System and method for temporarily connecting an underwater station and a surface facility

Abstract

A system for temporarily connecting an underwater station arranged on the bed of a body of water and a surface facility has an elongated conducting member with one end connected to the underwater station and one free end selectively and temporarily connectable to the surface facility; a marker buoy; and a cable connected to the free end of the elongated conducting member and to the marker buoy to quickly recover the free end of the elongated conductor element when it is necessary to connect the underwater station via the elongated conducting member to the surface facility.

Claims

1. A system comprising: an underwater station comprising a tank configured to contain a service fluid; a surface facility; an elongated conducting member having one end connected to the tank of the underwater station and a free end selectively connectable to the surface facility; a cable having one end connectable to the free end of the elongated conducting member and another end connectable to a marker buoy; and an anchoring device configured to connect a portion of the elongated conducting member adjacent to the end connected to the tank of the underwater station to a bed of a body of water.

2. The system of claim 1, further comprising a depth buoy slidably coupled to the elongated conducting member and configured to temporarily keep the free end of the elongated conducting member at the depth buoy.

3. The system of claim 2, further comprising a mooring line connecting the depth buoy to the bed of the body of water.

4. The system of claim 2, wherein: the depth buoy comprises a sleeve slidably coupled around the elongated conducting member, and the free end of the elongated conductor member is integral with a head connectable to at least one of a pipe of the surface facility and an electrical cable of the surface facility.

5. The system of claim 4, wherein the sleeve defines a flared end.

6. The system of claim 4, wherein the sleeve is configured for supporting the head.

7. The system of claim 4, wherein the sleeve defines a slanted end.

8. The system of claim 4, wherein the depth buoy comprises a buoyancy module arranged around the sleeve.

9. The system of claim 4, wherein the head defines an end structure integral with the elongated conducting member and a flange configured to be coupled to the end structure and the cable.

10. The system of claim 1, wherein the anchoring device comprises: a double flared sleeve fixedly fitted around the elongated conducting member; an anchoring cable connected to the double flared sleeve; and a buoyancy module fixed to the elongated conducting member upstream of the double flared sleeve.

11. The system of claim 1, wherein the surface facility comprises a lifting device configured to lift the free end of the elongated conducting member above the body of water.

12. The system of claim 11, wherein the surface facility comprises a hooking structure configured to hook the free end of the elongated conducting member onto an edge of the surface facility.

13. A system comprising: an elongated conducting member having one end connected to a tank of an underwater station and a free end selectively connectable to a surface facility; a cable having one end connectable to the free end of the elongated conducting member and another end connectable to a marker buoy; and an anchoring device configured to connect a portion of the elongated conducting member adjacent to the end connected to the tank of the underwater station to a bed of a body of water.

14. The system of claim 13, further comprising a depth buoy slidably coupled to the elongated conducting member and configured to temporarily keep the free end of the elongated conducting member at the depth buoy.

15. The system of claim 14, wherein: the depth buoy comprises a sleeve slidably coupled around the elongated conducting member, and the free end of the elongated conductor member is integral with a head connectable to at least one of a pipe of the surface facility and an electrical cable of the surface facility.

16. The system of claim 15, wherein the head defines an end structure integral with the elongated conducting member and a flange which is configured to be coupled to the end structure and the cable.

17. The system of claim 13, wherein the anchoring device comprises: a double flared sleeve fixedly fitted around the elongated conducting member; an anchoring cable connected to the double flared sleeve; and a buoyancy module fixed to the elongated conducting member upstream of the double flared sleeve.

18. A method for connecting an underwater station and a surface facility, the method comprising: recovering, via the surface facility, a marker buoy connected by a cable to a free end of an elongated conducting member having another end connected to the underwater station, wherein a portion of the elongated conducting member adjacent to the end connected to the underwater station is connected, by an anchoring device, to a bed of a body of water; recovering, via the surface facility, the free end of the elongated conducting member; securing the free end of the elongated conducting member to the surface facility; and transferring fluid to a tank of the underwater station from the surface facility through the elongated conducting member.

