초록

A buoyancy system includes a plurality of buoyancy joints distributed along a riser system. Each joint can include a riser pipe, an external frame disposed around a riser and a vessel, and a buoyant cladding disposed between the vessel and the frame.

대표청구항 ▼

What is claimed is: 1. A buoyancy joint configured to provide buoyancy for a riser system of an offshore platform, the buoyancy joint comprising: a) a riser section; b) a vessel, directly coupled to the riser section, configured to be pressurized with gas; c) an external frame, disposed around the

What is claimed is: 1. A buoyancy joint configured to provide buoyancy for a riser system of an offshore platform, the buoyancy joint comprising: a) a riser section; b) a vessel, directly coupled to the riser section, configured to be pressurized with gas; c) an external frame, disposed around the vessel; d) an enclosure, associated with the external frame and substantially enclosing the vessel, defining a space between the enclosure and the vessel; and e) a buoyant cladding, disposed in the space between the vessel and the enclosure. 2. A buoyancy joint in accordance with claim 1, wherein the enclosure includes a plurality of flat panels forming a rectilinear box. 3. A buoyancy joint in accordance with claim 2, wherein the flat panels include fiber reinforced plastic. 4. A buoyancy joint in accordance with claim 1, further comprising a plurality of buoyancy joints spaced-apart from one another and separated by other riser sections coupled between the buoyancy joints. 5. A buoyancy joint in accordance with claim 4, wherein the plurality of buoyancy joints has: a transportation configuration in which the plurality of buoyancy joints are bundled together; and an operational configuration in which the plurality of buoyancy joints are coupled along a riser system. 6. A buoyancy joint in accordance with claim 5, wherein the plurality of buoyancy joints are oriented horizontally in the transportation configuration. 7. A buoyancy joint in accordance with claim 5, wherein the plurality of buoyancy joints include end caps that have at least three linear sides that abut laterally to adjacent end caps of adjacent buoyancy joints in the transportation configuration. 8. A buoyancy joint in accordance with claim 4, wherein each of the plurality of buoyancy joints has a vessel with a diameter or length that is different from respective diameters or lengths of vessels of other buoyancy joints associated with the riser system. 9. A buoyancy joint in accordance with claim 1, wherein the enclosure forms a mold configured to receive an uncured foam material therein to form the buoyant cladding. 10. A buoyancy joint in accordance with claim 1, wherein: the vessel includes a fiber reinforced plastic; the buoyant cladding includes rigid foam; and the enclosure includes a fiber reinforced plastic. 11. A buoyancy joint in accordance with claim 1, wherein the buoyant cladding includes rigid foam substantially filling the space between the vessel and the enclosure. 12. A buoyancy joint in accordance with claim 1, wherein the vessel fills a majority of a volume defined by the external frame, and the cladding fills a minority of the volume with respect to the vessel. 13. A buoyancy joint in accordance with claim 1, wherein the vessel has an outer diameter that substantially equals an inner diameter of the enclosure. 14. A buoyancy joint in accordance with claim 1, wherein the external frame has a cross-sectional shape with respect to a longitudinal axis with at least three linear sides. 15. A buoyancy joint in accordance with claim 14, wherein the cross-sectional shape is selected from the group consisting of: square, rectangular, triangular, pentagonal, hexagonal, and octagonal. 16. A buoyancy joint in accordance with claim 14, wherein the vessel has a substantially circular cross-sectional shape with respect to the longitudinal axis. 17. A buoyancy joint in accordance with claim 1, wherein the vessel includes opposite, spaced-apart, hemispherical domes, each having an aperture through which the riser section extends, and seals formed between the riser section and the domes. 18. A buoyancy joint in accordance with claim 1, wherein the external frame includes: a pair of spaced apart end caps having an outer perimeter orthogonal to a longitudinal axis shaped with at least three linear sides; longitudinal members, extending between the end caps; lateral members, extending between the riser section and the outer perimeter; and a plurality of lift-eyes, attached to the frame, configured to allow for engaging and lifting the buoyancy joint. 19. A buoyancy joint in accordance with claim 1, wherein the external frame includes: means for intercoupling the external frame with other external frames of other buoyancy joints bundled together. 20. A buoyancy joint in accordance with claim 1, further comprising means for joining the riser section to other riser sections. 21. A buoyancy joint in accordance with claim 1, further comprising a pressurization tube extending into the vessel for pressuring the vessel. 22. A buoyancy joint configured to provide buoyancy for a riser system of an offshore platform, the buoyancy joint comprising: a) a riser section including an elongated pipe with a hollow therein configured to transport oil or gas; b) a vessel, directly coupled to and laterally surrounding the riser section, configured to be pressurized with gas; c) an external frame, disposed around the vessel; d) an enclosure, associated with the external frame and substantially enclosing the vessel, defining a space between the enclosure and the vessel; e) the enclosure including a plurality of flat panels; f) the external frame and the enclosure each having a cross-sectional shape with respect to a longitudinal axis with at least three linear sides; and g) a buoyant cladding, disposed in the space between the vessel and the enclosure. 23. A buoyancy joint in accordance with claim 22, further comprising a plurality of buoyancy joints spaced-apart from one another and separated by other riser sections coupled between the buoyancy joints. 24. A buoyancy joint in accordance with claim 23, wherein each of the plurality of buoyancy joints has a vessel with a diameter or length that is different from respective diameters or lengths of vessels of other buoyancy joints associated with the riser system. 25. A buoyancy joint in accordance with claim 23, wherein the plurality of buoyancy joints has: a transportation configuration in which the plurality of buoyancy joints are bundled together; and an operational configuration in which the plurality of buoyancy joints are coupled along a riser system. 