Claims
- 1. An extended-base tension leg platform substructure for an offshore platform comprising;at least three buoyant support columns disposed about a central axis of the substructure to form an opening centered about the central axis; a plurality of buoyant pontoons interconnecting at least some of the columns; and a plurality of wings or arms extending radially out from an outer perimeter of the substructure, each wing including at least one tendon connector affixed thereto, where the wings increase a radial extension of the substructure between about 10% and about 100%.
- 2. The substructure of claim 1, further comprising three columns triangularly disposed about the central axis.
- 3. The substructure of claim 2, wherein the wings extend radially from the columns.
- 4. The substructure of claim 1, further comprising four columns disposed about the central axis to form a quadrilateral.
- 5. The substructure of claim 4, wherein the quadrilateral is square, a rectangle or parallelogram.
- 6. The substructure of claim 5, wherein the quadrilateral is a square or rectangle.
- 7. The substructure of claim 6, wherein the wings extends radially from the columns.
- 8. The substructure of claim 6, wherein the wings comprise a closed structure, an open structure, or a mixture or combination of open parts and closed parts, and wherein the closed structures extends radially from the columns.
- 9. The substructure of claim 8, wherein the closed structure or closed parts are buoyant.
- 10. A platform structure comprising:a platform including a plurality of connecting members affixed to a bottom surface of the platform; a substructure for supporting the platform comprising: at least three buoyant support columns disposed about a central axis of the substructure to form an opening centered about the central axis, where the columns include a plurality of platform connectors for engaging the platform connecting members; a plurality of buoyant pontoons interconnecting at least some of the columns; and a plurality of wings or arms extending radially out from an outer perimeter of the substructure, each wing including at least one tendon connector affixed thereto, where the wings increase a radial extension of the substructure between about 10% and about 100%.
- 11. The substructure of claim 10, further comprising three columns triangularly disposed about the central axis.
- 12. The substructure of claim 11, wherein the wing extend radially from the columns.
- 13. The substructure of claim 10, further comprising four columns disposed about the central axis to form a quadrilateral.
- 14. The substructure of claim 13, wherein the quadrilateral is a square, rectangle or parallelogram.
- 15. The substructure of claim 14, wherein the quadrilateral is a square or rectangle.
- 16. The substructure of claim 15, wherein the wing extends radially from the columns.
- 17. The substructure of claim 10, wherein the wings comprise a closed structure, an open structure, or a mixture or combination of open parts and closed parts, and wherein the closed structures extends radially from the columns.
- 18. The substructure of claim 17, wherein the closed structure or closed parts are buoyant.
- 19. An extended-base tension leg platform comprising:a platform including a plurality of connecting members affixed to a bottom surface of the platform; a substructure for supporting the platform comprising: at least three buoyant support columns disposed about a central axis of the substructure to form an opening centered about the central axis, where the columns include a plurality of platform connectors for engaging the platform connecting members; a plurality of buoyant pontoons interconnecting at least some of the columns; and a plurality of wings or arms extending radially out from an outer perimeter of the substructure, each wing including at least one tendon connector affixed thereto, where the wings increase a radial extension of the substructure between about 10% and about 100%; a plurality of tendons attachably engaging at their top ends the tendon connectors on each wing at their top ends; and a plurality of seabed anchor connections attachably engaging the tendons at their bottom ends.
- 20. The substructure of claim 19, further comprising three columns triangularly disposed about the central axis.
- 21. The substructure of claim 20, wherein the wings extend radially from the columns.
- 22. The substructure of claim 19, further comprising four columns disposed about the central axis to form a quadrilateral.
- 23. The substructure of claim 22, wherein the quadrilateral is a square, rectangle or parallelogram.
- 24. The substructure of claim 23, wherein the quadrilateral is a square or rectangle.
- 25. The substructure of claim 19, wherein the wings extend radially from the columns.
- 26. The substructure of claim 25, wherein the wings comprise a closed structure, an open structure, or a mixture or combination of open parts and closed parts. and wherein the closed structures extends radially from the columns.
- 27. The substructure of claim 26, wherein the closed structure or closed parts are buoyant.
- 28. A method for improving fatigue life of subsea tendons mooring an leg platform comprising the steps of:forming a plurality of buoyant columns, interconnecting at least some of the columns with a plurality of generally horizontally disposed buoyant pontoons to form a substructure, attaching a plurality of arms about an outer perimeter of the substructure, the arms having a proximal end and a distal end, where the distal end includes a tendon porch, where the arms increase a radial extension of the substructure between about 10% and about 100%, securing one end of the tendons to the distal end of each of the arms, and securing the other end of the tendons to the seabed.
Parent Case Info
This application claims the benefit of U.S. Provisional Application No. 60/142,839, Jul. 8, 1999.
US Referenced Citations (18)
Foreign Referenced Citations (6)
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WO-9520074 |
Jul 1995 |
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Provisional Applications (1)
|
Number |
Date |
Country |
|
60/142839 |
Jul 1999 |
US |