side outer plate to support the fixed tube support structure, and the bracket member is along the side transformer. It is characterized by being attached to the outside of the outer panel on the ship side.

The reinforcing member is, for example, an intermediate frame provided in parallel with the side transformer, and the bracket member is attached to the outside of the ship side outer plate along the intermediate frame. The riser tube support structure comprises, for example, a web member connecting between the riser tube fixing tube and the ship side skin, and the web member is attached to, for example, the ship side skin along the reinforcing member. Inside the shipside skin, the reinforcing members extend only in a partial vertical range of the shipside skin from higher to lower than, for example, the bracket or web member attached to the shipside skin. do. The position where the top plate of the fixed tube support structure is attached to the ship-side outer plate corresponds to, for example, the height of the stringer provided inside the ship-side outer plate.

The dimensions of each member along the longitudinal direction of the fixed tube support structure are constant. A fixed tube support structure having a predetermined length capable of supporting a predetermined number of riser tube fixing tubes is configured as a unit, and a plurality of units connected in the longitudinal direction can be attached to an offshore floating structure as a unit. Further, the fixed tube support structure portion may support the riser tubes in two rows in the width direction.

The offshore floating structure of the present invention is characterized by having the riser tube support structure according to any one of the above.

According to the present invention, it is possible to provide a riser tube support structure that can withstand a large load.

It is a perspective view from above which shows the structure of the riser tube support structure of 1st Embodiment of this invention. It is a partial cross-sectional view which shows the structure of the riser tube support structure of FIG. It is a partial plan view of the upper riser tube support structure constituting the riser tube support structure of FIG. It is a partial cross-sectional view at the position of the intermediate frame (reinforcing member) of FIG. It is a partial plan view of the lower riser tube support structure constituting the riser tube support structure of FIG. It is a partial plan view of the upper riser tube support structure which constitutes the riser tube support structure of the modification. It is a partial plan view which shows the structure of the riser tube support structure of 2nd Embodiment. It is a partial cross-sectional view which shows the structure of the riser tube support structure of FIG.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a perspective view from above of the ship side portion of the offshore floating structure 10 showing the configuration of the riser tube support structure according to the first embodiment of the present invention. 2 is a partial cross-sectional view showing the configuration of the riser tube support structure, and FIG. 3 is a partial plan view of the upper riser tube support structure. Although each figure shows only the port side, this support structure may be arranged on the starboard side or both sides.

The offshore floating structure 10 of the first embodiment is an FPSO facility provided with a processing facility for processing, for example, crude oil, gas, and the like. The offshore floating structure 10 is constructed, for example, by dividing it into blocks in the longitudinal direction, joining the blocks in the final process, and using a block construction method that constitutes the entire structure. After construction, the offshore floating structure 10 is self-propelled or towed and transferred to the installation sea area (water area), and after mooring in the same sea area (water area), a large number of flexible riser pipes R are attached (FIG. 2). reference).

The riser pipe R is guided to the seabed along the ship-side outer plate 12 of the offshore floating structure 10, and is used to fix the horizontal and vertical positions of each riser pipe R on the outside of the ship-side outer plate 12. The riser tube support structure 14 is attached. A large number of units constituting the riser pipe support structure 14 are arranged above the ship-side outer plate 12 at predetermined intervals along the longitudinal direction of the offshore floating structure 10.

The riser pipe support structure 14 hangs down into the sea with the upper riser pipe support structure 14A that holds and fixes the riser pipe R above the ship side outer plate 12 and below the ship side outer plate 12, for example, near the bilge under the water. A lower riser tube support structure 14B for holding the riser tube R is provided. The upper riser tube support structure 14A includes a cylindrical riser tube fixing tube 16 through which the riser tube R is inserted, and a bracket member 18 extending vertically outward from the ship side outer plate 12 and a riser. A fixing tube support structure portion 20 for structurally connecting the tube fixing tube 16 to the bracket members 18 on both sides thereof and the ship side outer plate 12 is provided.

