Abstract: A method of installing a subsea structure, such as a hybrid riser tower, is disclosed. The riser tower includes a main portion and a buoyancy portion. When installed, the riser tower extends substantially from the seabed towards the surface with the buoyancy portion attached at a top end. The method includes taking the riser tower to an installation site in a substantially horizontal configuration with the main portion containing a first fluid and the buoyancy portion containing a second fluid, the second fluid being more dense than the first fluid. Then, tilting of the riser tower is performed such that it takes a substantially vertical configuration by allowing the first fluid in the elongate portion to interchange with the second fluid in the buoyancy portion. Also disclosed is a suitable apparatus for performing the method.

Abstract: 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.

Abstract: An offshore structure comprises a base configured to be secured to the sea floor. In addition, the offshore structure comprises an elongate stem having a longitudinal axis, a first end distal the base and a second end pivotally coupled to the base. Further, the offshore structure comprises an upper module coupled to the first end of the stem. The upper module includes a variable ballast chamber. Still further, the offshore structure comprises a first ballast control conduit in fluid communication with the variable ballast chamber of the upper module. The first ballast control conduit is configured to supply a gas to the variable ballast chamber of the upper module and vent the gas from the variable ballast chamber of the upper module. Moreover, the offshore structure comprises a deck mounted to the upper module.

Abstract: A method of installing marine equipment, the method including providing a marine apparatus comprising the marine equipment and a buoyancy device including at least a first and a second tank. The first tank containing air and the second tank containing a buoyant liquid having a specific gravity of less than 0.8 g/cm3. The method including providing a template on the seabed and guiding the marine apparatus down onto the template. Also a buoyancy device comprising at least a first and a second tank, the first tank containing a first fluid and the second tank containing a second fluid.

Abstract: A tension-legged offshore submerged platform, in hybrid concrete-steel solution, having a pre-stressed concrete central body, a steel peripheral structure, which is connected to the central body through steel stiffeners, and further to a basement for such a platform.

Abstract: A method and apparatus are described for containing an oil spill caused by a subsea blowout. In one embodiment, a blowout preventer (BOP) stack, located on a floor of an ocean, may be circumvented with a wall of a cylindrical containment assembly. At least one mud flap, located on the wall, may be activated to control the depth of the cylindrical containment assembly below the ocean floor. In another embodiment, the BOP stack may be circumvented with a hollow wall of a cylindrical containment assembly. The cylindrical containment assembly may be reinforced by filling the hollow wall with cement. A valve assembly may be positioned on a top perimeter of the reinforced wall. The valve assembly may comprise a hollow cavity. The valve assembly may be reinforced by filling the hollow cavity with cement.

Abstract: A method of assembling an offshore support system for use with a wind turbine. The method includes coupling a damper to a wind turbine tower. A counter-balance system is coupled to the damper for suspending at least a portion of the wind turbine above a water surface. The damper is positioned at least partially below a water surface to facilitate reducing movement of the wind turbine in at least one direction. The counter-balance system is positioned at least partially below the water surface to stabilize the wind turbine when subjected to wind and tidal forces.

Abstract: A floating energy generating device includes at least two wind turbines mounted on a floating open structure, the floating open structure being moored to the seabed with a mooring system, each wind turbine featuring in operation mode a blade and rotor part mounted at the top of a tower and being connected via a cable to a central control power electronic unit on the floating open structure, the central control power unit being connected to a submerged high voltage power export cable for exporting the electricity generated by the at least two windmills, characterized in that the floating open structure being connectable to or disconnectable from the mooring system and that when disconnected from the mooring system, the center of gravity of the floating open structure is at or below its center of buoyancy.

Abstract: To provide the auxiliary float of a floating structure which can prolong the lifetime of the floating structure by reducing external force acting on the brace and can be used even at very deep water by increasing buoyancy, and to provide a remodeling method of the floating structure. The auxiliary float (11) comprises two floats (12) coupled, respectively, to lower portions of two lower hulls (1) constituting a floating structure, two main coupling members (13) for coupling the floats (12) to each other, and four sub-coupling members (14) for coupling the main coupling member (13) and the float (12). The auxiliary float (11) is produced in advance and the floating structure is mounted on the auxiliary float (11), and then the lower hull (1) and the float (12) are connected, thus remodeling the floating structure.

