MXPA99001542A - Vessel turret systems - Google Patents

Abstract

A turret system is installed on an existing vessel (50) such as an oil tanker. A portion of the existing structure, such as the centre splice, is removed (B) to leave an opening (54). A support structure (55) is attached (C) within the opening (54). The support structure includes (D) a turret support means (56). The turret structure (57) is assembled (E) within the turret support means (56). Fluid piping is installed between the turret structure (57) and the pipework of the vessel, including a manifold structure (58) and a fluid swivel (20). The turret assembly is cladded (G, H) for environmental protection. In one arrangement, the turret system is within the profile of the original vessel. In another arrangement (not shown), the turret system is external to the profile of the original vessel.

Description

VESSEL TOWER SYSTEM DESCRIPTION OF THE INVENTION The present invention relates to a ship tower system, that is, a system that can be used in offshore terminals and that consists of vessels intended to provide fluid binding between the ship and the vertical pipes / underwater pipes. Previously, it had been proposed to convert a ship, like the oil tanker, into a floating production storage and unloading system (FADP), joining the assembly of a tower to one end of the ship, usually to the bow. The assembly of a tower includes a rotating fluid platform that allows a relative rotation, firstly, between the bottom of the sea and the associated vertical production pipes, the anchor chains, etc. and, secondly, the ship itself while maintaining a continuous flow path for the production of fluids from the subsea well to the ship. The previously proposed assembly of the ship's assembly is significantly outboard from the ship's end, which results in the assembly being exposed to the adverse effects of the environment and the need for a complex structural assembly attached to the parts. adequate loading-production of the ship's end. Consequently, once the tower assembly was placed, the conversion was permanent, or at least semi-permanent, in which case it would be necessary to remove the tower assembly. One of the objects of the invention is to provide such a ship tower system, which has a modular design and, therefore, can be easily placed on the deck of the oil tanker, or of another suitable vessel, and can also be removed with effort and minimum cost, so that the vessel can be reused for the purpose it originally had. According to a first aspect of the invention, there is provided a method of installing a tower system on an existing vessel, the method comprises the following steps: a part of one of the extremities of the existing structure of the vessel is removed, the part that is removed includes the outer shell; a support structure is attached to the exposed part of the vessel that remains after removing the part of the existing structure, the support structure includes support means for the tower and metal shell secured to the exposed part; joins the assembly of the tower to the support means of the tower of the support structure; A fluid tube is installed between the tower assembly and the ship's pipeline; and the assembly of the tower is covered for its environmental protection. According to a second aspect of the invention, a floating production storage and unloading vessel (FADP) is provided, which includes a tower system installed in a converted vessel, the FADP vessel comprises: a support structure subject to a - exposed part of the vessel that remains after removing a part of the existing structure that includes an external shell, the supporting structure includes the supporting means of the tower and a metal shell attached to the exposed part; a mounting of the tower attached to the support means of the tower; a fluid tube between the assembly of the tower and the ship's pipeline; and coating around the tower assembly for environmental protection. In a preferred embodiment, a frame structure can be attached to the top of the tower assembly, for the upper deck of the vessel. In one arrangement, the tower system is mounted externally at the original end of the vessel (bow), where the support structure includes extension structures, such as plates attached to the existing decks of the vessel, which forms extensions of the deck. It is also possible to provide vertical extension plates on each side of the deck extensions and to find horizontal stringers attached to the ship at different levels for deck extensions. Extension plates and stringers include the respective openings to accept and retain the tower assembly. In another provision, the tower system is mounted at least partially, preferably at least substantially, inside the contour of the original vessel. In the present arrangement, the central adjustment of the vessel is removed and a shell of longitudinal support structure is placed in its place. The lining of the tower is mounted to the shell of the support structure. Once the tower assembly is placed on the tower liner, a multiple structure is attached to the upper part of the tower liner and then a rotating