Patent Grant
8608408
The present embodiments generally relate to floating offshore oil and gas production and drilling facilities, but particularly those facilities with tension leg platform hull designs.
A need exists for a tension leg platform that can de-couple the need for setting optimized column to column spacing for deck support from the need to reduce deck steel weight and meet the stability requirements for pre-service conditions without temporary stability devices.
A further need exists for a tension leg platform that has tendon configurations in more efficient configurations to reduce the number of tendons and/or significantly save tendon weights.
Another need exists for a tension leg platform that has no temporary stability devices, or slanted columns for quayside integration and other pre-service conditions, and that uses conventional structural components with a conventional well bay.
A further need exists for a tension leg platform that has a specified column shape above the still water due to the latest revised metocean criteria, in more efficient configurations to reduce wave interactions and wave loads and thus reduce hull structure and tendon weights.
The present embodiments meet these needs.
The detailed description will be better understood in conjunction with the accompanying drawings as follows:
The present embodiments are detailed below with reference to the listed Figures.
Before explaining the present apparatus in detail, it is to be understood that the apparatus is not limited to the particular embodiments and that it can be practiced or carried out in various ways.
The present embodiments generally relate to tension leg platforms for use in offshore hydrocarbon production and drilling operations.
In one or more embodiments, the tension leg platform can include a plurality of column pairs. For example there can be from about 3 column pairs to about 6 column pairs.
Each column pair can include a primary column permanently coupled to a secondary column, and a plurality of primary pontoons can couple the primary columns to one another. Furthermore, each column pair can include a secondary pontoon located between the primary column and the secondary column thereof. The secondary pontoon can be used to connect the primary column to the secondary column. Each secondary column can have from about 2 tendons to about 6 tendons attached thereto.
The primary columns can be configured to support a deck. The deck can support drilling equipment, production equipment, or combinations thereof. The secondary columns can be coupled to the primary column below the draft of the tension leg platform.
The primary columns can include an upper portion and a lower portion. A transition portion can be disposed between the lower portion and upper portion. The lower portion can have a larger diameter than the upper portion. The upper portion of each primary column can be secured to the deck by 1 deck post and up to 4 deck posts.
One or more embodiments of the tension leg platform can include a first primary column. The first primary column can be coupled to a second primary column by a first primary pontoon. In addition, a third primary column can be connected to the second primary column by a second primary pontoon. The third primary column can also be connected to the first primary column by a third primary pontoon.
A first secondary column can be permanently coupled to the first primary column. A second secondary column can be permanently coupled to the second primary column, and a third secondary column can be permanently coupled to the third primary column.
A first secondary pontoon can be located between the first primary column and the first secondary column, a second secondary pontoon can be located between the second primary column and the second secondary column, and a third secondary pontoon can be located between the third primary column and the third secondary column.
In one or more embodiments a first primary column can be coupled to a secondary primary column by a first primary pontoon. In addition, a third primary column can be connected to the second primary column by a second primary pontoon. The third primary column can also be connected to the fourth primary column by a third primary pontoon. The fourth primary column can be connected to the fourth primary column by a fourth primary pontoon.
A first secondary column can be permanently coupled to the first primary column. A second secondary column can be permanently coupled to the second primary column, a third secondary column can be permanently coupled to the third primary column, and a fourth secondary column can be permanently coupled to the fourth primary column.
The second column can help meet quayside integration and stability requirements of tension leg platform pre-service conditions without considering temporary stability devices and/or slanted columns.
A first secondary pontoon can be located between the first primary column and the first secondary column, a second secondary pontoon can be located between the second primary column and the second secondary column, a third secondary pontoon can be located between the third primary column and the third secondary column, and a fourth secondary pontoon can be located between the fourth secondary column and the fourth primary column.
Each column pair can also include a connection member for coupling the upper portion of the secondary column to the primary column. The connection member can be a truss, a solid plate, perforated plate, or combinations thereof. The connection member can be welded, bolted, or otherwise secured to the adjacent primary column and secondary column.
Referring to
The deck 230 can support equipment 255, which can be similar to equipment described herein. The deck can be connected to the primary columns 211 by the deck posts 285. The deck posts 285 can be similar to one or more deck posts described herein. The primary columns 211 can include a primary column access shaft 295. The primary columns can include a lower portion 216, a transition portion 212, and an upper portion 214. The primary columns 211 can be configured to reduce the wave load experienced by the tension leg platform. The primary pontoons 250 can be similar to one or more pontoons disclosed herein.
The associated primary columns 211 and secondary columns 205 can form column pairs 210. The secondary columns 205, which can be similar to one or more secondary columns described herein and primary columns 211, can be permanently coupled to adjacent primary columns 211 by one or more connection members 280. The secondary columns 205 can be connected to the primary columns 211 below the water line 142. The secondary columns 205 can include secondary column access shaft 290. One or more tendons 209 can be connected to the secondary columns 205. One or more secondary pontoons 208, similar to one or more described herein, can be located between the primary columns 211 and the secondary columns 205.
