초록 ▼

The present disclosure relates to an unmanned floating production unit (300) and method of installing a floating production unit comprising a deck structure (301) for mounting equipment for processing hydrocarbons, and a hull structure (302) formed from a first section (303) and a second section (30

The present disclosure relates to an unmanned floating production unit (300) and method of installing a floating production unit comprising a deck structure (301) for mounting equipment for processing hydrocarbons, and a hull structure (302) formed from a first section (303) and a second section (306), wherein the second section (306) is wider than the first section (303). The floating production unit (300) according to the present disclosure can provide a compact unit, which has dimensions which can lead to a heave natural period outside an area of significant wave energy, and as a result, it has substantially reduced and improved hydrodynamic responses. The floating production unit is configured to be small and lightweight, and can be fabricated, launched and towed to the installation site in two parts, without the requirement for heavy lifting or construction machinery, thus lowering manufacturing costs. In addition, the two parts of the floating production unit can be joined together at the installation site using a buoyancy and ballasting based technique. The floating production unit is designed to be unmanned during routine production operations, thus ensuring operating costs are low.

대표청구항 ▼

1. A floating production unit configured to be unmanned during normal production operations, the floating production unit comprising: a deck structure for mounting equipment for processing hydrocarbons; anda hull structure comprising:first section formed as a cylindrical like structure with a first

1. A floating production unit configured to be unmanned during normal production operations, the floating production unit comprising: a deck structure for mounting equipment for processing hydrocarbons; anda hull structure comprising:first section formed as a cylindrical like structure with a first diameter, the first section having a first ratio of the first diameter divided by a height of the first section, and a deck mounting portion formed in an upper part of the first section to which the deck structure is configured to be attached, a central axis of the first section being substantially perpendicular to a horizontal plane of the deck structure;a second section formed as a cylindrical like structure with a second diameter, the second diameter being configured to be between 1.1 and 2.5 times that of the first diameter, the second section having a second ratio of the second diameter divided by a height of the second section, the height of the second section being configured to be between 0.2 and 1.6 times that of the height of the first section, the second section being mounted below the first section and arranged such that a central axis of the second section aligns with the central axis of the first section, wherein the second section is configured when in use to be fully immersed; anda plurality of storage cells operable to store ballast when the floating production unit is in use, the ballast in the storage cells in cooperation with geometry of the hull structure providing a displacement to allow the floating production unit to float when in use to produce a heave natural period of the floating production unit corresponding to a period above which there is less than 15% of a total wave spectral energy in an extreme wave environment at an offshore location of the floating production unit. 2. A floating production unit as claimed in claim 1, wherein an immersed volume of the second section is configured to be between 0.2 and 3.5 times that of the immersed volume of the first section. 3. A floating production unit as claimed in claim 1, wherein the first ratio is configured to be between 0.2 and 2.5. 4. A floating production unit as claimed in claim 1, wherein the second ratio is configured to be between 1.0 and 8.0. 5. A floating production unit as claimed in claim 1, wherein the ballast comprises salt water, or high-density pumpable ballast with a specific gravity of 2 or more, or salt water and high density pumpable ballast with a specific gravity of two or more. 6. A floating production unit as claimed in claim 1, wherein the equipment for processing hydrocarbons which is mounted on the deck structure comprises equipment which is specified and configured for unmanned operations. 7. A floating production unit as claimed in claim 1, wherein the floating production unit further comprises a central access tube providing a conduit for risers and umbilicals between the production equipment on the deck structure and one or more subsea wells. 8. A floating production unit as claimed in claim 1, wherein the second section comprises an upper portion and a lower portion, the upper portion being closer to the first section than the lower portion, the storage cells being in the lower section and not extending to the upper section. 9. A floating production unit as claimed in claim 1, wherein the second section includes an air skirt for providing a recess in the second section for adjusting the buoyancy of the floating production unit, the recess being enclosed within the second section and defining a third diameter, the second diameter being greater than the third diameter. 10. A floating production unit as claimed in claim 1, further comprising at least one pump, or at least one compressor, or at least one pump and at least one compressor and one or more risers for exporting processed hydrocarbons. 11. A floating production unit as claimed in claim 1, wherein a draught of the hull structure and the deck structure of the floating production unit is configured to be no more than 5 meters at launch at their construction sites. 12. A floating production unit as claimed in claim 1, wherein a heave response of the floating production unit is configured to be above 15 seconds when in use. 13. A floating production unit as claimed in claim 1, wherein a cross section of at least one of the sections is substantially circular. 14. A floating production unit as claimed in claim 1, wherein a cross section of at least one of the sections is substantially oval. 15. A floating production unit as claimed in claim 1, wherein a cross section of at least one of the sections is substantially polygonal. 16. A floating production unit as claimed in claim 1, wherein the deck structure is buoyant. 17. A method of installing a floating production unit configured to be unmanned during normal production operations, the method comprising: fabricating, launching and towing a hull structure forming part of the floating production unit to an offshore site, the hull structure comprising:a first section formed as a cylindrical like structure comprising straight parallel sides providing the first section with a uniform cross section with a first diameter, the first section having a first ratio of the first diameter divided by a height of the first section, and a deck mounting portion formed in an upper part of the first section to which a deck structure for mounting equipment for processing hydrocarbons is attachable, a central axis of the first section being substantially perpendicular to a horizontal plane of the deck structure;a second section formed as a cylindrical like structure comprising straight parallel sides providing the second section with a uniform cross section with a second diameter, the second diameter being configured to be between 1.1 and 2.5 times that of the first diameter, the second section having a second ratio of the second diameter divided by a height of the second section the height of the second section being configured to be between 0.2 and 1.6 times that of the height of the first section, the second section being mounted below the first section and arranged such that a central axis of the second section aligns with the central axis of the first section, wherein the second section is configured when in use to be fully immersed; anda plurality of storage cells operable to store ballast when the floating production unit is in use, the hull structure providing a displacement to allow the floating production unit to float when in use, to produce a heave natural period of the floating production unit corresponding to a period above which there is less than 15% of a total wave spectral energy in an extreme wave environment at the offshore site of the floating production unit;mooring the hull structure to the sea bed;ballasting the hull structure such that the hull structure is at least partially submerged;fabricating, launching and towing the deck structure forming part of the floating production unit to the offshore site independently to the hull structure and such that the deck structure is positioned directly above the at least partially submerged hull structure;pulling the at least partially submerged hull structure towards the floating deck structure; connecting the hull structure to the deck structure to construct the floating production unit; andde-ballasting the floating production unit to an operational level. 18. A method as claimed in claim 17, wherein the launching and towing the hull structure further comprises using a sub-divided air cushion for buoyancy. 19. A method as claimed in claim 17, wherein the mooring the hull structure to the sea bed is performed by either a catenary mooring system, a semi-taught mooring system or a taught mooring system comprising a combination of a ground chain or wire section, a synthetic rope or wire mid-section and an upper chain or wire section. 20. A method as claimed in claim 17, wherein subsequent to the mooring the hull structure to the sea bed, the method further comprising installing a plurality of flexible flow-line risers and umbilical cables to connect the floating production unit to one or more subsea wells. 21. A method as claimed in claim 17, wherein the ballasting the hull structure further comprises using high-density pumpable ballast.