MXPA02008141A

MXPA02008141A - Method and apparatus for increasing floating platform buoyancy.

Info

Publication number: MXPA02008141A
Application number: MXPA02008141A
Authority: MX
Inventors: Earl Horne
Original assignee: Seahorse Equip Corp
Priority date: 2000-02-22
Filing date: 2001-02-22
Publication date: 2003-01-28
Also published as: WO2001062583A2; NO20023980L; AU3989101A; CA2400903A1; NO20023980D0; EP1259421A2; CA2400903C; AU2001239891B2; WO2001062583A3; BR0108589B1; EP1259421B1; EP1259421A4; NO332002B1; ES2264439T3; BR0108589A

Abstract

A floating platform for recovery of oil and gas from offshore oil and gas fields includes a hull having a portion located substantially below the water surface, and including a portion thereof which extends above the water surface. The platform is anchored to the seabed by one or more tendons secured to the base of the hull and the seabed. The playload capacity of the floating platform is increased without redesigning the structural design of the hull by attaching a column extension or mounting a detachable buoyancy module to the lower end of the hull for accomodating changing platform payload requirements.

Description

FACÉTO AND APPARATUS W INCREASE THE FLOTATION OF A FLOATING PLATFORM FIELD OF THE INVENTION The present invention relates, in general, to floating platform systems for analyzing and producing hydrocarbon formations found in deep offshore waters (183 to 3,049 meters (600 to 10,000 feet). More particularly, the invention relates to a method and system to change the flotation of the floating platform, to adjust the changes in platform loading and water depth requirements, without redesigning the hull of the platform.

BACKGROUND OF THE INVENTION The exploration of oil and gas deposits in waters located offshore, and the recovery of oil and gas from them, are very expensive. Large capital expenditures are required, and therefore only large oil and gas deposits justify such disbursements. Smaller oil and gas deposits usually do not justify large capital investments, and are therefore considered non-economic production.

REF .: 141502 Several methods and systems have been used for offshore production, in order to locate and recover offshore oil and gas deposits. Production systems such as the Mobile Seaborne Drilling Units ('MODU') and the Prestressed Steel Cable Platform (TLP) platforms are typically used in deep water, but these systems can also be manufactured and manufactured. quite expensive installation 10 There continues to be a need for improved drilling and platform systems, particularly for use in deep water, that justify the economic investment to produce relatively small oil and gas fields. drilling and production, such as TLPs are engineered to be used in particular offshore environments, and to withstand maximum load. The specifications for the platform are based on assumptions that can prove or not be accurate once the platform is installed and is in use for a period of time. Other factors, such as the discovery of oil and recoverable gas from adjacent deposits, can alter the load requirements for a platform that is already in use. In this way, it would be very desirable to be able to increase the load of a platform, without having to redesign the hull, and significantly reduce the cost to produce offshore oil and gas deposits. Cost reductions can also be achieved by eliminating the need to completely redesign the hull and the nodes structure of the platform, to adjust different load requirements. Floating a floating platform can be increased by extending the length of the platform column instead of redesigning the hull, saving time and costs for engineering design associated with the redesign of the hull of the platform. Therefore, an object of the present invention is to provide a floating platform adapted to support an increase in the load capacity, without redesigning the structural design of the hull of the platform. The increase in load capacity is adjusted by attaching a column extension to the lower end of the platform hull while in the manufacturing workshop. Another object of the present invention is to provide a floating platform, by which the load capacity of the platform can be increased after the platform is located in the production field. This increase in load capacity is provided by attaching a flotation module to the hull of the platform, instead of redesigning the hull and the node structure of the platform.

