摘要:
An offshore floating production, storage, and off-loading vessel has a hull of generally cylindrical or polygonal configuration surrounding a central double tapered conical moon pool and contains water ballast and oil and/or liquefied gas storage compartments. An adjustable water ballast system induces heave, roll, pitch and surge motions of the vessel to dynamically position and maneuver the vessel. The moon pool shape and other devices on the vessel provide added virtual mass for increasing the natural period of the roll and heave modes, reducing dynamic amplification and resonance due to waves and vessel motion, and facilitate maneuvering the vessel. A disconnectable turret buoy at the bottom of the moon pool connects risers and mooring lines.
摘要:
A method for installing a water-submersible platform is disclosed. The method includes lowering the platform in water from a vessel positioned above the platform while spuds connecting the vessel to the platform stabilize the platform during lowering. An assembly of the vessel and platform, and a vessel that is used to connect to the platform is also disclosed.
摘要:
A submerged or partially submerged structure includes one or more non-cylindrical support columns interconnected at the lower ends thereof by horizontally disposed pontoons. The support columns include one or more strakes mounted thereon. The columns and strakes contribute to the stability of the structure during free floating operations and installation by reducing vortex induced motion.
摘要:
A spar-type offshore platform includes a buoyant upper hull structure having a lower end to which is detachably connected a buoyant lower module. A plurality of mooring line assemblies is connected to the lower module, the total weight of the mooring line assemblies being sufficient to sink the lower module. A method of separating the upper hull structure from the lower module includes disconnecting the lower module from the lower end of the upper hull structure, and then allowing the weight of the mooring line assemblies to sink the lower module.
摘要:
A tower structure (1) for use in a body of water, comprising a hollow outer section (2) with a first end (4) equipped with an opening. An inner section (3) is telescopically accommodated in the cavity of the outer section (2) and is telescopically movable in the outer section (2) from a position in which essentially the whole of the inner section is accommodated in the outer section to a position in which a length of the inner section projects above the first end of the outer section. The inner section comprises a plurality of chambers (6, 6′) fluid-connected via ducts (10′) and openings (9), and where at least one chamber is fluid-connected via at least one duct (10) to a source for a ballasting fluid (8), whereby the chambers (6) can selectively be filled with ballasting fluid.
摘要:
A spar platform for use in the offshore drilling or production of fossil fuels includes a hull having a centerwell. An airtight and watertight barrier traverses the centerwell, forming a variable buoyancy compartment in the centerwell. In certain embodiments the centerwell is open at the bottom to the sea, while in certain other embodiments the centerwell is sealed at the bottom. At least one sleeve for accommodating a riser extends through the barrier and the variable buoyancy compartment to the bottom of the centerwell. The sleeve has an open upper end to provide a drain for water accumulating in the centerwell, and it forms an airtight and watertight seal at its juncture with the barrier. In some embodiments, two or more airtight and watertight barriers are provided across the centerwell, defining an airtight and watertight fixed buoyancy chamber between each adjacent pair of barriers.
摘要:
An offshore floating production, storage, and off-loading vessel has a monolithic non ship-shaped hull of polygonal configuration surrounding a central double tapered conical moon pool and contains water ballast and oil storage compartments. The exterior side walls of the hull have flat surfaces and sharp corners to cut ice sheets, resist and break ice, and move ice pressure ridges away from the structure. An adjustable water ballast system induces heave, roll, pitch and surge motions of the vessel to dynamically position and maneuver the vessel to accomplish ice cutting, breaking and moving operations. The moon pool shape and other devices on the vessel provide added virtual mass capable of increasing the natural period of the roll and heave modes, reducing dynamic amplification and resonance due to waves and vessel motion, and facilitate maneuvering the vessel. The vessel may be moored by a disconnectable turret buoy received in a support frame at the bottom of the moon pool and to which flexible well risers and mooring lines are connected.
摘要:
An offshore system for petroleum production has a buoyant platform. A tendon assembly secures to the platform and extends down to a counterweight located near the lower end. A piling is embedded in the sea floor. A socket at the counterweight telescopingly slides over the upper end of the piling to prevent lateral movement of the platform. A dampening chamber is located between the socket and the piling. Ports for the chamber are arranged to allow a faster downward movement of the piling than upward movement.
摘要:
A method for deploying a floating platform includes storing buoys on a hull of the platform. Tension devices are mounted to the hull, each being connected by a line to one of the buoys. The operator tows the hull to a ballast down site while the buoys are stored on the hull. While adding ballast to the hull, the operator feeds out the lines from the tension devices at a selected tension. The hull moves downward in the water while the buoys float at the surface to maintain stability during the ballasting. The buoys are detached from the lines after the hull is ballasted to a desired depth.
摘要:
An offshore well platform is towed in an upright condition to a well site by the use of a temporary flotation device. The flotation device mounts to a portion of the platform and is partially submerged, increasing the ability and buoyancy of the platform. At the site, the engagement of the flotation device shifts to a deploying position. In the deploying position, the ballast of the platform is increased to cause it to more deeply submerge. The flotation device remains at least partially surrounding the platform and floating while the platform moves downwardly relative to it. This provides lateral support if needed to prevent heeling while being submerged. The flotation device is disengageable from the platform when the platform is fully submerged.