Abstract: A method for providing a sustainable offshore community that includes a floatable, low cost platform structure which covers a large amount of real estate and is supported above the surface of the ocean from columns which pass through the structure such that the extremities of the structure are supported with stays that run from the top of the columns to the extremities of the platform. This type of staying structure permits the formation of the large floatable platform for supporting self sustaining communities by providing sizeable living and recreational areas, thus to permit an offshore community to exist at sea for a number of years.

Abstract: A method of locating a subsea structure beneath a floating deployment vessel for deployment to a seabed including at least the steps of: (a) transporting the subsea structure on a floating transporting vessel near to the deployment vessel; (b) lowering the transporting vessel to allow the subsea structure to float; (c) relocating either the transporting vessel or the subsea structure to allow the subsea structure to be separate of the transporting vessel; and (d) locating the subsea structure beneath the deployment vessel using one or more buoyancy elements with variable buoyancy.

Abstract: The Seafloor Power Station is one or more unmanned electric power generating Units (2) sending power to and operated from existing coastal sites by a manned facility (1) by connecting lines and hoses (3) delivering power to a grid by lines (4). Each Unit's hull (11) maintained in a vacuum, contains both nuclear steam and electricity generating systems. The hull functions as overpressure containment and as condenser in the event of a loss of coolant accident or other steam release. The Units operate submerged in very cold water, with depth set by remotely controlled vertical mooring systems, mounted on gravity mats (27). A Unit must be surfaced by its mooring system to refuel the reactor, an action both conspicuous and public, enabling international oversight of the fuel disposition.

Abstract: There is provided a method and apparatus for lowering and/or raising a load or structure to or from the bed of a body of water. The apparatus comprises a buoyancy apparatus configured to be coupled to a load, and having positive buoyancy sufficient to lift the load. At least one receptacle is provided on the apparatus for receiving a control weight lowered from a vessel to lower or raise the assembly. The lowering method includes forming an assembly from a buoyancy apparatus and a load and submerging the assembly to a position at a first height above the bed. In a preferred embodiment the assembly is submerged by a clump weight tow system. A control weight is deployed from a vessel to the assembly to overcome the positive buoyancy of the assembly and thereby lower the load from the first height to the bed. The raising method reverses the steps of the lowering method.

Abstract: An offshore station (1), in particular an offshore wind power station, comprises a floatable foundation (2) that can be sunk by flooding a hollow chamber, and a superstructure (6) on which functional units (7, 8) of the station (1) are arranged. The foundation (2) includes a bottom pale (3), a base (4) which is disposed on the bottom plate (3) and projects from the water surface (12) in the sunk state of the foundation (2) and on which the superstructure (6) can be mounted, and a floodable floating device (5) which surrounds the base (4) in the shape of a ring. In a method for building an offshore station (1), in particular an offshore wind power station, a floatable foundation (2) is prefabricated in a harbor zone, is towed to a mounting location after being prefabricated and is sunk, whereupon the station (1) is completed with a superstructure (6) and functional units (7, 8) of the station at the mounting location.

Abstract: 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. The exterior side walls of the polygonal 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 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.

Abstract: A stabilizing chamber to be used with a mobile offshore unit and a method of manufacturing and stabilizing therewith are disclosed. The stabilizing chamber includes a housing configured to removably receive and retain fluid therein, a first support, and a second support. The first and second supports are attached to the same side of the housing, and at least one of the supports is configured to support the weight of the stabilizing chamber. These supports are then configured to removably connect with the mobile offshore unit. The housing of the stabilizing chamber may be filled with fluid to at least partially submerge the stabilizing chamber. After fluid is received within the stabilizing chamber, the stabilizing chamber may be disconnected from the mobile offshore unit.