Tendons 209 can be associated with the primary columns 211. For example, a first tendon or set of tendons can be secured to a first primary column, a second tendon or set of tendons can be secured to a second primary column, a third tendon or set of tendons can be secured to a third primary column, and a fourth tendon or set of tendons can be secured to a fourth primary column.
The tendons can be individual tendons, sets of tendons or groups of tendons.
The lower portion 216 can have a first diameter 320. The lower portion 216 can have a first height 360.
The transition portion 212 can transition the primary columns from the first diameter 320 to a second diameter 330. For example, the transition portion 212 can have an angle 310. The angle 310 can be from about 30 degrees to about 90 degrees. The transition portion 212 can have a second height 350.
The upper portion 214 can have the second diameter 330. The upper portion 214 can have a third height 340.
The second diameter 330 can be smaller to help reduce the impacts of overtopping. Overtopping discharge rate is a function of the first height 360, the second height 350, and the third height 340 as well as the second diameter 330. As such, the more the second diameter 330 is reduced the greater reduction in overtopping. This Figure also shows the water line 142.
The second diameter 330 can be smaller to help reduce the extreme wave loads. Extreme wave particle velocity distribution along the primary columns above mean water level is highly nonlinear. The wave crest particle velocities are significantly higher than those at mean water level. Wave loads are proportional to particle velocity square and projected area. As such, nonlinear high-frequency extreme wave loads can be reduced by 50 percent or more. The tendon responses are sensitive to the wave high-frequency excitations and may cause well-known “ringing” phenomena which will impact tendon strength and fatigue dramatically. With specified shape of primary columns, tendon extreme dynamic responses can be reduced significantly.
The second diameter 330 can be smaller to help reduce the extreme wave diffractions. Extreme waves passing the primary columns will be more transparent with less wave crest enhancements which help to reduce column freeboard to meet the minimum airgap requirements. As such, the hull structural weight will be reduced and tension leg platform pre-service stability will be benefited.
Due to hydrodynamic interactions between primary column and secondary column, tension leg platform surge/sway Response Amplitude Operators (RAOs) around fatigue periods can be optimized and improved. Thus, fatigue life of Steel Catenary Risers (SCRs) attached can be improved significantly.
Due to hydrodynamic interactions between primary column and secondary column, tendon tension Response Amplitude Operators (RAOs) around fatigue periods can be optimized and improved. Thus, tendon fatigue life can be improved significantly.
The deck 230 can support equipment 255. The equipment 255 can be used for hydrocarbon production, drilling, or combinations thereof. Illustrative equipment can include mud pumps, derricks, boilers, generators, and the like.
The column pairs 210 can include a primary column 211. The primary column 211 can be coupled to a secondary column 205. For example, a connection member 280 can be used to permanently connect the primary column 211 to the secondary column 205. The secondary column 205 can be connected to the primary column 211 below the water line 142. The secondary column can have one or more tendons 209 connected thereto. The primary column 211 and the secondary column 205 can have a cylindrical shape, rectangular shape, square shape, or other shape.
The columns pairs 210 can also include a secondary pontoon 208 located between the primary column 211 and the secondary column 205. The secondary pontoon 208 can have any shape. For example, the secondary pontoon can be square, rectangular, cylindrical, or another shape.
The primary pontoons 250 can connect columns adjacent thereto to one another. For example, the primary pontoons 250 can connect to one column adjacent a left portion thereof and to another column adjacent to a right portion thereof. The primary pontoons can have any shape. For example, the primary pontoons can be square, rectangular, cylindrical, or another shape.
One or more deck posts 285 can secure the deck 230 to the primary columns 211. The deck posts 285 can be tubular, angle iron, c-channel, or the like.
While these embodiments have been described with emphasis on the embodiments, it should be understood that within the scope of the appended claims, the embodiments might be practiced other than as specifically described herein.
The present application claims priority to and the benefit of U.S. Provisional Patent Application Ser. No. 61/292,279 filed on Jan. 5, 2010, entitled “Secondary Column Enhanced Tension Leg Platform With Specified Upper Column Shape”, which is incorporated herein in its entirety.
| Number | Name | Date | Kind |
|---|---|---|---|
| 3976021 | Blenkarn et al. | Aug 1976 | A |
| 3986471 | Haselton | Oct 1976 | A |
| 3996755 | Kalinowski | Dec 1976 | A |
| 4909174 | Bowes | Mar 1990 | A |
| 4987846 | Yamashita et al. | Jan 1991 | A |
| 6447208 | Huang et al. | Sep 2002 | B1 |
| 6503023 | Huang et al. | Jan 2003 | B2 |
| 7033115 | Huang et al. | Apr 2006 | B2 |
| 20030113170 | Huang et al. | Jun 2003 | A1 |
| 20090114139 | Zou | May 2009 | A1 |
| Number | Date | Country | |
|---|---|---|---|
| 61292279 | Jan 2010 | US |