The bracket member 18 is, for example, a trapezoidal plate-like structure whose lower portion has an inverted right-angled triangular shape, and projects vertically to the outside of the ship-side outer plate 12 along the longitudinal direction of the offshore floating structure 10 at predetermined intervals. Can be attached in shape. The riser tube fixing tube 16 is arranged one by one between two adjacent bracket members 18.

The lower riser tube support structure 14B is mainly composed of, for example, a cylindrical guide tube 22 that regulates the horizontal movement of the riser tube R. The guide tube 22 is provided along the longitudinal direction of the offshore floating structure 10, and is arranged substantially directly below each riser tube fixing tube 16 provided above. Further, the guide tube 22 is fixed to the ship side outer plate 12 via the guide tube support structure portion 24.

Inside the ship-side outer plate 12, a plurality of longitudinal ribs 26 extending in the longitudinal direction are provided as longitudinal members, and a stringer 30 is arranged near the upper deck 28. Further, side transformers 32 are provided as horizontal members at predetermined intervals S in the longitudinal direction. The offshore floating structure 10 adopts, for example, a double hull structure, and a longitudinal partition wall 34 is provided inside the ship side outer plate 12 at a position separated from the ship side outer plate 12 by a predetermined distance, and each side transformer 32 The inner side is connected to the longitudinal partition wall 34. Each side transformer 32 located above the stringer 30 may be provided with an opening 32A such as a manhole. An intermediate frame (reinforcing member) 36 is provided in parallel with the side transformer 32 at an intermediate position between the two side transformers 32 inside the ship side outer plate 12.

The bracket member 18 is attached to a position corresponding to the side transformer 32 and the intermediate frame (reinforcing member) 36 on the outside of the ship side outer plate 12. FIG. 4 is a partial cross-sectional view at the position of the intermediate frame (reinforcing member) 36, and as shown in FIG. 4, the intermediate frame (reinforcing member) 36 is partially along the vertical direction of the ship side outer plate 12. It is provided in. For example, the intermediate frame (reinforcing member) 36 extends from a predetermined position above the bracket member 18 attached to the ship-side outer plate 12 to a predetermined position below, and in the illustrated example, the upper end thereof is connected to the upper deck 28. Has been done.

As shown in FIG. 3, the fixed tube support structure portion 20 is configured with, for example, a distance S between two side transformers 32 (for example, about 4 m or more) as a unit, and one unit is, for example, fixed to two riser tubes. Tube 16 is included. The fixed tube support structure portion 20 sandwiches the riser tube fixing tube 16 and extends along the ship side outer plate 12 of the offshore floating structure 10 on the ship side outer plate 12 side and the opposite side (outside) of the ship side outer plate 12 side. A support member 21 is provided. Both ends of the longitudinal support member 21 are connected to and supported by the bracket member 18. On the outer surface of the cylinder of the riser tube fixing tube 16, two plate-shaped guide members 20A connecting between the front and rear bracket members 18 parallel to the ship side outer plate 12 and the left and right vertical guide members extending in the width direction of the ship. Two plate-shaped guide members 20B that communicate with the through support member 21 are provided. Further, the top surface of the fixed tube support structure portion 20, that is, the upper sides of the guide members 20A and 20B and the longitudinal support member 21 is covered with the top plate 20T, and the riser tube fixing tube 16 communicates the top plate 20T up and down. do. A pull-in module 38 used for mounting and installing the riser tube R is provided on the top plate 20T at the position where the bracket member 18 and the longitudinal support member 21 intersect (omitted in FIG. 1).

In the present embodiment, the diameter and the like of the riser tube fixing tube 16 may differ depending on the installation location, but the dimensions of each member of the upper riser tube support structure 14A are assumed in the upper riser tube support structure 14A. It is unified to the dimensions required for strength corresponding to the largest load to be applied, and is constant in the longitudinal direction. For example, the plate thickness of the longitudinal support member 21, the width in the vertical direction, the thickness of the top plate 20T, and the like are constant. As a result, the arrangement order of the pre-configured assembly can be changed in various ways according to the specifications of the riser pipe at each position determined after the design of the processing equipment installed in the offshore floating structure 10 is completed. However, there is no step in the dimensions of the members in the longitudinal direction, and inconveniences such as stress concentration are prevented from occurring. There may be a unit that does not have the riser tube fixing tube 16.