Abstract: A piling barge is disclosed by the present invention. In the piling barge disclosed, a supporting leg includes a supporting arm extended in vertical direction. Differing from the prior art, the supporting leg further includes a supporting base. The supporting base has a transverse section larger than that of the supporting arm, an end of the supporting arm is fixed with the upper surface of the supporting base. The supporting base of the supporting leg having a larger transverse section may receive support from a larger area of mollisol ground and thus provide a larger supporting force for the hull, which enables the piling barge to perform the piling operation on sea areas with mollisol ground. A piling device of the piling barge has pile frame adjusting mechanisms, such as a luffing oil cylinder, a luffing winch mechanism and a turntable, etc., which may adjust the incline angle and the position of the pile frame, therefore the working efficiency of piling operation of the piling barge can be improved.

Abstract: The invention relates to a supporting element (8) for an offshore wind turbine (3), comprising a base body (1) formed by a circular or polygonal basement (4), a shaft (5) with vertical walls and a plurality of vertical cavities (6) extending over the entire height thereof and a slab (2) dispose on the shaft (5) of the base body (1), on which slab (2) a wind turbine (3) is positioned and secured. The base body (1) of the supporting element (8) is produced using sliding formwork, from the basement (4) up to the upper base thereof.

Abstract: A floating wind turbine platform includes a floatation frame (105) that includes three columns (102, 103) that are coupled to each other with horizontal main beams (115). A wind turbine tower (111) is mounted above a tower support column (102) to simplify the system construction and improve the structural strength. The turbine blades (101) are coupled to a nacelle (125) that rotates on top of the tower (111). The turbine's gearbox generator and other electrical gear can be mounted either traditionally in the nacelle, or lower in the tower (111) or in the top of the tower-supporting column (102). The floatation frame (105) includes a water ballasting system that pumps water between the columns (102, 103) to keep the tower (111) in a 10 vertical alignment regardless of the wind speed. Water-entrapment plates (107) are mounted to the bottoms of the columns (102, 103) to minimize the rotational movement of the floatation frame (105) due to waves.

Abstract: The invention provides a method for the transport of a civil engineering structure in an aquatic medium. According to this method: at least one float is associated with the civil engineering structure in such a way as to ensure that the said civil engineering structure floats stably in an aquatic medium, the said float surrounding the civil engineering structure and a bottom portion of the civil engineering structure extending below the said float, and the civil engineering structure and the associated float are caused to move in the aquatic medium to a desired position.

Abstract: A semi-submersible structure. The hull includes four columns that are supported by two pontoons. The columns support the topsides and the topsides structural framing serves as horizontal framing between the columns. A truss frame is attached to the columns. The truss frame preferably includes heave plates. The truss frame extends downward below the pontoons a sufficient distance in the water such that it minimizes motions caused by environmental forces. The hull section and the truss space frame are constructed separately and assembled together at the offshore site where the structure is used for drilling and/or production.

Abstract: The present disclosure provides an improved method and system for loading a topsides onto an offshore structure by functional modules. A module support frame forms a supporting structure to which production modules can be assembled. The production modules are adapted to extract or process hydrocarbons from a hydrocarbon well in an offshore location. One production module is a well bay production module to which other production modules can be coupled, including a drilling support production module, separation production module, export module, and utility module. The module support frame can be loaded onto floating barges and other modules assembled thereto to allow the barges to provide incremental and controlled support during the loading process and for the floatover installation. The barges can be floated out to the offshore structure and loaded onto the offshore structure by methods including a floatover method or with a heavy-lift crane vessel.

Abstract: Method for installing a topside module on an offshore support structure that in use comprises at least one support leg that extends a height above the water level. The method comprises the steps of supporting said topside module on a barge in a position adjacent to said at least one support leg and de-ballasting the barge to lift the topside module a height above water level.

Abstract: A mounting system is disclosed for mounting structures and equipment, such as wind-electric generators on water. The structure is attached to a carrier, which is attached to a foundation through connecting elements. Buoyancy tanks or the inherent buoyancy of the carrier or the connecting elements are used to maintain a stable position of the carrier in the water. Utilizing connecting elements that transfer pushing and pulling forces, undesirable movements of the carrier are suppressed while requiring only moderate forces on the foundation.