fluid platform is installed on the multiple structure. The conversion of a ship like the tanker can be done easily using these techniques. The ship tower systems that result are strong and well protected against the effects of the environment. In addition, the modular structure of the conversion designs intends that, as the installation process is simplified, the tower systems can be easily removed so that the vessel is used again for the purpose it originally had. BRIEF DESCRIPTION OF THE DRAWINGS Next, the invention will be described by way of examples with reference to the accompanying drawings, throughout which like parts refer to similar references, and in which: Figure 1 is a sectional view schematic side of an externally mounted bow tower according to one embodiment of the invention; Figures 2A and 2B are schematic and planal side sectional views, respectively, of an integrated tower mounted in the bow according to another embodiment of the invention; Figure 3 is a general view of the ship and the tower of Figure 1 with details of the underwater pipeline and the anchor structure; and Figure 4 shows the construction steps followed during the conversion method from one ship to one equipped with the tower as shown in Figures 2A and 2B. With respect to Figure 1, it shows an external tower mounted on the bow consisting of two cylinders with concentric vertical axes, an outer cylinder 1 and an inner cylinder 2. The inner cylinder 2, which remains geostationary and is impermeable, supports the anchor chains 15 and the vertical pipes 16. Each chain 15 is stopped by a respective chain boom 21 which is located just below the upper part of the inner cylinder 2 of the tower. In order to accommodate the various angles of the chain, each chain 15 passes through a specially designed guide turtle 17, which projects below the bottom of the tower. The design of the center of the tower allows, with a ladder (not shown), it is possible to have complete access to it for maintenance and inspection. The integrated tower mounted on the bow of Figures IA and 2B is clearly similar with respect to the configuration of the tower assembly. In the arrangement of Figure 1, the central pipeline of the tower is arranged towards the bow of the Perpendicular Bow (PP) of the tanker and joins the existing structure of the vessel, as will be described below. In the arrangement of Figures 2A and 2B, the central pipeline of the tower is marginally at the stern of the PP of the tanker. In both cases, the multiple tower 3 has access at the level of the production deck 4, which is an extension of the second deck of the vessel. The extension of the end of the bow opens from the level of the production deck to the level of the upper cover 5. The upper cover 5 supports a frame structure 6 for environmental protection of the assembly of the turntable of the tower. This structure 6 has a shell coating, suitably reinforced to withstand the impact of the waves. The upper structure of the inner tube or cylinder 2 is hardened to resist the axial forces applied by the upper bearing 18. A rim of the upper structure 7 supports the outer ring of the upper bearing 18, as can be seen in the amplification of Figure 1. A support ring for the lower bearing 8 is designed to withstand the forces applied by the chains 15 to the guide vanes 17 and to the reactions of the bearing. A closure 9 of the bottom end of the tower is a hard plate designed to resist the hydrostatic head imposed by the movements of the boat as much as possible. It is also designed to support the forces imposed by the covers 10 of the vertical pipes. The covers 10 of the vertical pipes are connected to the upper covers to form an integrated structure. The upper deck is designed to be impermeable against flooding from the lower space. As can be seen in Figure 1, the tower is cantilevered towards the ship's bow. The tower forms a cylindrical cube around which the ship rotates by means of a bearing system. Said bearing system is formed by a three-roll upper bearing 18 which is located at the top of the tower, and a lower bearing 8 which is at the bottom of the tower. The deviations of the tower caused by the weight of the anchor are of an order of magnitude lower than those of the space between the inner cylinder 2 and the outer cylinder 1, so that a clogging will not occur. Preferably, the basic tower is placed between an extension of twelve strings or chains of catenary anchors 15, and has orientation towards the earth. The tower and the relative position of the ship produce a passive weather vane in extreme conditions, so that the behavior of the ship does not depend on the supply of energy nor on an up-and-running operation. Vertical flexible flow pipes or pipes 16, which transfer fluids from the bottom of the sea to the floating production storage and discharge tower (FADP), enter the tower structure through the bottom and continue towards the top of the tower. the tower by the covers 10 of the individual vertical pipes. The turntables 20, well known in this art, provide the transfer junction of the fluid between the pipe of the fixed tower and the vane of the ship.

