Subsea Composite Vessel

Abstract

It is described cylindrical subsea vessel (1) for separation of a flow, the vessel (1) comprising first and second longitudinal ends (T,1″), wherein the subsea vessel (1) comprises: —a liner (2); —at least one fluid inlet (3) and one fluid outlet (4, 5) into and out of an inner volume (7) of the vessel (1); —at least one flange (8) connected in one of the longitudinal ends (1′, 1″), wherein the at least one flange (8) and the liner (2) form the inner volume of the subsea vessel (1), and wherein the at least one flange (8) comprises at least one through-going opening (4,5,6) forming the at least one fluid inlet (3,4) and/or fluid outlet (5); —a load bearing structure (9) arranged outside the liner (2) and the at least one flange (8), wherein the load bearing structure (9) is of a composite material. It is further described a method of manufacturing the subsea vessel.

Claims

1. A cylindrical subsea vessel for separation of a flow, the vessel comprising: first and second longitudinal ends; a liner; at least one fluid inlet and at least one fluid outlet connected to an inner volume of the vessel; at least one flange connected to one of the first and second longitudinal ends, wherein the at least one flange and the liner form the inner volume of the subsea vessel, and wherein the at least one flange comprises at least one through-going opening forming the at least one fluid inlet and/or the at least one fluid outlet; and a load bearing structure arranged outside the liner and the at least one flange, wherein the load bearing structure is made of a composite material; and wherein the liner and the at least one flange are made of the same material.

2. The subsea vessel according to claim 1, wherein the vessel comprises two flanges, and wherein each flange is connected to a respective one of the first and second longitudinal ends of the vessel.

3. The subsea vessel according to claim 1, wherein the vessel comprises only one flange.

4. The subsea vessel according to claim 3, wherein the one flange comprises a first and a second through-going opening, and wherein the first through-going opening forms the fluid inlet and the second through-going opening forms the fluid outlet.

5. The subsea vessel according to claim 4, further comprising an inlet pipe extending from the one flange towards an opposite longitudinal end of the subsea vessel for directing fluid into the subsea vessel.

6. The subsea vessel according to claim 1, wherein all through-going openings for inlet and/or outlet of fluid into and out of the inner volume of the vessel are arranged in the at least one flange connected to the at least one longitudinal end of the vessel.

7. The subsea vessel according to claim 1, wherein the composite material of the load bearing structure comprises a Carbon Fiber Reinforced Polymer (CFRP).

8. The subsea vessel according to claim 1, wherein the vessel further comprises a coating outside the composite material.

9. The subsea vessel according to claim 8, wherein the coating is a thermoplastic coating.

10. The subsea vessel according to claim 1, wherein the liner is a metallic liner, and wherein the vessel comprises a galvanic coupling protection for the metallic liner, the galvanic coupling protection being arranged between the metallic liner and the load bearing structure.

11. The subsea vessel according to claim 10, wherein the galvanic coupling protection is a Glass Fiber Reinforced Polymer (GFRP).

12. A cylindrical subsea vessel comprising: first and second longitudinal ends; at least one fluid inlet and one fluid outlet connected to an inner volume of the vessel; at least one flange connected to one of the longitudinal ends, wherein the at least one flange comprises at least one through-going opening forming the at least one fluid inlet and/or the at least one fluid outlet; and a structure forming the vessel, wherein the structure is made of a composite material.

13. A method of manufacturing a cylindrical subsea vessel, the vessel having first and second longitudinal ends, the method comprising: preparing a liner; preparing at least one flange comprising at least one through-going opening forming a fluid inlet or a fluid outlet, wherein the liner and the at least one flange are made of the same material; forming a fluid-tight connection between the at least one flange and the liner to thereby provide a closed inner volume inside the liner and the at least one flange; and forming a load bearing structure of a composite material outside the liner and the at least one flange.

14. The method according to claim 13, further comprising: adding an external coating outside the composite material.

15. The method according to claim 13, further comprising, after the step of forming the fluid-tight connection: pressurizing the closed inner volume of the subsea vessel.

16. The method according to claim 13, further comprising, prior to forming the load bearing structure: adding an elastomeric sealing layer over the liner and the at least one flange; and adding a galvanic coupling protection of a glass fiber reinforced plastic over the elastomeric sealing layer.

17. The method according to claim 14, further comprising, prior to adding the external coating: adding glass fiber reinforced polymer (GFRP) composite protective shell over the load bearing structure.