19. The method of claim 18, wherein the other end of the elongated conducting member is permanently connected to the underwater station.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) Further characteristics and benefits of the present disclosure will be apparent from the following description of a non-limiting example of an embodiment of it, with reference to the Figures of the attached drawings, wherein:

(2) FIG. 1 is a schematic view, with parts removed for clarity, of a system for temporarily connecting an underwater station and a surface facility in accordance with the present disclosure;

(3) FIG. 2 is a longitudinal section view, with parts removed for clarity, of a detail of the system of FIG. 1;

(4) FIG. 3 is a section view, in enlarged scale and with parts removed for clarity, of an element of the system element of FIG. 1;

(5) FIGS. 4 and 5 show two lateral views, with parts removed for clarity, of two respective components of the system which is the object of the present disclosure;

(6) FIGS. 6 and 7 are side elevation views, with parts removed for clarity, of the system which is the object of the present disclosure during the step of recovering an elongated conducting member;

(7) FIGS. 8 and 9 are lateral elevation views, with parts removed for clarity, of an alternative embodiment of the system which is the object of the present disclosure; and

(8) FIGS. 10 and 11 are two lateral views, with parts removed for clarity and parts in section, of two respective components of the system, which is the object of the present disclosure.

DETAILED DESCRIPTION

(9) With reference to FIG. 1, a system 1 configured to temporarily connect an underwater station 2 and a surface facility 27 is shown in its entirety; in this case, the surface facility 27 is a ship 27 comprising a lifting device 28 and a hooking structure 29. While, the surface facility 27 shown is a ship, it should be appreciated that the surface facility could be a relatively small barge or a relatively small vessel.

(10) The system 1 comprises a depth buoy 3; an elongated conducting member 4 permanently connected to the underwater station 2; a marker buoy 5; and a cable 6 connected to the free end of the elongated conducting member 4 and to the marker buoy 5. The depth buoy 3 is anchored to the bed of the body of water by a single mooring line 7. In FIG. 1, the mooring line 7 is anchored to the bed of the body of water by appropriate foundations, for example gravity foundations, on piles or suction piles, depending on the type of soil. In this case, the position of the elongated conducting member 4 is restricted to being near the underwater station 2 to limit movements of the elongated conducting member 4 to near the landing point of the elongated conducting member 4. Control of the position of the elongated conducting member 4 is carried out by a control device which comprises a cable 8, which is anchored to the bed of the body of water; a sleeve 9 which is flared at opposite ends, and is connected to the cable 8; and a series of buoyancy modules 10 which provide upward thrust to the elongated conducting member 4 upstream of the sleeve 9. The elongated conducting member 4 is housed in a sleeve 9 and is anchored to the sleeve 9 so that the elongated conducting member cannot slide.

(11) The underwater station 2 is an underwater station configured to process hydrocarbons, of the type described in the EP Patent Application No. 3,054,083 and EP Patent Application No. 3,253,945 belonging to the applicant. In this case, the underwater station 2 comprises a plurality of tanks 11, 12, and 13 configured to contain chemicals or other service fluids. The tanks 11, 12 and 13 are storage tanks and are configured to operate in a body of water even at relatively great depths.

(12) With reference to FIG. 2, the depth buoy 3 comprises a sleeve 14 with a flared end 17; a plurality of buoyancy modules 15 arranged around the sleeve 14 and attached to the sleeve 14; and a stiffening element 16, which is arranged around the elongated conducting member 4 and is attached to the sleeve 14 at the opposite end to the flared end 17.

(13) In more detail, the sleeve 14 has a slanted end 18 which is slanted with respect to the rest of the sleeve 14. The slanted end 18 is arranged at the opposite end to the flared end 17. The stiffening element 16 is attached to the slanted end 18. The mooring line 7 is attached to the lower part of the sleeve 14 and defines, together with the depth buoy 3 and the elongated conducting member 4, a system which has different equilibrium points depending on the position of the elongated conducting member 4 with respect to the depth buoy 3.

(14) The diameter of the elongated conducting member 4, which depends on the number and characteristics of the necessary functions which may vary from project to project, is smaller than the minimum diameter of the sleeve 14 so as to enable the elongated conducting member 4 to slide relatively easily inside the depth buoy 3 and has a head 19 with a diameter, or in general transverse dimensions, greater than the maximum diameter of the sleeve 14 so as to prevent removal of the elongated conducting member 4 from the depth buoy 3.

(15) In the present disclosure, the term “elongated conducting member” means a pipe for conducting fluids or a cable for conducting energy or signals or a bundle of pipes and/or cables for conducting fluids and/or energy and/or signals or an umbilical.