The tower contains equipment to attach the chains of the anchors 15 to fix them in the bozas and hook the flexible vertical pipes 16. The tower consists of two cylinders with vertical axes, the outer cylinder 1 and the inner cylinder of 2.6 mo / d and 5.040m . o / d respectively, in a specific design. The outer cylinder 1 is 15,140m. long and internally hardened with ring hardeners. The inner cylinder 2, which remains geostationary and is impermeable, supports the twelve anchor chains 15 and the six vertical pipes 16. The central pipe of the tower is located towards the bow of the PP of the tanker for the tower mounted on the outer bow of Figure 1 and marginally rearward of the PP for the integrated tower of Figures 2A and 2B. In both cases, the tower is subject to the existing structure of the vessel using the reinforced armor typical of a ship. All vertical and horizontal armrests conform to the existing structure. The flange of the upper structure 7, which supports the outer ring of the upper bearing 18, is preferably welded to the shell of the frame of the inner tube by the total penetration of the weld. The lower bearing 8 supports the ring, which is designed to withstand the forces applied by the guide vanes 17 and the reactions of the bearing, preferably it is a forged part. Instead, it is possible to use a cross made of section I. The ring is welded to the shell of the frame by the total penetration of welds into circumferences. The chain boxes, which accommodate the chains 15, use the existing hardeners in the shell. These are coated on the inside to form boxes, which extend upwardly from the guide vanes 17 to the chain jackets 18. The chain vanes 18 are formed from two cylindrical cast iron attachments to the chain. Each boza 18 is placed in a seat. The arrangement is made so that the seals between the chain nozzles 18 prevent water leaking into the compartment during storms. The covers of the vertical pipes 10 are made of solid melted steel tubes. In addition to the function of protecting the vertical pipes 16 and the compartments inside the tower during the explosion, their structural strength allows them to be integrated into the interior cylinder structure. Such integration reduces the weight for the same force. The bottom of each cover of the vertical pipe 10 is widened to protect the vertical pipe 16 and help it to enter.

The guide tortoises 17 are of the curved type.

This transfers the load from the chain 15 via the contact tube to the prop of the curved shim bracket. A diver can unhook said shim and bring it to the surface for inspection. The curved fit of each guide turtle 17 has hoops (not shown) to hold the chain with low tension; the rings prevent the plate from being damaged. The upper structure of the inner cylinder 2 is hard to resist the axial forces that the upper bearing 18 applies. On the separation surface of the tower / ship of the outer tower of Figure 1, it is necessary to add a minimum hardening inside the outer tower. the bow of the ship. Modifications may include the installation of columns, reinforcements and vertical plates; these would be located towards the bow of the collision bulkhead. The cylinders of tower 1, 2 can be manufactured in several units, which are established according to the facilities and equipment of the manufacturer. The units in the form of the bearings 8, 18 at either end of the tower will be stressed with tension. After the installation of the tower structure on the vessel, the support structure of the upper and bottom bearings will be aligned and worked for a flat surface, to receive the bearings 8, 18. The inner and outer cylinders 2, 1 can then be assembled and coupled. Choice of installation of construction and availability of the vessel, will determine the process for manufacturing. The length of the ship's bow can either be installed on the ship as partial assemblies or in one piece. The two bearings 8, 18 incorporated in the design of the tower are designed to take all the expected loads and to ensure an easy rotation of the vessel around the anchors and the vertical pipes 16. The upper bearing 18 is placed on top of the the tubes of the primary tower. It is preferable one of three rollers, it is a variation of the standard commercial design available. The diameter can be approximately 5.81 meters. The upper bearing 18 is fixed to the forged parts of the rings, which, in turn, are welded to the structure of the tower. To ensure that there are no induced stresses in the structure, due to geometric variations, the bearing faces will be carefully worked after local structural welding and stress enhancement, before the final construction of the tower. The lower bearing 8 is located at the bottom of the inner cylinder 2 of the fixed tower. The same lower bearing 8 which is preferably made of a composite material is placed in twelve segments on the cylinder 2 with bolts and plates X 'with a slotted head. The bearing faces will be designed to transfer all loads to a forged hard-face reaction piece, incorporated into the outer cylinder 1 of the tower. These loads will be the radial components of all those loads described for the upper bearing 18. The composite material of the bearings for the lower bearing 8 is preferably manufactured with hot laminates and properly cured. The resulting material can be worked, is extremely dense and has a very good compressive strength, normally 414 N / mm2. It also has the remarkable advantage that it is lubricated only in seawater. Under these conditions, the coefficient of friction is virtually zero. The design of the lower bearing 8 can be such that it is possible to remove each segment separately for inspection and / or replacement. In Figure 3 you can see the anchors and vertical pipes typical for the system. The fluid transfer system has been designed to meet the following main requirements: (i) the tower will be mounted on the bow, external to the ship's structure in the case of the arrangement of Figure 1; (ii) the provision will allow the vessel to sail at 360 °; (iii) the tower is tied with the exterior 12, 152 mm diameter chain anchor ropes set in six pairs; and (iv) the arrangement will provide adequate vertical pipe trajectories and maximize vertical pipe spaces. Taking into account these requirements, the preferred tower incorporates the following characteristics. The anchor chains 15 are stopped in the tower via the guide vanes 17 that pass through individual mounds, which form the main vertical reinforcement of the inner cylinder 2 of the tower. The ends of the chain are locked with the inner chain bozas 18 which are located in the tower. The installation and tension of the chain is done using a wire rope that passes over a grooved sheave of the guide turtle (not shown) mounted on the upper section of the process deck, which converts the stern into a 150 lifts. tons.

