Floating structure

Abstract

The invention relates to a floating production storage and offloading (FPSO) or floating production storage and storage (FSO) structure comprising: a hull adapted to support a weight of at least 50.000 tons, preferably at least 70.000 tons, side walls having a length L extending in a longitudinal direction, a bottom structure and an upper deck, the hull having a width B; a treatment unit support structure above the upper deck; a hydrocarbon processing unit mounted on the processing unit support structure; the outer portion of the hull comprises: side spaces delimited by a bottom structure, an upper deck, respective side walls and adjacent longitudinal side walls located at a distance Wt from the side walls, Wt being at least equal to a minimum of 0.2 B or 11.5 m, the inner portion of the hull comprising: at least one hydrocarbon storage compartment for storing hydrocarbons, and an upper deck located between the bottom structure, the upper deck and adjacent longitudinal walls, where the vessel comprises a middle longitudinal bulkhead and one to four hydrocarbon storage tanks of substantially identical size extending in a transverse direction between adjacent longitudinal side walls and the middle longitudinal bulkhead.

Description

Technical Field

[0001] The present invention relates to a floating production storage and offloading (FPSO) or floating production storage and offloading (FSO) structure, which comprises: a hull having side walls of a length L extending in a longitudinal direction, a bottom structure and an upper deck, the hull having a width B; a processing unit support structure located above the upper deck; a hydrocarbon processing equipment unit mounted on the processing unit support structure; and a pipeline connecting the processing unit with at least one hydrocarbon storage tank for storing processed hydrocarbons. Background Art

[0002] Large floating structures (such as FPSO or FSO structures) are moored offshore in a multi-point mooring or wind-steerable configuration, for example, near offshore hydrocarbon production wells. FPSOs include multiple risers extending from a riser platform (or from an internal turret or an external turret) to one or more wellheads. The upper deck structure carries processing units for processing the produced hydrocarbons, which are stored in tanks located inside the hull. As an example, the weight of the superstructure of a known floating structure can be up to 50,000 tons, the length of the floating structure can be 330m, the width can be 60m, the draft can be 25m, the height above water can be 40m, and it can include 19 crude oil tanks. The object of the present invention is to provide a floating structure that can support a larger superstructure and provide improved safety and protection for hydrocarbon tanks in the event of a collision. Another object is to provide a large floating structure of relatively simple configuration, wherein the number of hydrocarbon tanks can be reduced, thereby reducing pumps, reducing maintenance, and reducing visits. Another object is to provide a floating structure in which the unloading sequence of hydrocarbons is improved. Summary of the invention

[0003] According to the present invention, there is provided a floating structure comprising: a hull adapted to support a weight of at least 50,000 tonnes, preferably at least 70,000 tonnes, the hull having side walls extending in a longitudinal direction of length L, a bottom structure and an upper deck, the hull having a width B; a processing unit support structure located above the upper deck; a hydrocarbon processing unit mounted on the processing unit support structure; and at least one hydrocarbon storage tank for storing hydrocarbons,

[0004] - the side space is defined by the bottom structure, the upper deck, the corresponding side wall and the adjacent longitudinal side wall, the adjacent longitudinal side wall being located at a distance Wt from the side wall, Wt being at least equal to the minimum of 0.2B or 11.5m,

[0005] - The at least one hydrocarbon storage tank is located between the bottom structure, the upper deck and the adjacent longitudinal walls.

[0006] The floating structure according to the invention provides large side spaces (or wing tanks) between the side walls and the hydrocarbon storage tanks so that in the event of a collision, deformation is limited to the area of ​​the wing tanks, complying with the MARPOL definition of damage, while the hydrocarbon storage tanks are protected. The side spaces (or wing tanks) can be filled with ballast water, or can contain equipment, or can be empty.

[0007] The design may include a single bottom or a double bottom.