Abstract: The present invention provides a method of creating a building structure to be installed on a basin floor wherein the base for erecting the structure would be an element of such a block and this block would be placed on the basin floor in such a way, and would be fixed in position relative to it in such a manner, that this base could be used as a foundation for stationary, large-sized heavy structures and also to ensure the possibility of using the block elements as members of the structure being erected and thus to increase the economic efficiency of the method.

Abstract: A stabilizing chamber to be used with a mobile offshore unit and a method of manufacturing and stabilizing therewith are disclosed. The stabilizing chamber includes a housing configured to removably receive and retain fluid therein, a first support, and a second support. The first and second supports are attached to the same side of the housing, and at least one of the supports is configured to support the weight of the stabilizing chamber. These supports are then configured to removably connect with the mobile offshore unit. The housing of the stabilizing chamber may be filled with fluid to at least partially submerge the stabilizing chamber. After fluid is received within the stabilizing chamber, the stabilizing chamber may be disconnected from the mobile offshore unit.

Abstract: Subsea oilfield equipment (2), such as an oil and/or gas production template, is installed at the water bottom (16) by means of a submerged installation vessel (1) from which hoisting lines (3A, 3B) are deployed to support the equipment during the installation procedure, which lines (3A,3B) are reeled from at least one hoisting line reeling winch (3A,3B) mounted at the submerged installation vessel (1) to lower the equipment (2) at a desired speed and in a substantially horizontal position onto the water bottom (16).

Abstract: 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.

Abstract: A method for making a deep draft semi-submersible drilling/production vessel having a center of gravity below its center of buoyancy by constructing a plurality of buoyant individual columns. The method connects a pair of columns with at least a first top truss and a first bottom truss. The method additionally floats a connected first and second columns horizontally in water. The method floats the semi-submersible structure to a location for installation. The method concludes by deballasting the semi-submersible structure with connected deck forming a semi submersible drilling/production vessel having a center of gravity below its center of buoyancy with a draft between 300 and 500 feet.

Abstract: Systems and methods for coupling a topside to a fixed or floating substructure during float-over installation of the topside are disclosed. Some system embodiments include a first plate coupled to a leg of the substructure and a retaining wall coupled to the first plate and extending substantially normally therefrom, wherein the retaining wall and the first plate form a recess. The system embodiments further include a second plate disposed at an end of a leg of the topside, the second plate received within the recess and engaging the first plate, and a plurality of shims disposed between the second plate and the retaining wall, wherein the plurality of shims are configured to inhibit translational movement of the second plate relative to the first plate.

Abstract: A quick-release system for coupling a topside for a fixed or floating platform and a barge for float-over installation of the topside is disclosed. The quick-release system comprises one or more releasable connections, each releasable connection configured to support at least a fraction of the weight of the barge and to be remotely actuated to allow the barge to decouple from the topside. In some embodiments, the quick-release system comprises two plates, one coupled to the topside and the other coupled to the barge, and a plurality of bolts extending therebetween. A frangible nut is coupled to each bolt. The quick-release system is actuatable by an electric signal that causes the frangible nuts to fracture and the barge to subsequently be released from the topside.

Abstract: A submersible and remotely-operable platform system for carrying out repeated operations in a submarine position, and producing electrical energy as either a primary or secondary purpose by means of one or more energy-conversion payload devices installed thereon. The platform and payload devices may be periodically brought to the surface and thence, if necessary, to a shore-based facility for maintenance or refit. In deployment, the platform is preferably engaged to its mooring lines and electrical cables while still on the surface. Simultaneous with controlled flooding of certain of its volumes, the platform is guided to an operational depth and attitude by the action of its winch assemblies upon their engaged mooring lines. Subsea currents energize the platform's payload of energy conversion devices, the electrical output being preferably conveyed via one or more surface-attached cables to an off-board facility for further processing, distribution, or consumption.

