ES2264439T3 - PROCEDURE AND APPLIANCE TO INCREASE THE FLOATABILITY OF A FLOATING PLATFORM. - Google Patents

Abstract

Floating platform (10) comprising a hull (12) that supports one or more decks (14) in a body of water above the waterline, anchoring means that fix the hull (12) to the seabed, comprising said hull (12) buoyancy means intended to support said one or more decks (14) of said platform (10) above the waterline and pontoons (18) fixed at a lower end of said hull (12) , characterized in that it has supplementary buoyancy means (22) mounted on said hull (12) below the pontoons in order to increase the buoyancy of said platform (10).

Description

Procedure and apparatus to increase the buoyancy of a floating platform.

The present invention relates, in general, to floating platform systems for testing and production of hydrocarbon formations found in deep waters (600-10,000 feet / 182.9-3.048 m). Plus particularly, the invention relates to a method and system to change the buoyancy of the floating platform to support changes in platform payload and requirements for water depth without redesigning the hull of the platform.

Exploration for oil and gas deposits in deep water and the recovery of oil and gas is of high cost. Large capital expenditures are needed and therefore, only large oil and gas deposits justify Such disbursements. Smaller oil and gas deposits do not they usually justify large capital investments and therefore considers that they are not economical to produce.

Various procedures and production systems offshore have been used to locate and recover deposits from Oil and gas in deep water. Such production systems such as Mobile Offshore Drilling Units ("MODU") and Tendon Leg Converted Platforms (TLP) are often used in deep water. However, even these systems may be too costly. elevated for its manufacture and installation.

The document US-A-5,609,443 refers to a offshore platform that is adaptable between a towing mode and An operational mode. The document US-A-5,964,550 discloses a offshore platform with pontoons fixed at its end lower.

There is still a need for systems of enhanced platforms and drilling, particularly for use in deep water, which would justify economic investment to obtain oil and gas fields even relatively small. Drilling and production platforms, such as TLP platforms, are designed for use in marine environments particular and to support a maximum payload. The platform specifications are based on assumptions that they can prove, or not, be exact once the platform is installed and in use for a period of time. Other factors, such as the discovery of recoverable oil and gas from Adjacent deposits may modify payload requirements for a platform already in use. In this way, being able to increase the payload, a platform can support, without the need of a new helmet design, which would be very desirable and would reduce notably the cost of operating oil and gas deposits in high sea. Cost reductions can be obtained also eliminating the need to completely redesign the helmet and the platform node structure to support different payload requirements. The buoyancy of a floating platform can be increased by extending the column length of the platform instead of redesigning the helmet, which saves time and engineering expenses associated with the new design of the platform hull.

Therefore, an objective of the present invention is to present a floating platform adapted to withstand an increase in payload capacity without requiring redesign the structural design of the hull of the platform and in the that the increase in payload capacity can be admitted in the platform hull while at the manufacturing site.

Another objective of the invention is to make known a floating platform in which the payload capacity of the platform can be increased after the platform is located in the countryside. Said increase in payload capacity can be obtained by incorporating a buoyancy module to the hull of the platform instead of redesigning the node structure and the platform hull.

According to another aspect of the present invention, discloses a floating platform comprising a helmet that supports one or more decks in a body of water above the waterline, anchors that fix the hull to the seabed, said hull including buoyancy means to support said deck or more deck decks by above the waterline and pontoons fixed at one end bottom of said helmet, characterized by having means of supplementary buoyancy mounted on said hull below the pontoons to increase the buoyancy of said platform.

The floating platform provides oil and gas recovery from offshore oil and gas fields. The platform supports one or more decks above the water surface to support equipment for drilling and processing of oil, gas and water recovered from the oil and gas field. In a preferred embodiment, the platform comprises a case that has a part located substantially below the surface of the water and including a part that extends above the surface of the water. The platform hull includes a base and is anchored to the seabed by one or more tendons or cables attached to the base of the hull at one of its ends and to the seabed at opposite ends of the tendons. The payload support capacity of the platform is increased without the need to redesign the structural design of the platform hull by incorporating a column extension to the bottom of the silver hull.
shape.

According to another aspect of the present invention, discloses a procedure to increase load capacity Useful of a floating platform without redesigning the design structural hull of said platform, said being procedure characterized in that it presents the stage of fixing means of additional buoyancy provided under the pontoons fixed to a lower end of the hull of said platform.

For a better understanding of the invention and to illustrate how it can be done, then reference will be made, by way of example, to the attached drawings, in those who:

Figure 1 is a side view of a floating platform anchored in the seabed;

Figure 2 is a side view of the floating platform provided with an attached buoyancy extension to the bottom of the hull of the platform;

Figure 3 is a partial side view of another embodiment of the platform illustrating a module buoyancy mounted on the bottom of the hull of the platform;

Figure 4 is a plan view of the platform illustrated in Figure 3;

Figure 5 is a partial exploded view of a connection means to fix the buoyancy module to the hull of the platform; Y

Figure 6 is a side view of the platform illustrating a flow line support means or of riser mounted on the buoyancy module.

Referring first to Figure 1, the floating platform is designated, in general, by the reference numerical 10. Platform 10 comprises a center hull or column 12 that provides positive buoyancy and vertical support for platform 10. One or more decks 14 are supported on the hull 12 above the water surface 16. The equipment of drilling and / or production needed for recovery and oil, gas and water processing, recovered from the field of oil and gas, are fixed on deck 14.