[0008] The vessel may comprise a mid-longitudinal bulkhead and a plurality of hydrocarbon storage tanks (1 to 4 tanks of substantially the same size) extending in a transverse direction between adjacent longitudinal side walls and the mid-longitudinal bulkhead.

[0009] The design provides a reduced number of equally sized hydrocarbon storage tanks (such as crude oil tanks), thereby improving unloading because less time is required to switch between tanks and the unloading time for all tanks is similar.

[0010] The storage compartment may be located between front and rear transverse walls extending in a transverse direction from adjacent longitudinal side walls to the central longitudinal bulkhead.

[0011] In addition to the central longitudinal bulkhead, the floating structure according to the invention comprises one or more longitudinal bulkheads, between which the crude oil tanks are located.

[0012] Since in the preferred embodiment a relatively small number of bulkheads are provided, the configuration of the floating structure according to the invention is simplified.

[0013] The processing unit may be placed on the upper deck structure, above the longitudinal and transverse bulkheads, to form a solid support structure. The processing unit may be mounted on the upper deck structure, in a position above the side spaces, to achieve optimal utilization of the available deck space. The processing unit support structure may form an integral part of the upper module, mounted on the upper deck by supports or legs.

[0014] The floating structure may include a hydrocarbon riser extending from the floating structure to the subsea well, a pipeline connecting the riser with the processing unit. The riser may extend through the side space.

[0015] The side spaces can be provided with special internal reinforcement structures for the riser platform and / or the mooring structure. Depending on the specific design requirements, the riser platform and / or the mooring connector can be attached to the reinforcement structure.

[0016] In an embodiment, the side space comprises a water tank and the floating structure comprises a pump adapted for filling and emptying the water tank. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Embodiments of the floating structure according to the invention will be explained in detail by way of non-limiting examples with reference to the accompanying drawings. In the drawings:

[0018] Figure 1 shows a schematic plan view of a floating structure according to the present invention,

[0019] Figure 2 Shows Figure 1 A schematic transverse cross-sectional view of a floating structure,

[0020] Figure 3 Shows Figure 1 a transverse cross-section of the hull of the floating structure, and

[0021] Figure 4 Shows Figure 3 A perspective view of the hull section. DETAILED DESCRIPTION

[0022] Figure 1 A plan view of a floating structure 1 is shown, the floating structure having a hull 2 ​​with side walls 3, 4, a bow 6 and a stern 8. The length L of the structure 1 is at least about 380m and the width B is at least about 64m. The structure 1 comprises longitudinal bulkheads 10, 11 and a mid-longitudinal bulkhead 12 extending from the stern 8 to the bow 6. The longitudinal bulkheads 10, 11 are at a transverse distance Wt from the side walls 3, 4 of at least 0.2B or 11.5m, whichever is smaller, in this example 11.5m. Transverse bulkheads 15, 16, 17, 18 extend in a transverse direction between the side walls 3, 4, so that spaces (or wing tanks) 20, 21, 22, 23, 24, 25 are formed by the space bounded by the side walls 3, 4, the longitudinal bulkheads 10, 11, and the transverse bulkheads 15, 16, 17, 18. The crude oil tanks 30, 31, 32, 33, 34, 35 are located between the longitudinal bulkheads 10, 11, on either side of the mid-longitudinal bulkhead 12. The twelve crude oil tanks 30-35 are substantially the same size. Other arrangements with different numbers and different configurations of cargo tanks may be provided.

[0023] Figure 2 A schematic transverse cross section of a floating structure 1 having a bottom 7 and an upper deck 9 is shown. The bottom 7 may be formed by a single plate, or may be formed by a double-walled bottom structure. The height H may be about 34 m. A processing unit support structure 40 in the form of an integral deck, or a plurality of separate processing unit support structures, is placed on supports 41, 42 and carries processing units 43, 44, with a total weight of the top structure of about 50,000 to 100,000 tons. A riser 50 may be supported on a riser platform 51, connected to a wellhead 52 on the seabed 53. The riser 50 is connected to the processing units 43, 44 via pipes 54, 56 and a pump 55 to separate gas and water from the produced oil, and to store the treated oil in crude oil tanks 30-35.