Abstract: A deepwater windpower plant (DWP) has a tension leg-type floating platform with an evacuable base for adjusting its buoyancy for installation at ocean depths ranging from 40 meters up to 1.5 kilometers and more. The DWP has a typical offshore wind turbine assembled close to shore which is then towed to a desired installation site on the ocean, and held in place by a gravity anchoring base (GAB), to which an evacuable portion or space of the DWP platform is anchored. The GAB has upwardly extending mooring tethers and a power cable which are brought to the ocean surface by attached buoys. The GAB is sunk to the ocean floor at the installation site under controlled conditions so that the GAB lands flat on the ocean floor. As the GAB sinks to the ocean floor, the mooring tethers and power cable are pulled to the surface by their respective buoys. The GAB is loaded with heavy ballast material that can be dropped from barges on the ocean surface into the upwardly open GAB below the barges.

Abstract: A floating lowering and lifting device (1) includes a floating structure (2) and a lifting unit (3) lowerable from the floating structure (2) towards the sea bed, the lifting unit (3) having a chamber (5) with at least one gas-inlet opening (9) in its wall (27) and an equalization opening (23, 25) in its wall (27), a gas supply (13) being connected to the gas inlet opening (9) The device includes a control element (15) connected to the gas supply (13) for controlling a gas supply rate to the chamber (5), wherein the chamber (5) includes a releasable coupling member (7) for releasably attaching to a load (8).

Abstract: 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.

Abstract: A spar-type offshore platform includes a buoyant upper hull structure supporting a deck and having lower end in which is received a buoyant lower mooring module. The upper hull structure is connected to the mooring module by connection lines. The upper hull structure is removed from the mooring module by disconnecting the connection lines from the upper hull structure while leaving the connection lines attached to the mooring module and while the mooring module remains moored to the seabed. The mooring module is lowered relative to the upper hull structure, allowing the latter to be moved away. The upper hull structure may be re-positioned over the mooring module, and the mooring module may be hauled upward into engagement with the lower end of the upper hull structure, so that the connection lines can be recovered and re-attached to the upper hull structure.

Abstract: A floating platform for recovery of oil and gas from offshore oil and gas fields includes a hull having a portion located substantially below the water surface, and including a portion thereof which extends above the water surface. The platform is anchored to the seabed by one or more tendons secured to the base of the hull and to the seabed. The payload capacity of the floating platform is increased without redesigning the structural design of the hull by attaching a column extension or mounting a detachable buoyancy module to the lower end of the hull for accommodating changing platform payload requirements.

Abstract: The present invention relates to a floating structure to receive maritime production or drilling installations that is provided with means to reduce movement caused by the action of environmental forces on it. These means confer a more stable behavior on the structure's movements.

Abstract: A temporary stability module and method for marine structures during construction, transportation and installation is taught. The device and method permit the structure, including platforms, deck and equipment to be constructed in an upright position, towed to an ocean installation site, and installed by ballasting the structure or temporary stability module and subsequent removal of the module.

Abstract: A semi-submersible offshore vessel including a rectangular ring-pontoon having a first transverse pontoon section at a first end of the vessel and a parallel second transverse pontoon section at a second end of the vessel, and two parallel pontoon sections extending between the first and the second end of the vessel. Four support columns extend upwardly from respective edge-portions of the ring-pontoon to support an upper deck structure. The first pontoon section has a vertical mean cross-section area (A) which exceeds the corresponding vertical mean cross-section area (B) of the second pontoon section, and the support columns in the second column pair each has a water-plane area (F) which exceeds the water-plane area (D) of each of the support columns in the first column pair.

Abstract: A bottom-supported jack-up rig has a hollow ring mat with a central opening for accommodating a lower portion of a hull nested therein when the rig is in transit. The ring mat has a predetermined surface footprint sufficient to provide stability to the rig when embedded in the sea bottom. The mat buoyancy helps support the hull and the legs in a floating position when the rig is in transit, while allowing lowering of the mat to the sea bottom without assistance of a ballasting/de-ballasting means.

Abstract: A method and a suitable arrangement for installation of a deck structure at an offshore location, where the deck structure is put on a vessel at a location inshore, then transported on the vessel to the offshore location and positioned relative to legs (13) of a jacket or gravity base type support structure standing on the sea bottom, or the legs or columns of a floating substructure, the deck structure having deck legs (5) corresponding to support legs (13) on the support structure, the deck legs (5) each being provided with a jack type of mechanism with an associated piston (1) which is extended into contact with and supported by the top part (3) of the corresponding support leg (13) at the beginning of a procedure for transferring the weight of the deck structure from the vessel to the support legs (13).

