Offshore apparatus and method
An offshore platform for use in combination with an offshore rig comprises an upper deck defining an upper deck aperture which is alignable with a rig aperture of the offshore rig, when said offshore rig extends over the upper deck, to permit objects to extend between the offshore rig and through the upper deck. The offshore platform further includes a sheath arrangement aligned with the upper deck aperture and extending upwardly relative to the upper deck to be alignable with the rig aperture, wherein the sheath arrangement defines a confinement zone for confining objects which pass downwardly from the offshore rig through the rig aperture.
1. An offshore platform for use in combination with an offshore rig, comprising:
an upper deck defining a first upper deck aperture, the first upper deck aperture being alignable with a first rig aperture of the offshore rig by displacing the offshore ring to extend over the upper deck, whereby objects become permitted to extend between the offshore rig and through the upper deck; and
a first sheath arrangement aligned with the first upper deck aperture and extending upwardly relative to the upper deck to be alignable with the first rig aperture, wherein the sheath arrangement defines a first confinement zone for confining objects which pass downwardly from the offshore rig through the first rig aperture.
2. The offshore platform according to claim 1 , wherein the offshore platform is an offshore wellhead platform configured to accommodate an upper terminating end of at least one well.
3. The offshore platform according to claim 2 , wherein the terminating upper end of the at least one well is alignable with the first upper deck aperture.
4. The offshore platform according to claim 1 , wherein the first sheath arrangement circumscribes the first upper deck aperture.
5. The offshore platform according to claim 1 , wherein the first sheath arrangement extends upwardly from the level of the upper deck.
6. The offshore platform according to claim 1 , wherein the first sheath arrangement is securable around a peripheral region of the first upper deck aperture.
7. The offshore platform according to claim 1 , wherein the first sheath arrangement is securable around a peripheral region of the first rig aperture.
8. The offshore platform according to claim 1 , wherein the first sheath arrangement extends through the first upper deck aperture.
9. The offshore platform according to claim 1 , wherein the first sheath arrangement extends through the first rig aperture.
10. The offshore platform according to claim 1 , wherein at least a portion of the first sheath arrangement is rigid.
11. The offshore platform according to claim 1 , wherein at least a portion of the first sheath arrangement is flexible to define a sheath curtain.
12. The offshore platform according to claim 1 , wherein at least a portion of the first sheath arrangement is supported by at least one of the upper deck and the offshore rig.
13. The offshore platform according to claim 1 , wherein at least a portion of the first sheath arrangement is at least one of:
extended from the offshore rig during deployment of the first sheath arrangement; and
extended from the offshore platform and upwardly towards the offshore rig during deployment of the first sheath arrangement.
14. The offshore platform according to claim 1 , wherein the first sheath arrangement comprises a hoisting support arrangement.
15. The offshore platform according to claim 1 , wherein the first sheath arrangement comprises a first component connected or mounted to the offshore platform, and a second component connected or mounted to the offshore rig.
16. The offshore platform according to claim 1 , wherein the first sheath arrangement comprises a compliant portion.
17. The offshore platform according to claim 1 , wherein the first sheath arrangement is telescopic.
18. The offshore platform according to claim 1 , wherein the first sheath arrangement extends downwardly relative to the upper deck towards a first lower deck to define a lower confinement zone for confining objects passing between the upper and first lower decks.
19. The offshore platform according to claim 18 , wherein the first sheath arrangement defines an upper sheath portion extending upwardly relative to the upper deck and a lower sheath portion extending downwardly relative to the upper deck.
20. The offshore platform according to claim 1 wherein the offshore rig comprises a cantilever portion which is extendable over the upper deck of the offshore platform, the cantilever portion defining the first rig aperture.
21. The offshore platform according to claim 1 , wherein the upper deck defines a second upper deck aperture which is alignable with a second rig aperture of the offshore rig, when said offshore rig extends over the upper deck, to permit objects to extend between the offshore rig and through the upper deck.
22. The offshore platform according to claim 21 , comprising a second sheath arrangement aligned with the second upper deck aperture and extending upwardly relative to the upper deck to be alignable with the second rig aperture, wherein the second sheath arrangement defines a second confinement zone for confining objects which pass downwardly from the offshore rig through the second rig aperture.
23. A method for confining objects extending between an offshore platform and an offshore rig which extends over an upper deck of the offshore platform such that an upper deck aperture of the offshore platform is alignable with a rig aperture of the offshore rig by displacing the offshore rig to extend over the upper deck, the method comprising:
extending a sheath arrangement between the upper deck of the offshore platform and the offshore rig such that the sheath arrangement is aligned with the upper deck aperture and the rig aperture and defines a confinement zone for confining objects which pass downwardly from the offshore rig through the rig aperture.
24. An offshore platform for use in combination with an offshore rig, comprising:
an upper deck defining a first upper deck aperture which is alignable with a first rig aperture of the offshore rig when said offshore rig extends over the upper deck, to permit objects to extend between the offshore rig and through the upper deck; and
a first sheath arrangement aligned with the first upper deck aperture and extending upwardly relative to the upper deck to be alignable with the first rig aperture, wherein the sheath arrangement defines a first confinement zone for confining objects which pass downwardly from the offshore rig through the first rig aperture, wherein the offshore rig defines a first drill center and the first rig aperture is provided on the first drill center such that the first drill center is positionable within the first confinement zone defined by the first sheath.
25. The offshore platform according to claim 24 , wherein the offshore platform accommodates multiple wells arranged in a cluster.
26. The offshore platform according to claim 25 , wherein the upper end of at least one of the multiple wells is moveable to be selectively aligned and misaligned with the first drill center of the offshore rig.
27. An offshore system, comprising:
an offshore platform having an upper deck defining an upper deck aperture;
an offshore rig having a rig aperture, wherein the offshore rig is extendable over the upper deck of the offshore platform by displacing the offshore rig to align the rig aperture with the upper deck aperture and permit objects to extend between the offshore rig and through the upper deck; and
a sheath arrangement extendable between the upper deck of the offshore platform and the offshore rig such that the sheath arrangement is aligned with the upper deck aperture and the rig aperture and defines a confinement zone for confining objects which pass downwardly from the offshore rig through the rig aperture.