Claims
- 1. A precast, modular spar system comprising:a. a cylindrical open-ended spar of relatively uniform cross section throughout its length and having a length such that its upper end extends above the water surface and its bottom end is subject to only minimal excitation forces caused by waves, said spar comprising a freeboard section, a buoyancy section, and a ballast section; b. a plurality of arcuate shaped segments having a middle tangential wall, at least two outer tangential walls, an outer radial wall, an inner radial wall, and a top slab; said segments adapted to be in a stacked relationship with an adjoining segment; c. said segments comprising said ballast section having a passageway extending through said top slab; d. an equalized pressure system for pressuring the spar throughout its length and to approximate the pressure of the sea water on the outside of the spar system, said equalized pressure system comprising a plurality of double walled equalized pressure pipes extending through said segments of said buoyancy section, a plurality of segmented water columns within said double walled pipes, means for injecting air into said segments; e. a moon pool open at the bottom and containing water non-excited by waves centrally extending the entire length of the spar and defined by inner radial walls of said sections.
- 2. The spar system of claim 1, further comprising a compression dome removeably attached to the bottom of said ballast section.
- 3. The spar system of claim 2, wherein said compression dome further comprises a plurality of ports into said moon pool.
- 4. The spar system of claim 1, further comprising at least one fill valve in said ballast section and at least one fill valve in said buoyancy section.
- 5. The spar system of claim 4, wherein said fill valves open to allow water to enter said ballast section and said buoyancy section to rotate said spar to a second vertical position offshore.
- 6. The spar system of claim 1, wherein said buoyancy section attaches to said freeboard section in a first horizontal assembly position and said ballast section attaches to said buoyancy section in said first horizontal assembly position.
- 7. The spar system of claim 6, wherein said first horizontal assembly position is onshore.
- 8. The spar system of claim 1, further comprising a platform deck secured to said freeboard section.
- 9. The spar system of claim 8, wherein said platform deck is a production deck supporting oil/gas production equipment.
- 10. The spar system of claim 9, further comprising means for transporting oil/gas between the sea floor and said production deck through said moon pool.
- 11. The spar system of claim 10, wherein said means for transporting oil/gas further comprises a riser system having riser pipes extending from said sea floor to said production deck through said moon pool.
- 12. The spar system of claim 1, further comprising means for anchoring said spar to the sea floor.
- 13. The spar system of claim 12, wherein said anchoring means further comprises a plurality of mooring lines attached to a plurality of mooring line storage reels at said freeboard section of said spar.
- 14. The spar system of claim 13, wherein said anchoring means further comprises transverse anchor lines.
- 15. The spar system of claim 1, wherein said buoyancy section having a weight adding dense material therein.
- 16. The spar system of claim 1, wherein said means for injecting air into said segments comprises at least one air inlet attached to said plurality of double walled pipes, a plurality of control tanks connected to said double walled pipes, and at least one air compressor attached to said control tanks.
Parent Case Info
This application claims benefit of Provisional Appln. Ser. No. 60/030,583 filed Nov. 12, 1996.
PCT Information
Filing Document |
Filing Date |
Country |
Kind |
102e Date |
371c Date |
PCT/US97/21053 |
|
WO |
00 |
5/12/1999 |
5/12/1999 |
Publishing Document |
Publishing Date |
Country |
Kind |
WO98/21415 |
5/22/1998 |
WO |
A |
US Referenced Citations (35)
Provisional Applications (1)
|
Number |
Date |
Country |
|
60/030583 |
Nov 1996 |
US |