[0024] Figure 3 A cross-section of the hull 2 ​​and transverse bulkheads is shown.

[0025] Figure 4 Shows Figure 3 A perspective view of a portion of the hull 2 ​​is shown.

Claims

1. A floating production storage and offloading (FPSO) or floating production storage and offloading (FSO) structure (1), comprising: a hull (2) adapted to support a weight of at least 50.000 tonnes, preferably at least 70.000 tonnes, the hull having side walls (3, 4) extending in longitudinal direction with a length L, a bottom structure (7) and an upper deck (9), the hull (2) having a width B; a processing unit support structure (40) located above the upper deck (9); a hydrocarbon processing unit (43, 44) mounted on the processing unit support structure (40); The outer part of the hull includes: - side spaces (20, 21, 22, 23, 24, 25), said side spaces being delimited by said bottom structure (7), said upper deck (9), the respective side walls (3, 4) and adjacent longitudinal side walls (10, 11), said adjacent longitudinal side walls (10, 11) being located at a distance Wt from said side walls (3, 4), Wt being at least equal to the minimum of 0.2B or 11.5 m, The internal part of the hull includes: At least one hydrocarbon storage tank (30, 31, 32, 33, 34, 35) for storing hydrocarbons, the hydrocarbon storage tank being located between the bottom structure (7), the upper deck (9) and the adjacent longitudinal side walls (10, 11), wherein the ship comprises a mid-longitudinal bulkhead (12) and one to four hydrocarbon storage tanks of substantially the same size, the hydrocarbon storage tanks extending in a transverse direction between the adjacent longitudinal side walls (10, 11) and the mid-longitudinal bulkhead (12).

2. The floating production storage and offloading (FPSO) or floating production storage and offloading (FSO) structure (1) according to claim 1, characterized in that: The hydrocarbon storage tank is located between front and rear transverse walls (15, 16, 17, 18) extending in the transverse direction from adjacent longitudinal side walls (10, 11) to the central longitudinal bulkhead (12).

3. A floating production storage and offloading (FPSO) or floating production storage and offloading (FSO) structure (1) according to any one of the preceding claims, characterized in that: The processing units (43, 44) are placed on the processing unit support structure (40) above the adjacent longitudinal side walls (10, 11) and transverse walls (15, 16, 17, 18).

4. A floating production storage and offloading (FPSO) or floating production storage and offloading (FSO) structure (1) according to any one of the preceding claims, characterized in that: The processing unit support structure (40) is supported on the upper deck (9) at a position above the side spaces (20, 21, 22, 23, 24, 25).

5. A floating production storage and offloading (FPSO) or floating production storage and offloading (FSO) structure (1) according to any one of the preceding claims, characterized in that: The structure comprises a hydrocarbon riser (50) extending from the hull (2) to a subsea well (53), and pipelines (54, 56) connecting the riser (50) to the processing units (43, 44).

6. A floating production storage and offloading (FPSO) or floating production storage and offloading (FSO) structure (1) according to any one of the preceding claims, characterized in that: The riser pipes extend vertically in the side spaces (20, 21, 22, 23, 24, 25).

7. A floating production storage and offloading (FPSO) or floating production storage and offloading (FSO) structure (1) according to any one of the preceding claims, characterized in that: The side spaces (20, 21, 22, 23, 24, 25) are provided with internal reinforcement structures for riser platforms and / or mooring structures.

8. A floating production storage and offloading (FPSO) or floating production storage and offloading (FSO) structure (1) according to any one of the preceding claims, characterized in that: The side spaces (20, 21, 22, 23, 24, 25) comprise water tanks, and the FPSO or FSO structure comprises pumps adapted for filling and emptying the water tanks.

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