A well intervention monohull vessel and method of use including a tower type open derrick structure disposed on a deck of the vessel and a sole point land out having a sole point of riser tension contact with a top of the derrick structure. The vessel may also include subsea equipment such as an intervention riser system and an emergency disconnect package, a moon pool door preferably capable of transporting the subsea equipment, an intervention lift frame, a surface coiled tubing reel, a riser storage area, a rail, a pallet, a subsea tree, a crane, and/or drawworks.

An offshore drilling rig includes a drill deck, at least one primary well center and a diverter system arranged below the primary well center, a drilling support structure extending upwardly from the drill deck and above the primary well center and the other work center and a first and a second hoisting system supported by the drilling support structure and being adapted for raising or lowering a first and a second load carrier, respectively, and where the offshore drilling rig includes a positioning system adapted for selectively positioning at least the first load carrier in at least a first or a second horizontal position different from the first horizontal position, where the first load carrier in the first horizontal position is positioned above the primary well center, and in the second horizontal position is positioned above the other work center.

An offshore drilling vessel includes a floating hull subjected to heave motion. The hull includes a moonpool and a drilling tower near the moonpool. A drilling tubulars storage rack is provided for storage of drilling tubulars. The vessel includes a heave motion compensation support that is adapted to support a slip device whilst performing heave compensation motion relative to the heaving motion of the vessel. A racking device is provided with a heave motion synchronization system that is adapted to bring a tubular retrieved from the storage rack in heave motion into a vertical motion that is synchronous with the heave compensation motion of the string slip device. The racking device includes vertical rails and at least two separate motion arm assemblies mounted on said vertical rails. Each separate motion arm assembly includes its own vertical drive which is electrically connected to the heave motion synchronization system.

A method for offshore dual-drive core drilling with three layers of casings under surge compensation is provided. According to the method, a drilling vessel is located at set latitude and longitude coordinates by a dynamic positioning system; drill pipes are stabilized by a seabed template; torques and drilling pressures can be transmitted during drilling of the casings by means of surge compensation of the casings at a wellhead; during drilling for sampling, the surge compensation can compensate to a certain extent for a change in water depth caused by rising or falling tides, or surge, thereby preventing the casings from colliding with equipment and ensuring the safety of wellhead operation; and the drilling of three layers of casings is achieved by means of dual driver heads to effectively protect a wellbore wall, such that high core-drilling rate and good core-drilling quality are achieved during drilling for sampling.

This invention relates to a drilling rig or a drill ship having a first activity centre with a main well, a second activity centre with an auxiliary well and a third activity centre with offline casing and drill pipe stand-building capabilities. The offline casing and drill pipe stand-building facility is a standalone feature and can be located in the forward or aft side of a drilling rig or drill ship depending on the choice of the builder or operator.

A method for offshore dual-drive core drilling with three layers of casings under surge compensation is provided. According to the method, a drilling vessel is located at set latitude and longitude coordinates by a dynamic positioning system; drill pipes are stabilized by a seabed template; torques and drilling pressures can be transmitted during drilling of the casings by means of surge compensation of the casings at a wellhead; during drilling for sampling, the surge compensation can compensate to a certain extent for a change in water depth caused by rising or falling tides, or surge, thereby preventing the casings from colliding with equipment and ensuring the safety of wellhead operation; and the drilling of three layers of casings is achieved by means of dual driver heads to effectively protect a wellbore wall, such that high core-drilling rate and good core-drilling quality are achieved during drilling for sampling.

A method for assembly of a riser string onboard a vessel for performing subsea wellbore related operations involving said riser string, the riser string extending between a subsea wellbore and the vessel in a wellbore related operation, wherein the vessel includes a hull, a riser storage storing therein, in horizontal orientation, multiple pre-assembled riser stands and/or multiple individual riser stand, a deck structure having an elongated transfer opening above said riser storage, a transfer elevator, wherein multiple pre-assembled riser stands, each being pre-assembled from multiple riser sections connected end-to-end and each having a length of at least 150 ft. (45.72 m), and/or multiple individual riser sections each having a length of at least 150 ft. (45.72 m), are stored, in said horizontal orientation, in the riser storage.

An offshore drilling vessel includes a floating hull subjected to heave motion. The hull includes a moonpool and a drilling tower near the moonpool. A drilling tubulars storage rack is provided for storage of drilling tubulars. The vessel includes a heave motion compensation support that is adapted to support a slip device whilst performing heave compensation motion relative to the heaving motion of the vessel. A racking device is provided with a heave motion synchronization system that is adapted to bring a tubular retrieved from the storage rack in heave motion into a vertical motion that is synchronous with the heave compensation motion of the string slip device. The racking device includes vertical rails and at least two separate motion arm assemblies mounted on said vertical rails. Each separate motion arm assembly includes its own vertical drive which is electrically connected to the heave motion synchronization system.

A continuous vertical tubular handling and hoisting buoyant structure has a hull, a main deck, an upper neck extending downwardly from the main deck, an upper frustoconical side section, an intermediate neck, a lower neck that extends from the intermediate neck, an ellipsoidal keel and a fin-shaped appendage secured to a lower and an outer portion of the exterior of the ellipsoid keel. The upper frustoconical side section is located below the upper neck and maintained to be above a water line for a transport depth and partially below the water line for an operational depth of the buoyant structure. An automated stand building system mounted to the hull is in communication with a controller and configured to make up the marine risers, make up casing, and make up drill pipe.

An offshore drilling vessel including a hull having a moonpool, a bow and a stern, an accommodation topside having crew quarters and a bridge, said accommodation topside being arranged on the hull at the bow, a main deck between the accommodation topside and the stern of the vessel, wherein a front main deck portion of the main deck extends forward of the moonpool and a rear main deck portion of the main deck extends rearward of the moonpool, a firing line hoist system mounted on the hull at said moonpool, including a drilling structure, a hoisting device supported by the drilling structure and having a load attachment device displaceable along a firing line, the hoisting device including one or more cables and one or more associated winches to manipulate the position of the load attachment device relative to the drilling structure, one or more pivotal burner booms, each burner boom having an inner portion pivotally mounted at a lateral side of the hull and an outer portion supporting a burner, the burner boom being pivotable between a storage position generally parallel to the side of the hull and an operative position wherein the boom is directed away from the hull, the burner boom in the storage position being lower than the level of the main deck.