The helmet 12 extends upwards from the hull base or keel 12. The hull base node 12 comprises pontoons 18 extending radially outward from the hull 12. Platform 10 is anchored to the seabed by tendons or fixing cables 20 attached, at one of its ends, to the pontoons 18 and at their opposite ends to foundation piles (no represented in the drawings) embedded in the seabed. He hull 12 provides sufficient buoyancy to support the load useful of platform 10, whose payload comprises cover 14, drilling and / or completion equipment, facilities production, production and drilling risers and a surplus buoyancy sufficient to develop the claim of the tendons or fixation cables.

Platform 10 is designed for environmental and deep conditions at the site in Deep water from an oil and gas tank of interest. In other sites, other platforms may be needed to efficiently recover oil and gas from others submarine deposits Such other platforms may be needed. to transport a higher payload than the load for whose support platform 10 is designed. However, the increased payload can be admitted by increasing the buoyancy of platform 10. A Increase in buoyancy can be done by extending the length of helmet 12 instead of redesigning the structural design of the structure of the hull and the base nodes of the platform 10. From analogously, the payload requirements for a platform may increase after installation, in which case you can mount a buoyancy module 32, as illustrated in Figure 3, in the lower part of helmet 12 of claim 10.

Referring below to Figure 2, the extension of column 22 is a cylindrical chamber relatively short that has an outside diameter approximately equal to the outer diameter of the hull 12. The column extension 22 is welded to the bottom of the hull 12 at welding 23 at the place of manufacture or construction of platform 10.

Referring below to Figure 3, another embodiment illustrates a buoyancy module 32 mounted on the bottom of the helmet 12. In the form of embodiment depicted in Figure 3, the buoyancy module 32 is added to marine platform 10 while it is located in the field to increase the payload capacity of platform 10 so that additional equipment can be installed on the deck of platform 10 or so that platform 10 can be install in a deeper water site. The module of buoyancy 32, such as column extension 22 represented in Figure 2 is a relatively short cylindrical chamber that It has a diameter approximately equal to the diameter of the hull 12. The mounting brackets 24 fix the module 32 to the hull 12. The mounting brackets 24 can be welded or in any other way attach to helmet 12 and module 32.

Alternatively, mounting brackets 24 are they can preinstall around the periphery of the helmet 12, by welding or other joining means, so that module 32 can be install at a later time after the platform 10 is anchored on the high seas, when required, to increase the payload capacity of the platform 10. The module buoyancy 32, depicted in Figure 3, is similarly provided with mounting bracket 26 to cooperate with the coupling with brackets 24 mounted on the hull 12. As shown more clearly in Figure 5, mounting brackets 24 are adapted to be received or coupled telescopically in the inside of the supports 26. Various joining means, such as grout, mechanical or welding connection elements, can be use to fix brackets 24 and 26 together and in this way, fix the buoyancy module 32 to the bottom of the hull 12. This form of bonding has the added advantage of allowing the module 32 is more easily separated from the hull 12 in the case of change the payload requirements of platform 10 and no longer buoyancy module 32 is needed or to replace a module greater in the event that greater buoyancy is required. Two o more modules 32 can also be connected in a cascade mode, in vertical alignment with the helmet 12 if necessary additional buoyancy

The extension of column 22 and the module buoyancy 32 may have the necessary piping system, comprising a filler hole 28 and a vent 30, for union with the ballast system of the platform 10. The devices additional riser tube pendants such as porches 33, for riser tubes or flow ducts 34, as shown in Figure 6, they can be installed in column extension 22 or in module 32, when required.

The shape of column extension 22 and the module 32 is illustrated as a closed cylinder or plug stopper for illustrative purposes It is to be understood that extension 22 and the module 32 may comprise several forms. If, for example, helmet 12 it comprises an opening from the cover to the bottom called "moon pool "(pool of the Moon '), extension 22 and module 32 they can be provided with an axial passage to adapt the alignment with the profile of the opening of the bottom of the pool of the moon. The extension 22 and module 32, in that arrangement, would have a toroidal shape or profile. Similarly, extension 22 and the module 32 may comprise radial extensions or arms that adapt the profile of pontoons 18, whose arms can be fixed to the bottom of pontoons 18.

Claims (7)

1. Floating platform (10) comprising a hull (12) that supports one or more decks (14) in a body of water above the waterline, anchoring means that fix the hull (12) to the seabed , said hull (12) comprising buoyancy means intended to support said one or more decks (14) of said platform (10) above the waterline and pontoons (18) fixed at a lower end of said hull ( 12), characterized in that it has supplementary buoyancy means (22) mounted on said hull (12) below the pontoons in order to increase the buoyancy of said platform (10). 2. Platform (10) according to claim 1, wherein said supplementary buoyancy means comprise a column extension (22) mounted at a lower end of said helmet (12). 3. Platform (10) according to claim 2, wherein said column extension (22) comprises a system of pipes for connection with the ballast system of said floating platform (10). 4. Platform (10) according to claim 1, wherein said supplementary buoyancy means comprise the minus a buoyancy module (32) mounted on said hull (12). 5. Platform (10) according to claim 4, comprising connection elements that fix removably said buoyancy module (32) to said hull (12). 6. Platform (10) according to claim 1, wherein said supplementary buoyancy means comprise support means on its peripheral surface to support one or more riser tubes or flow lines (34) attached to said platform
(10) 7. Procedure for increasing the payload capacity of a floating platform (10) without the need to redesign the structural design of the hull (12) of said platform (10), characterized in that it presents the stage of fixing the supplementary buoyancy means ( 18) provided below the pontoons (18) fixed at a lower end of the hull (12) of said platform (10).