26. A buoyancy joint in accordance with claim 25, wherein the plurality of buoyancy joints are oriented horizontally in the transportation configuration. 27. A buoyancy joint in accordance with claim 25, wherein the plurality of buoyancy joints include end caps that have at least three linear sides that abut laterally to adjacent end caps of adjacent buoyancy joints in the transportation configuration. 28. A buoyancy joint in accordance with claim 22, wherein the enclosure forms a mold configured to receive an uncured foam material therein to form the buoyant cladding. 29. A buoyancy joint in accordance with claim 22, wherein: the vessel includes a fiber reinforced plastic; the buoyant cladding includes rigid foam; and the enclosure includes a fiber reinforced plastic. 30. A buoyancy joint in accordance with claim 22, wherein the buoyant cladding includes rigid foam substantially filling the space between the vessel and the enclosure. 31. A buoyancy joint in accordance with claim 22, wherein the vessel fills a majority of a volume defined by the external frame, and the cladding fills a minority of the volume with respect to the vessel. 32. A buoyancy joint in accordance with claim 22, wherein the vessel has an outer diameter that substantially equals an inner diameter of the enclosure. 33. A buoyancy joint in accordance with claim 22, wherein the cross-sectional shape is selected from the group consisting of: square, rectangular, triangular, pentagonal, hexagonal, and octagonal. 34. A buoyancy joint in accordance with claim 22, wherein the vessel has a substantially circular cross-sectional shape with respect to the longitudinal axis. 35. A buoyancy joint in accordance with claim 22, wherein the vessel includes opposite, spaced-apart, hemispherical domes, each having an aperture through which the riser section extends, and seals formed between the riser section and the domes. 36. A buoyancy joint in accordance with claim 22, wherein the external frame includes: a pair of spaced apart end caps having an outer perimeter orthogonal to a longitudinal axis shaped with at least three linear sides; longitudinal members, extending between the end caps; lateral members, extending between the riser section and the outer perimeter; and a plurality of lift-eyes, attached to the frame, configured to allow for engaging and lifting the buoyancy joint. 37. A buoyancy joint in accordance with claim 22, wherein the external frame includes: means for intercoupling the external frame with other external frames of other buoyancy joints bundled together. 38. A buoyancy joint in accordance with claim 22, further comprising means for joining the riser section to other riser sections. 39. A buoyancy joint in accordance with claim 22, further comprising a pressurization tube extending into the vessel for pressuring the vessel. 40. A buoyancy system, comprising: a) an elongated riser system with a plurality of interconnected riser sections configured to be submerged and to extend between a floating platform and a wellhead; b) a plurality of buoyancy joints, operatively coupled in series with the riser sections of the riser system, each buoyancy joint including: i) a riser section; ii) a vessel, surrounding the riser section, configured to be pressurized, and including: a pair of opposite hemispherical domes, disposed at opposite ends of the vessel and each having an aperture through with the riser section extends; and a seal, disposed between the domes and the riser; iii) an external frame, surrounding the vessel, having a cross-sectional shape with respect to a longitudinal axis with at least three linear sides; iv) an enclosure associated with the external frame and substantially enclosing the vessel, defining a space between the enclosure and the vessel; and v) a buoyant cladding, disposed in the space between the vessel and the enclosure; and c) the plurality of buoyancy joints having: i) a transportation configuration in which the plurality of buoyancy joints are bundled together; and ii) an operational configuration in which the plurality of buoyancy joints are coupled along a riser system. 41. A buoyancy system in accordance with claim 40, wherein the buoyant cladding includes rigid foam substantially filling the space between the vessel and the enclosure. 42. A buoyancy system in accordance with claim 40, wherein the vessel fills a majority of a volume defined by the external frame, and the cladding fills a minority of the volume with respect to the vessel. 43. A buoyancy system in accordance with claim 40, wherein the vessel has an outer diameter that substantially equals an inner diameter of the enclosure. 44. A buoyancy system in accordance with claim 40, wherein the enclosure forms a mold configured to receive an uncured foam material therein to form the buoyant cladding. 45. A buoyancy system in accordance with claim 40, wherein the cross-sectional shape is selected from the group consisting of: square, rectangular, triangular, pentagonal, hexagonal, and octagonal. 46. A buoyancy system in accordance with claim 45, wherein the vessel has a substantially circular cross-sectional shape with respect to the longitudinal axis. 47. A buoyancy system in accordance with claim 40, wherein the external frame includes: a pair of spaced apart end caps having an outer perimeter orthogonal to a longitudinal axis shaped with the least three linear sides; longitudinal members, extending between the end caps; lateral members, extending between the riser section and the outer perimeter; and a plurality of lift-eyes, attached to the frame, configured to allow for engaging and lifting the buoyancy joint. 48. A buoyancy system in accordance with claim 40, wherein the external frame includes: means for intercoupling the external frame with other external frames of other buoyancy joints bundled together. 49. A buoyancy system in accordance with claim 40, wherein the plurality of buoyancy joints are oriented horizontally in the transportation configuration. 50. A buoyancy system in accordance with claim 40, wherein each of the plurality of buoyancy joints has a vessel with a diameter or length that is different from respective diameters or lengths of vessels of other buoyancy joints. 51. A buoyancy system in accordance with claim 40, further comprising a pressurization tube extending into the vessel for pressuring the vessel. 52. A buoyancy system in accordance with claim 40, wherein the plurality of buoyancy joints are distributed in series with a plurality of risers to form a length at least as long as 10,000 feet; and the individual buoyancy joints are sized to produce at least 50 kips net buoyancy. 53. A buoyancy system in accordance with claim 40, further comprising means for mitigating drag or vortex-induced vibration.