This feature allows a simple installation procedure.

During the installation, the FADP vessel will turn in the direction of the berth and will be placed in position by means of towing chains. The tower will rotate and close in position against the boat to maintain the alignment of the montacárga and the broom. The geostationary cylindrical multiple structure 3 is mounted in a rotation ring; This structure stores the process equipment consisting of vertical pipe ESD valves, pad valves and non-return valves, carrying the produced oil, exporting gas, boosting the gas and injecting water into the production facilities. In order to reduce the number of flow paths of the rotating platforms, the three vertical production pipelines can end up in a production water chamber piped into the base of the rotating platform. In the field, the addition of pig iron is by means of a temporary cast iron addition projection located upstream of the vertical pipe ESD valve production. The addition of pig iron would be carried out during the proper state of the sea with the fixed tower and the shim of the bad weather of addition of pig iron, connected back to the pig iron addition system. Production fluids are transferred to the vessel through the assembly of the rotating platform 20.

The three-trajectory turntable assembly 20 is mounted on the geometrical center of the tower and provides the fluid path between the geofijos flow lines and those of fixed ships. The ESD and electrical control systems (not shown) are joined by means of slip rings to the central control room (SCC). The complete assembly of the tower is protected from the environment with a cover store that includes the frame structure 6; the back of the latter can be opened so that it finds free air ventilation. The access to the upper part of the tower, to the assembly of the rotating platform 20 and to the closing valves of the vertical pipe is by the upper deck 5 of the tanker. Now we will describe the way in which an existing vessel, such as the oil tanker, becomes a FADP, as shown in Figure 1. Initially, the bow area of the ship is cleared of all accessories. Parts of the ship's shell are removed from the areas where the assembled structure will be attached to it. It is then when several tension structures are placed on the existing decks of the ship to provide part of the assembled structure. For example, as shown in Figure 1, production deck 4 is an extension of the second deck of the ship. It is typical that, in general, the posterior horizontal extensions can be joined to other covers such as the upper cover. These extensions have openings to accept and retain the assembly of the tower. In general, the mounting structure may also include vertical extension structures on each side of the assembly, as well as horizontal stringers extending from the original contour 30 of the ship's bow. These extension structures can be manufactured from 25 mm steel plates. Then, the shell joins the extension structures where required and, once the tower assembly is installed, the multiple mounting 3, the mounting of the turntable 20 and the pipe, as well as the electrical connectors, can placed in the upper frame structure 6 that forms the house on deck. Figures 2A and 2B show an integrated FADP tower mounted on the bow, in which the assembly of the tower is similar to that of Figure 1 and, therefore, will not be described in detail. As will be explained below, the assembly of the tower is, in general, mounted at least partially inside the existing structure of the ship's bow, in contrast to the arrangement of Figure 1, in which it is provided an extension structure for the complete assembly of the tower. As can be seen in Figure 2A, the central pipe of tower C is located just aft of the ship's PP.