Abstract: This invention provides a method for installing a self-floating deck structure with at least one recessed cavity on the bottom of the self-floating deck structure onto a buoyant substructure. The self-floating deck structure is aligned over a submerged buoyant substructure and the top of the buoyant substructure is inserted into a recessed cavity in the self-floating deck structure until the buoyant substructure mates with the self-floating deck structure at a point above the water surface. The self-floating deck and the buoyant substructure are connected by welding or one or more mechanical device.

Abstract: Platform for drilling after or production of hydrocarbons at sea, consisting of a semi-submersible platform body which supports drilling and/or production equipment on its upper surface. The platform body is designed as a vertical mainly flat bottomed cylinder which is provided with at least one peripheral circular cut-out in the lower section of the cylinder since the centre of buoyancy for the submerged section of the platform is positioned lower than the centre of gravity of the platform.

Abstract: An extendable draft offshore oil and gas drilling and production platform (“EDP”) includes a buoyant deck having a central opening, an adjustably buoyant pontoon, and a single, adjustably buoyant column. The column is mounted upright on the pontoon, and is vertically movable through the central opening of the deck. The deck is supported on an upper end of the column above a body of water for offshore operations. The pontoon, and optionally, the column, have compartments with a buoyancy that is adjustable by pumps or sea water ballast and pressurized air. In one embodiment, the compartments can comprise a plurality of tubes. In another embodiment, a lower end of the column may comprise an open truss structure. The platform combines the advantages of a SPAR platform with those of a deep draft extendable draft platform.

Abstract: A floating offshore fluid storage caisson platform has a large diameter vertically oriented buoyant column or caisson, or multiple caissons, defining a storage chamber, and a telescopic keel tank disposed at the bottom end thereof, and may have deck on top of the caisson to support storage, drilling and production structures, equipment, and quarters. The structure can be transported horizontally either dry on a transporting vessel or towed with its keel tank in a fully retracted position. At the field of operation, the structure initially floats horizontally.

Abstract: A semi-submersible, multicolumn, deep draft, floating offshore oil and gas drilling and production platform comprises a floating hull having an adjustably buoyant base, a plurality of columns vertically upstanding from the base, and an equipment deck that is supported atop the columns when the platform is operationally deployed. Each of the columns comprises a cellular structure that includes a plurality of elongated tubes having a variety of cross-sectional shapes extending from the base to the top of the column. Each of the tubes defines one or more closed compartments. At least one of the compartments has a buoyancy that is fixed, and at least another one of the compartments has a buoyancy that is adjustable. The buoyancy of the compartments and the base can be controllably adjusted with pressurized air to provide a safer and less costly method for deploying the platform for offshore operations.

Abstract: A lateral mooring system for tendon-based platforms is disclosed, which provides reduced installation and/or operational cost associated with the installation and operation of an extended-base tension leg platform. The lateral mooring system includes a plurality of mooring lines that provide lateral support to the platform in mild metocean conditions, but may have application in more severe oceanic condition. A method for installing the system on the platform and a method for drilling wells on a offshore site.

Abstract: Jacket frame floating structures comprise one or more elongate vertical support columns formed of an open cross-braced jacket formwork of tubular members interconnected together and at least one cylindrical buoyancy capsule disposed in the open framework near an upper end and at least one cylindrical second buoyancy capsule near a lower end in vertically spaced relation. The buoyancy capsule(s) may be a single, or a plurality of upper and lower capsules bundled in circumferentially spaced relation with a central opening therethrough. Alternatively, a keel tank may replace the lower capsule.

Abstract: A marine buoy for the offshore support of subsea production and drilling activities that has a closed-bottomed base section with a solid ballast and variable ballast chambers, a chamber in the base section for storing equipment and supplies, and an upper section with a smaller cross-sectional area than the base section having an elevator shaft leading from the top of the upper section to the chamber in the base section. The upper section supports a deck for housing process equipment for operations that the marine buoy is supporting.