FIG. 5 is a plan view of the lower riser tube support structure 14B. Also in the lower riser pipe support structure 14B, the dimensions of each member in the longitudinal direction are unified to the dimensions required for strength corresponding to the largest load. Further, end structures 40 are provided before and after the upper and lower riser tube support structures 14A and 14B. Although only the end structure 40 of the lower riser tube support structure 14B is shown in FIG. 5, substantially similar end structures are provided before and after the upper riser tube support structure 14A.

As described above, according to the first embodiment, by providing the intermediate frame (reinforcing member) and the bracket member corresponding thereto, it is possible to provide a riser pipe support structure capable of withstanding a larger load.

Further, it takes time to determine the final arrangement of the riser pipe R, and therefore the type and arrangement of the riser pipe R may be changed after the start of construction of the offshore floating structure 10, but in the present embodiment, it is fixed. The tube support structure 20 is unitized, and the dimensions of the members in each unit in the longitudinal direction are constant (unified), and all the locations where the riser tube R may be arranged. By attaching the intermediate frame (reinforcing member) 36 to the riser tube fixing tube 16, it is possible to easily cope with the change of the riser tube fixing tube 16 due to the design change.

In assembling, a structure in which the fixing tube support structure portion 20 including the riser tube fixing tube 16 is attached to the bracket member 18 may be created and then attached to the ship side outer plate 12, but the bracket member may be attached in advance at the block stage. It is also possible to attach the 18 directly to the ship side outer plate 12 and attach the fixing tube support structure portion 20 including the riser tube fixing tube 16 to the bracket member 18 after connecting the block.

Further, as a modification, as shown in FIG. 6, a configuration in which two rows of riser tube fixing tubes 16 are provided in the fixed tube support structure portion 20 in the width direction is also possible. In this case, for example, the load per riser tube is conventionally. Even if it does not change, the number of riser tubes supported by each bracket member 18 is doubled, and the load applied to the support portion increases. The present invention can cope with an increase in load in such a case.

FIG. 7 is a partial plan view showing the configuration of the riser tube support structure of the second embodiment, and FIG. 8 is a partial cross-sectional view thereof. As in the first embodiment, each figure shows only the port side, but the support structure may be arranged on the starboard side or both sides. In each figure, the same reference numerals are used for the same configurations as those in the first embodiment, and the description thereof will be omitted.

In the riser tube support structure 14 of the first embodiment, the bracket member 18 supported by the intermediate frame (reinforcing member) 36 is arranged between the two riser tube fixing tubes 16, and the riser tube fixing tube 16 is a guide. It was held by the bracket member 18 supported by the side transformer 32 and the intermediate frame (reinforcing member) 36 via the members 20A and 20B. On the other hand, in the riser support structure 42 of the second embodiment, the structure of the bracket member 18 supported by the side transformer 32 is the same, but instead of the intermediate frame (reinforcing member) 36 and the bracket member 18 supported by the intermediate frame (reinforcing member) 36. A web member 46 for connecting the riser tube fixing tube 16 and the ship side outer plate 12 is provided at a position corresponding to the guide member 20B on the outer side of the ship side outer plate 12 in the first embodiment. Further, inside the ship side outer plate 12 corresponding to the web member 46, a reinforcing member 44 for supporting the web member 46 is provided as in the intermediate frame (reinforcing member) 36 for supporting the bracket member 18 in the first embodiment. Be done. Although not shown in FIG. 7, a guide member 20B may be provided on the opposite side of the web member 46 in the riser tube fixing tube 16 as in the first embodiment as shown in FIG.

The reinforcing member 44 is arranged parallel to the side transformer 32, for example, smaller than the intermediate frame (reinforcing member) 36, and outside the ship side from a position higher to a position lower than the portion attached to the ship side outer plate of the web member 46. It extends only to a partial area in the vertical direction of the board. An opening 46A such as a manhole for a person to pass through may be provided near the center of the web member 46, for example. On the other hand, the riser tube fixing tubes 16 and the riser tube fixing tube 16 and the bracket member 18 are connected by the guide member 20A as in the first embodiment, and the top of the fixing tube support structure portion 20 is covered by the top plate 20T. Will be. The other configurations of the second embodiment are the same as those of the first embodiment.