Figure 3 shows the typical layout for a FADP 40 vessel that includes anchoring and deployment of vertical pipes. Although the ship 40 is shown to be equipped with a tower structure according to Figure 1, a similar arrangement would be applied to one having a tower structure according to Figures 2A and 2B. In Figure 3, it can be seen that the chains of the anchor 15 adopt a catenary configuration when they are anchored to the bottom of the sea. Some of the flexible vertical pipes 16 may have a static configuration determined by several flotation modules 42 attached to the vertical pipes 16. In other cases, a half-buoy of water 44 which is maintained at the bottom of the sea by a heaped base frame 46, half water buoy 44 supports vertical pipe 16. Figure 4 shows the steps that are followed to convert a ship 40, such as an oil tanker, into a FADP tower ship, as shown in Figures 2A and 2B. In step A, the deck of the ship's forecastle 52 is cleared of all existing machinery and accessories. In step B, the central joint of the bow is removed and an opening 54 is left, which is generally rectangular in the deck of the bow lock 52 when viewed in the plane. In step C, the steel shell is attached to the interior of the opening 54, inclusive at the sides, and forms a longitudinal tower support structure 55. In step D, the lining of the tower 56, which is for including the assembly of the tower as already described above, is carried into the interior of the opening 54 and is attached to the lower decks 50 of the ship. In step E, the assembly of the tower 57 is constructed by installing an internal tower (or cylinder) and its bearings inside the tower liner 56. In step F, the multiple structure 58 (which includes a multiple assembly 3, as previously described) is placed on the liner 56 and the assembly 57 of the tower and secured. In step G, the assembly of the turntable 20 is installed on the multiple structure 58, as also happens with the pipeline and the necessary electrical and submarine connections. The liner 59 is added to enclose the upper structure of the tower including the multiple structure 58, and in the upper part is added an upper cover 60 that projects slightly from the bow lock 52 of the cover. In step H, the lining of the tower, the connection system and the commission is completed, including the addition of an upper frame structure 6 'which encloses the assembly of the rotating platform 20. Although the structures of the FADP tower of Figure 1 and Figures 2A and 2B have been described as mounted on the bow, as this is the preferred configuration, it is also possible to mount them on the stern. Also, although the conversion of an oil tanker is advantageous, since much of the existing infrastructure, such as tanks, pipes, etc., can be used with little or no modification for FADP purposes, it is possible to use any other vessel, either of own energy or towed. Thus, while the embodiments of the invention have been shown and described in detail to illustrate the application of the principles thereof, it should be understood that the invention may comprise other different modalities without departing from such principles.

Claims (30)