(16) With reference to FIG. 3, the elongated conducting member 4 is shown as an umbilical and comprises a containment element 20; and a plurality of pipes 21, which are arranged inside the containment element 20 and are used to convey the respective service fluids, in this case, the respective chemicals or other service fluids. In sections wherein the elongated conducting member 4 slides relative to the depth buoy 3 and the sleeve 9, the containment element 20 is protected by a protective sheath G, which facilitates sliding of the elongated conducting member 4 in the depth buoy 3 and protects the containment element 20 from wear. In the case shown, the elongated conducting member 4 also comprises a plurality of electrical power cables 22 and electrical and/or fibre optic data cables 23, which are housed inside the containment element 20. The elongated conducting member 4 also comprises a filler 24 which has the function of spacing apart from each other the pipes 21 and the cables 22 and 23, and the pipes 21 and cables 22 and 23 from the inner face of the containment element 20. In variants not shown, the elongated conducting member 4 only comprises pipes configured to connect chemicals or other service fluids in the liquid state. In addition, where necessary, the containment element 20 of the elongated conducting member 4 is reinforced to meet structural requirements associated with installation and operating loads.

(17) With reference to FIG. 4, the stiffening element 16 is sleeve-shaped, extends around an axis A1, is mainly made of polymer material, and has a through-hole in the axis A1 with a substantially constant section; and a cylindrical wall 25 with a progressively increasing section along the axis A1 from left to right in FIG. 4 so as to have a differentiated flexibility along the axis A1. In practice, the flexibility of the stiffening element 16 increases along the A1 axis from right to left in FIG. 4.

(18) With reference to FIG. 5, the sleeve 9 extends along the axis A2, has two flared ends and a wall 26 of substantially constant thickness.

(19) In use, the system 1 for temporarily connecting the underwater station 2 is generally arranged in the resting configuration shown in FIG. 1. When it is indicated that it is necessary to transfer service fluids and/or energy and/or signals between the underwater station 2 and a surface facility 27, the surface facility 27 reaches the position indicated by the marker buoy 5 as better shown in FIG. 1. The surface facility is equipped with a lifting device 28, which recovers the cable 6 and lifts the elongated conducting member 4, which runs through the depth buoy 3. The head 19 of the elongated conducting member 4 is attached to a hooking structure 29 arranged on an edge of the surface facility 27 as shown in FIG. 7. In the operating configuration of FIG. 7, the head 19 of the elongated conducting member 4 is, for example, connected to a pumping device for chemicals or other service fluids in the liquid state arranged on board the surface facility 27 and/or to a generator or to a battery and/or to a device configured to exchange signals with the underwater station 2.

(20) Once the transfer is complete, the surface facility 27 and the lifting device 28 reposition the elongated conducting member 4 and the marker buoy 5 into the resting configuration shown in FIG. 1.

(21) The system 1 described with reference to FIGS. 1 to 7 is particularly beneficial for temporarily connecting a surface facility 27 and the underwater station 2 lying on the bed of a body of water in relatively deep water.

(22) If however the underwater station 2 is positioned on the bed of a body of water in relatively shallow waters it is convenient to use the system 30 shown in FIGS. 8 and 9. The system 30 differs from the system 1 described in FIGS. 1 to 7 in that the depth buoy 3 and its mooring line 7 are omitted and the head 19 of the elongated conducting member 4 rests on the bed of the body of water.

(23) In a further variant of the system 30 not shown in FIGS. 8 and 9, the cable 8, the sleeve 9 and the buoyancy modules 10 are omitted and, in the resting configuration, the elongated conducting member 4 is entirely supported on the bed of the body of water.

(24) With reference to FIGS. 10 and 11, the head 19 of the elongated conducting member 4 comprises an end structure 31, which is integral with the elongated conducting member 4; and a flange or mechanical connector 32 (FIG. 10), which is configured to be coupled to the end structure 31 and the cable 6. When the end structure 31 and the corresponding flange 32 are coupled together, they define a closed, generally hermetic, compartment inside which the free ends of the pipes and/or cables converge. These free ends are suitably sealed and protected.

(25) In the resting configuration shown in FIG. 10, the end structure 31 and the corresponding flange 32 are housed within the flared part of the sleeve 14 while, in the operating configuration of FIG. 11, the end structure 31 without a flange 32 is supported by the hooking structure 29 of the surface facility 27 and the pipes and/or cables are connected with the respective pipes and/or cables of the surface facility 27.

(26) It is clear that the present disclosure comprises further variants not explicitly described, without however departing from the protective scope of the following Claims. Accordingly, various changes and modifications to the presently disclosed embodiments will be apparent to those skilled in the art.