As described above, even in the configuration of the second embodiment, substantially the same effect as that of the first embodiment can be obtained.

It should be noted that various other configurations described in each embodiment and modification can be applied in various combinations in other embodiments as long as there is no contradiction in the structure. It is also possible to simultaneously adopt a configuration using an intermediate frame (reinforcing member) that supports the bracket member of the first embodiment and a configuration using a reinforcing member that supports the web member of the second embodiment.

10 Offshore floating structure 12 Ship side skin 14, 42 Riser tube support structure 14A Upper riser tube support structure 14B Lower riser tube support structure 16 Riser tube fixing tube 18 Bracket member 20 Fixed tube support structure part 20A, 20B Guide member 20T Top plate 21 Vertical support member 22 Guide tube 26 Vertical rib 28 Upper deck 30 Stringer 32 Side transformer 34 Vertical partition 36 Intermediate frame (reinforcing member)
38 Pull-in module 40 End structure 44 Reinforcing member 46 Web member R Riser tube

Claims (8)

A riser pipe support structure for holding and fixing a large number of riser pipes to the ship's side skin along the longitudinal direction of the offshore floating structure.
A riser tube fixing tube that holds and fixes the riser tube to be inserted,
A fixing tube support structure for supporting the riser tube fixing tube,
A bracket member that supports the fixed tube support structure and
Side transformers provided inside the ship-side outer panel at predetermined intervals along the longitudinal direction,
A reinforcing member provided in parallel with the side transformer between the side transformers inside the ship side outer plate and supporting the fixed tube support structure portion, and a reinforcing member .
A web member for connecting between the riser tube fixing tube and the ship side outer plate is provided.
A riser tube support structure characterized in that the bracket member is attached to the outside of the ship side outer plate along the side transformer, and the web member is attached to the ship side outer plate along the reinforcing member. A riser pipe support structure for holding and fixing a large number of riser pipes to the ship's side skin along the longitudinal direction of the offshore floating structure.
A riser tube fixing tube that holds and fixes the riser tube to be inserted,
A fixing tube support structure for supporting the riser tube fixing tube,
A bracket member that supports the fixed tube support structure and
Side transformers provided inside the ship-side outer panel at predetermined intervals along the longitudinal direction,
It is provided with a reinforcing member provided in parallel with the side transformer between the side transformers inside the ship side outer plate and supporting the fixed tube support structure portion.
The bracket member is attached to the outside of the ship-side outer plate along the side transformer, and the position where the top plate of the fixed tube support structure is attached to the ship-side outer plate is provided inside the ship-side outer plate. Matches the height of the stringer
The riser tube support structure is characterized by this. 1 or claim 1, wherein the reinforcing member is an intermediate frame provided in parallel with the side transformer, and the bracket member is attached to the outside of the ship side outer plate along the intermediate frame. Item 2. The riser tube support structure according to item 2. A partial range of the reinforcing member in the vertical direction of the ship-side outer plate from a position higher to a position lower than the portion of the bracket member or the web member attached to the ship-side outer plate inside the ship-side outer plate. The riser tube support structure according to any one of claims 1 to 3, wherein the riser tube support structure is characterized in that it extends only to. The riser tube support structure according to any one of claims 1 to 4 , wherein the dimensions of each member along the longitudinal direction of the fixed tube support structure portion are constant. The fixed tube support structure having a predetermined length capable of supporting a predetermined number of riser tube fixing tubes is configured as a unit, and a plurality of the units connected in the longitudinal direction can be attached to the offshore floating structure in units. The riser tube support structure according to any one of claims 1 to 5, wherein the riser tube support structure is characterized. The riser tube support structure according to any one of claims 1 to 6 , wherein the fixed tube support structure portion supports the riser tubes in two rows in the width direction. An offshore floating structure having the riser tube support structure according to any one of claims 1 to 7.

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