1. CLAIMS 1. A method of installing a tower system in an existing vessel, said method is characterized in that it comprises the following steps: removing a part of one of the ends of the existing structure of the vessel, the part that is removed includes the armor external; joining a support structure to the exposed part of the ship that remains after removing the part of the existing structure, the support structure includes means for supporting the tower and metal shell attached to the exposed part; joining a tower assembly to the support means of the tower of the support structure; install fluid tubes between the assembly of the tower and the ship's pipeline; and coat the tower assembly for its protection of the environment.
2. 2. The method according to claim 1, characterized in that it includes the step that consists in joining the structure of the frame to the upper part of the assembly of the tower.
3. 3. The method according to claim 2, characterized in that the structure of the frame is attached to the upper deck of the vessel.
4. 4. The method in accordance with the claim 1, claim 2 or claim 3, characterized in that the tower system is mounted on the outside of the original end of the ship.
5. 5. The method of compliance with the claim 4, characterized in that the outer shell is removed from the end of the vessel, and in that said support structure comprises a plurality of extension structures attached to the respective existing decks of the vessel, thereby forming the extensions of the cover.
6. 6. The method of compliance with the claim 5, characterized in that, generally, the structures of the vertical extensions are attached to the ship, on each side of the extensions of the cover.
7. 7. The method of compliance with the claim 5 or claim 6, characterized in that, in general, the horizontal stringers are attached to the ship at different levels to the extensions of the cover.
8. The method according to claim 5, claim 6 or claim 7, characterized in that the support means of the tower includes the respective openings for accepting and retaining the tower assembly.
9. The method according to claim 1, claim 2 or claim 3, characterized in that the tower system is mounted at least partially inside the existing vessel.
10. The method according to claim 9, characterized in that the tower system is mounted at least substantially inside the existing vessel.
11. The method according to claim 9 or claim 10, characterized in that the step of removing a part comprises removing the central link of the vessel at a predetermined distance from the end.
12. 12. The method according to claim 11, characterized in that when removing the central connection it leaves a substantially rectangular opening when viewed in the plane on the highest deck.
13. 13. The method according to the claim 11 or claim 12, characterized in that the metal shell is joined to the exposed part remaining after removing the central joint.
14. The method according to claim 13, characterized in that the back support structure includes a tower covering, which is mounted to the shell of the support structure.
15. The method according to claim 14, characterized in that, after the assembly t of the tower is placed on the lining thereof, a multiple structure is attached to the upper part of the ship's lining.
16. The method according to claim 15, characterized in that, after the multiple structure is joined to the tower lining, a rotating platform is installed on the multiple structure.
17. 17. The method according to any of the preceding claims, characterized in that the assembly of the tower is installed at the end of the ship's bow.
18. 18. A floating production storage and unloading vessel (FADP), includes a tower system installed in a converted vessel, the FADP vessel, characterized in that it comprises: a support structure attached to the exposed part of the ship that remains after removing a part of the existing structure that includes the external shell, the supporting structure includes support means of the tower and metal shell attached to the exposed part; a tower assembly attached to the tower support means; fluid tube between the assembly of the tower and the ship's pipeline; and coating around the tower assembly for environmental protection.
19. 19. The FADP vessel according to claim 18, characterized in that it comprises a frame structure attached to the upper part of the tower assembly.
20. 20. The FADP vessel according to claim 19, characterized in that the structure of the frame is attached to the upper deck of the vessel.
21. 21. The FADP vessel according to claim 18, claim 19 or claim 20, characterized in that the tower system is mounted on the outside of the original end of the vessel.
22. 22. The FADP vessel according to claim 21, characterized in that said supporting structure comprises a plurality of extension structures attached to the respective decks of the ship, whereby the extensions of the deck are formed.
23. 23. The FADP vessel according to claim 22, characterized in that said rear support structure generally comprises vertical extension structures attached to the ship on each side of the deck extensions.
24. 24. The FADP vessel according to claim 22 or claim 23, characterized in that said rear support structure comprises, in general, horizontal stringers attached to the ship at different levels to the extensions of the cover.
25. 25. The FADP vessel according to claim 22, claim 23 or claim 24, characterized in that the support means of the tower includes respective openings for accepting and retaining the tower assembly.
26. 26. The FADP vessel according to claim 18, claim 19 or claim 20, characterized in that the tower system is mounted at least partially inside the contour of the ship without converting.
27. 27. The FADP vessel according to claim 26, characterized in that the tower system is mounted at least substantially inside the existing vessel.
28. 28. The FADP vessel according to claim 26 or claim 27, characterized in that the tower system is mounted inside the central junction that is removed from the vessel.
29. 29. The FADP vessel according to claim 28, characterized in that the metal shell is attached to the exposed part of the ship that remains after removing the central joint.
30. 30. The FADP vessel according to claim 29, characterized in that the back support structure includes the cladding of the tower assembled to the shell of the support structure.