18. The subsea vessel according to claim 1, wherein the liner and the at least one flange are made of the same metal.

19. The method according to claim 13, wherein the liner and the at least one flange are made of the same metal.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0064] The following drawings are appended to facilitate the understanding of the invention. The drawings show embodiments of the invention, which will now be described by way of example only, where:

[0065] FIGS. 1A, 1B and 1C are examples of a cylindrical subsea vessel according to the invention, where FIG. 1A is a view along a longitudinal axis of the subsea vessel, FIG. 1B is a side view of the subsea vessel and FIG. 1C is a perspective view of the subsea vessel;

[0066] FIG. 2 is a perspective view of details of the different layers in a subsea vessel according to the invention;

[0067] FIG. 3A is a perspective view of an inner volume of a subsea vessel, where the vessel has been cut in a vertical plane along its longitudinal axis;

[0068] FIG. 3B is an enlarged view of section a in FIG. 3B, showing details of a particulate removal system which may be arranged inside an inner volume of the subsea vessel;

[0069] FIG. 4 is a perspective side view of a subsea vessel, indicating different layers forming the subsea vessel;

[0070] FIG. 5 is a side view of a subsea vessel with only one flange, where all of the fluid inlet(s) and fluid outlet(s) into and out of the subsea vessel are arranged in said one flange;

DETAILED DESCRIPTION OF THE INVENTION

[0071] In the following, embodiments of the invention will be discussed in more detail with reference to the appended drawings. It should be understood, however, that the drawings are not intended to limit the invention to the subject-matter depicted in the drawings.

[0072] FIGS. 1A,1B and 1C are examples of a cylindrical subsea vessel 1 according to the invention, where FIG. 1A is a view along a longitudinal axis of the subsea vessel, FIG. 1B is a side view of a subsea vessel 1, and FIG. 1C is a perspective view of the subsea vessel 1.

[0073] FIG. 2 is a perspective view of details of the different layers in a subsea vessel according to the invention. The layers of the disclosed subsea vessel 1 in FIG. 2 are the following, starting from the innermost layer: [0074] Liner 2 and flange 8. The liner 2 and the flange 8 are connected to each other by a fluid-tight connection, such as by welding or gluing and may be the only structural components of the subsea vessel 1 that are in the contact with the fluid, e.g., production fluid. In order to protect the flange(s) 8, the flange(s) 8 may have weld overlaid cladding 19 placed on the flange surfaces exposed to the fluid inside the vessel. [0075] An elastomeric sealing layer 17 over the liner 2 and the at least one flange 8. [0076] A galvanic coupling protection 12 for the liner 2. The galvanic coupling protection 12 may be a Glass Fiber Reinforced Polymer (GFRP). [0077] A load bearing structure 9. The load bearing structure may be formed of a composite material, such as Carbon Fiber Reinforced Polymer (CFRP). [0078] A glass fiber reinforced polymer (GFRP) composite protective shell 18 over the load bearing structure 9. The shell 18 is preferably made to provide protection against impacts and minor damages, as well as to provide additional galvanic insulation between the load bearing structure 9 and external metallic parts. [0079] An external coating 11.

[0080] FIG. 3A is a perspective view of an inner volume 7 of a subsea vessel 1. The vessel 1 in FIG. 3A has been cut in a vertical plane along its longitudinal axis to better illustrate internal devices or components of the subsea vessel 1. The subsea vessel 1 of FIG. 3A discloses a liner 2 extending from the first longitudinal end 1′ to the second longitudinal end 1″ of the vessel 1. A total of two flanges 8 are shown, the flanges 8 are connected to respective longitudinal ends 1′,1″ of the vessel 1 forming a fluid tight connection therebetween. The flange 8 connected to the first longitudinal end 1′ of the vessel 1 comprises a through-going opening forming a fluid inlet 3 for production fluid into the inner volume 7 of the subsea vessel 1. The arrow A1 inside the inner volume 7 indicates the flow direction inside the subsea vessel 1. The flange 8 connected to the second longitudinal end 1″ of the vessel 1 is disclosed with a total of three through-going openings forming a fluid outlet 4 for production fluid, a fluid outlet 5 for gas outlet and a fine particulate outlet 6.

[0081] As disclosed in the FIG. 3A, the fluid outlet 5 for gas is connected to a gas pipe 20 inside the subsea vessel 1. As the gas separates higher relative to liquids, the gas pipe 20 has an inlet at a relatively high elevation inside the inner volume 7.

[0082] Further, as disclosed in FIG. 3A, the fluid outlet 4 for production fluid is connected to a production fluid pipe 21 inside the subsea vessel 1. The inlet of the production fluid pipe 21 is at a relatively lower elevation compared to the inlet of the gas pipe 20.

[0083] The elevation of the inlets of the gas pipe 20 and the fluid production pipe 21 are chosen based on expected well flow composition etc., and can be varied.

[0084] It is further disclosed a fine particulate outlet 6. The fine particulate outlet 6 is connected to a fine particulate pipe 22 inside the subsea vessel 1. The fine particulate outlet and fine particulate pipe form part of a particulate removal system 13.