BRIEF DESCRIPTION OF THE INVENTION 5 The present invention provides a floating platform for recovering oil and gas from offshore oil and gas fields. The platform supports one or more support plates located above the water surface to accommodate equipment for the drilling and processing of oil, gas and water recovered from the oil and gas field. In a preferred embodiment, the platform includes a hull having a portion located substantially below the surface of the water, and includes a portion extending above the surface of the water. The hull of the platform includes a base and is anchored to the seabed by one or more prestressed steel cables, secured to the base of the hull, at one end thereof, and to the seabed at the ends opposite of prestressed steel cables. The load carrying capacity of the platform is increased without redesigning the structural design of the platform hull, joining a column extension to the bottom of the hull of the platform. 25 TO BRIEF DESCRIPTION OF THE DRAWINGS The manner in which the features, advantages and objects of the present invention, described above, are achieved can be understood in detail, wherein a more particular description of the invention was summarized briefly, above, with reference to the modalities of the same, which are illustrated in the attached drawings. However, the observation is made that the annexed drawings illustrate only typical embodiments of this invention and therefore should not be considered as limiting their scope, so that the invention can accept other equally effective modalities. Figure 1 is a side view of a floating platform anchored to the seabed; Figure 2 is a side view of the floating platform of the invention including a floating extension attached to the bottom of the hull of the platform; Figure 3 is a partial side view of an alternative embodiment of the platform of the invention, representing a float module mounted to the bottom of the hull of the platform; Figure 4 is a top plan view of the platform of the invention shown in Figure 3; Figure 5 is an exploded, partial view of the connector means for securing the flotation module of the invention to the hull of the platform; and, Figure 6 is a side view of the platform of the invention, illustrating support means of a flow line or rising tube, mounted on the flotation module of the invention.

DETAILED DESCRIPTION OF A PREFERRED MODALITY Referring first to Figure 1, the flotation platform of the invention is identified, in general, by the reference number 10. The platform 10 includes a central column or hull 12 that provides a positive float and vertical support for the platform 10. One or more support plates 14 are supported on the hull 12 above the surface of the water 16. Drilling and / or production equipment necessary for the recovery and processing of oil, gas and water recovered from the oil and gas field , are secured on the support plate 14. The helmet 12 extends upwards from the base or keel of the hull 12. The base node of the hull 12 includes pontoons 18 extending radially towards out from the hull 12. The platform 10 is anchored to the seabed by prestressed steel cables 20 secured at one end thereof to the pontoons 18, and at opposite ends thereof to the foundation piles (not shown in the drawings). drawings) embedded in the seabed. The hull 12 provides sufficient buoyancy to support the load of the platform 10, load including the support plate 14, the drilling and / or finishing equipment, the production facilities, the production and drilling risers, and a float excess, enough, to develop the pretension of the steel cables. The platform 10 is designed for the environmental conditions and depth in the place located offshore of a deposit, oil and gas, interest. In other places, other platforms may be required to efficiently recover oil and gas from other submarine deposits. Those other platforms may be required to support a greater load compared to the load that the platform 10 supports according to its design. The increased load, however, can be adjusted by increasing the flotation of platform 10. An increase in flotation can be achieved by extending the length of the hull 12, instead of redesigning the structural design of the hull and the structure of nodes of the base of the hull. the platform 10. Of equal In this manner, the loading requirements for a platform can be increased after the installation, in which case a flotation module 32 as shown in Figure 3 can be mounted on the bottom of the hull 12 of the platform 10. Referring now to Figure 2, the column extension 22 is a relatively short cylindrical chamber, having an outer diameter approximately equal to the outer diameter of the hull 12. The extension of column 22 is welded to the bottom of the hull 12. at the site of welding 23, at the place of manufacture or construction of the platform 10. Referring now to Figure 3, an alternative embodiment of the invention represents a flotation module 32 mounted to the bottom of the hull 12. In the embodiment of Figure 3, the flotation module 32 is added to the platform 10 for offshore, while it is located in the production field, to increase the loading capacity of the plat 10, so that additional equipment can be installed on the platform support plate 10 or such that the platform 10 can be installed in a deeper water site. The flotation module 32, like the column extension 22 shown in Figure 2, is a relatively short cylindrical chamber, having a diameter approximately equal to the diameter of the hull 12. Mounting posts 24 secure the module 32 to the hull 12. The mounting posts 24 can be welded, or otherwise fixed, to the hull 12 and to the module 32. Alternatively, the mounting posts 24 they can be pre-installed around the periphery of the hull 12, by welding or by other means of connection, such that the module 32 can be installed after the platform 10 is anchored offshore, as required, to increase the capacity of loading the platform 10. The flotation module 32, shown in Figure 3, is also provided with mounting posts 26 to cooperate in engagement with the posts 24 mounted on the hull 12. As more clearly shown in Figure 5 , the mounting posts 24 are adapted to be received or moved telescopically within the posts 26. Various connection means, such as cement grout, mechanical connectors or welding They can be used to immobilize the post 24 and 26 together and thus secure the flotation module 32 to the bottom of the hull 12. This way of connection has the added benefit of allowing the module 32 to be more easily disengaged from the hull 12 in the case that the loading requirements of the platform 10 change and that the flotation module 32 is no longer needed, or if it is necessary to replace a larger module in the case that a greater flotation is required. Two or more modules 32 may also be connected in a manner in which one is mounted directly on the other, in vertical alignment with the hull 12, in the event that additional float is required. The column extension 22 and the flotation module 32 can be provided with the necessary pipes, including a filling opening 28 and a vent 30, for connection to the ballast system of the platform 10. Hanging supports for the risers, additional, such as porches 33, for hanging the riser tubes or flow lines 34 therefrom, as shown in Fig. 6 can be installed on the column extension 22 or module 32, as required. The shape of the column extension 22 and of the module 32 is shown as a closed cylinder or plug, for illustrative purposes. It is understood that extension 22 and module 32 may comprise several forms. For example, if the hull 12 includes a lunar tank, the extension 22 and the module 32 can be provided with an axial conduit to match the alignment with the profile of the lunar pond. Extension 22 and module 32, in that arrangement, would have a shape or profile similar to a donut. Similarly, extension 22 and module 32 may include radial extensions or arms that coincide with the f of the pontoons 18, arms that can be secured to the bottom of the pontoons 18. Although one or more preferred embodiments of the invention have been presented and described, different and additional embodiments of the invention can be contemplated, without departing from the scope basic of the same, scope that is then determined by the following claims. It is noted that with regard to this date, the best method known to the applicant to bring the said invention to practice is that which is clear from the present description of the invention.