[0085] The particulate removal system 13 (which is better illustrated in FIG. 3B) is further disclosed with a particle movement device 14 for forcing any sedimented particles from the flow into motion and towards a particle removal device 16 which is connected to the fine particulate pipe 22 and the fine particulate outlet 6. The particle movement device 14 is disclosed with nozzles connected to a pressure system for jetting the sedimented particles.

[0086] The particle removal device 16 is conically with the relatively larger cross section of the cone directed downwards towards the sedimented particles/sediments (which due to their relative higher density than the fluids, will collect at the bottom of the subsea vessel 1). This may provide a more efficient suction of the particles or sediments than using a pipe with a constant cross section.

[0087] If used as a gravitational separator, the internals encompass all the devices in the multiphase separation process, such as inlet diverter, sand removal system, weir plates, internal piping, demisters, etc. These components are preferably modular and comply with the same boundary conditions as established for the liner 2 and flange(s) 8.

[0088] FIG. 3B is an enlarged view of section a in FIG. 3B, showing details of a particulate removal system 13 which may be arranged inside the inner volume 7 of the subsea vessel 1. The particle movement device 14 is illustrated as nozzles. The nozzles are arranged along substantially the whole length of the subsea vessel, e.g., from the first longitudinal end 1′ of the vessel 1 to the second longitudinal end 1″ of the vessel 1. The outlets of the nozzles are arranged with a space relative an outlet of a neighboring nozzle.

[0089] FIG. 4 is a perspective side view of a subsea vessel 1, indicating different components the subsea vessel 1. The components are similar to the layers described in relation to FIG. 2.

[0090] FIG. 5 is a side view of a subsea vessel 1 with only one flange 8. All of the fluid inlets and outlets 3, 4, 5 i.e., fluid inlet 3 for production fluid, fluid outlet 4 for production outlet and fluid outlet 5 for gas outlet into and out of the inner volume 7 of the subsea vessel 1 are arranged in said one flange 8. In addition, the fine particulate outlet 6 for the fine particles are arranged in the same flange 8. Thus, the flange 8 has through-going openings for the respective inlets and outlets 3,4,5,6 into and out of the inner volume 7 of the subsea vessel 1. A similar particulate removal system 13 comprising particle movement device 13, particle removal device 16 and fine particulate pipe 22 as the system illustrated and described in relation to FIGS. 3A and 3B are arranged inside the inner volume 7 of the subsea vessel 1 and will not be further described. The fluid inlet 3 extending through the flange 8 is connected to an inlet pipe 10. The inlet pipe 10 extends from the one flange 8 arranged at the second longitudinal end 1″ of the vessel 1 and to an opposite end of the subsea vessel, i.e., to the first longitudinal end 1′ of the vessel 1. This means that production fluid entering via fluid inlet 3 and further to the inlet pipe 10 is discharged from the inlet pipe 10 at the opposite end of the subsea vessel 1 than where the one flange 8 is arranged. The retention time for the fluid in the subsea vessel 1 is similar to arranging the inlet and outlet at the opposite longitudinal ends (as in FIGS. 1-4) provided that the subsea vessels 1 are of the same size and the discharge outlet from the inlet pipe 10 is at or close to the first longitudinal end 1′ of the subsea vessel 1.

[0091] In the preceding description, various aspects of the subsea vessel according to the invention have been described with reference to the illustrative embodiment. For purposes of explanation, specific numbers, systems and configurations were set forth in order to provide a thorough understanding of the subsea vessel and its workings. However, this description is not intended to be construed in a limiting sense. Various modifications and variations of the illustrative embodiment, as well as other embodiments of the subsea vessel, which are apparent to persons skilled in the art to which the disclosed subject matter pertains, are deemed to lie within the scope of the present invention as defined in the attached claims.

LIST OF REFERENCE NUMBERS

[0092] 1 Subsea vessel [0093] 2 Liner [0094] 1′,1′ First and second longitudinal ends of subsea vessel [0095] 3 Fluid inlet [0096] 4 Fluid outlet, production fluid outlet [0097] 5 Fluid outlet, gas outlet [0098] 6 Fine particulate outlet [0099] 7 Inner volume of vessel [0100] 8 Flange [0101] 9 Load bearing structure [0102] 10 Inlet pipe [0103] 11 Coating [0104] 12 Galvanic coupling protection [0105] 13 Particulate removal system [0106] 14 Particle movement device [0107] 16 Particle removal device [0108] 17 Elastomeric sealing layer [0109] 18 Glass fiber reinforced polymer composite protective shell [0110] 19 Flange cladding [0111] 20 Gas pipe [0112] 21 Fluid production pipe [0113] 22 Fine particulate pipe [0114] A Section/enlarged portion [0115] A1 Arrow indicating flow direction