Claims

"% CLAIMS Having described the invention as above, the content of the following claims is claimed as property: 1. A floating platform that includes a hull that supports one or more supporting plates, in a body of water above the water level, and means of anchor securing the hull to the seabed, below the water level, characterized in that it includes the improvement which comprises flotation means secured to the lower end of the hull, to increase the flotation of the platform to support a greater load, or to operate in waters of greater depth, without redesigning the structural design of the hull.
2. The platform according to claim 1, characterized in that the flotation means comprises a column extension attached to the lower end of the hull.
3. The platform according to claim 2, characterized in that the column extension includes pipes for connection to the ballast system of the flotation platform.
4. The platform according to claim 1, characterized in that the flotation means it comprises at least one float module mounted on the lower end of the hull.
The platform according to claim 4, characterized in that one or more connectors are mounted on the periphery of the lower end of the hull and the flotation module, to secure the module to the hull.
The platform according to claim 4, characterized in that the connectors include cooperating connecting means for releasably attaching the flotation module to the hull.
The platform according to claim 2, characterized in that the column extension includes support means on the peripheral surface thereof, for supporting one or more ascending tubes or flow lines connected to the platform.
The platform according to claim 4, characterized in that the flotation module includes support means on the peripheral surface thereof, for supporting one or more riser tubes or flow lines connected to the flotation platform.
9. A method to increase the load capacity of a flotation platform, without redesigning the structural design of the hull of the platform, the method is characterized in that it includes the step of joining an extension on the lower end of the platform hull.
10. A method to increase the load capacity of a flotation platform, without redesigning the structural design of the hull of the platform, the method is characterized in that it includes the step of mounting a detachable floating module, on the lower end of the hull of the platform.