A method of removing a flexible line deployed between an offshore platform and a subsea structure, where the platform has a landing deck on which the flexible line is installed, the landing deck facing away from the platform towards an installation side. The method comprises: decoupling a topside end of the flexible line from the landing deck; lowering the topside end from the landing deck to the sea bed using a platform mounted winch, and detaching the winch from the topside end; moving the platform in a direction away from the installation side and positioning an installation vessel on the installation side; lowering a recovery line from the installation vessel and attaching an end of the recovery line to the topside or subsea end of the riser; raising the attached topside or subsea end onto the installation vessel from the seabed using the recovery line; and recovering the flexible line onto the installation vessel, whereupon the platform can be moved back to an operating position.

A rupture assembly that may be employed in the oilfield industry facilitates the deployment of a tubing string in a well. The rupture assembly may be installed at the bottom of the tubing string for the purpose of trapping air in a lateral section of the tubing, between the rupture assembly and an upper sealing assembly. As a result, the buoyant force in the lateral section reduces the drag encountered while running the tubing through the casing, thereby significantly reducing rig time, or permitting operations where none were possible previously. Once at landing depth, surface pressure may be added to burst and remove the seal and rupture assemblies.

A method for riser string handling on an offshore drilling vessel, the offshore drilling vessel including a multiple firing line hoist system, a riser tensioner system arranged in the second firing line, and a suspended riser transfer device. The method including the steps of lowering a riser string in the first firing line, and simultaneously assembling and preparing a riser tensioner system in the second firing line, wherein the riser hang-off assembly displaces the riser string, leaving the top end of the riser string exposed, from the first firing line to the second firing line to be connected to the riser tensioner system.

A riser assembly and method of installing a riser assembly are disclosed. The riser assembly includes a first attachment element connected to a first portion of flexible pipe and a second attachment element connected to a second portion of flexible pipe. The first attachment element and second attachment element are connected by at least one tether element, via a fixed structure in a configuration such that, in use, in response to movement of the first and second portions of flexible pipe, the tension load at any moment in time, at each attachment element, remains substantially equal.

A dual-BOP or multi-BOP self-standing riser configuration is disclosed, including at least a riser or another similarly fixed tubular structure disposed in communication with an associated drilling vessel and a subsurface well. The system supplements the traditional mud-line level BOP with one or more additional near-surface BOPs, which are tensioned using an adjustable buoyancy chamber rather than by means of a vessel-born tensioning device.

A riser or jumper assembly for transporting production, exportation or injection fluids is disclosed as is a method for providing buoyancy to such an assembly. The riser or jumper assembly includes a first segment of flexible pipe comprising a portion of flexible pipe body and a first and second end fitting, a further segment of flexible pipe comprising a portion of flexible pipe body and a first and second end fitting and an intermediate segment of flexible pipe comprising a portion of flexible pipe body and a first and second end fitting and at least one buoyancy element.

A method and apparatus for bundling flexible risers uses a vertically-hanging riser support shaft extending below the turret of a turret-moored FPSO to manage the motions of the risers. The risers may transition to a catenary configuration as they exit a bottom structure at the lower end of the riser support shaft and connect to wellheads or flowlines on the seafloor. Certain embodiments are suitable for use with a disconnectable buoyant turret mooring system while other embodiments may be used with spread-moored FPSOs.

A method for appraising a deepwater well comprising: producing a first quantity of hydrocarbon from an undersea reservoir; transporting the first quantity of hydrocarbon to a floating vessel; off loading the first quantity of hydrocarbon from the vessel; producing a second quantity of hydrocarbon from the undersea reservoir; and transporting the second quantity of hydrocarbon to the floating vessel.

A system and method for obstacle avoidance during hydrocarbon operations utilizing a non-vertical conduit between a vessel and associated subsea equipment. The system comprises a vessel and a conduit connected to the vessel with a first rotatable apparatus which is constructed and arranged to permit the vessel to rotate with respect to the conduit. The system also comprises a second rotatable apparatus connecting the conduit to subsea equipment secured to the seafloor. The second rotatable apparatus is constructed and arranged to permit the conduit to rotate with respect to the subsea equipment.

An intervention system and method for control of seabed equipment, including a control umbilical connected to a support vessel or rig via a surface winch; a tether connected to underwater seabed equipment; and an umbilical management system unit coupled between the tether and the control umbilical to couple the support vessel or rig to the seabed equipment. The control umbilical and the tether via the umbilical management system unit provide a communications channel for communicating media, including data, electrical power, hydraulic power and/or chemical treatment fluid, from the support vessel or rig to the seabed equipment. The umbilical management system unit allows for easy deployment and management of the control umbilical and tether and can reel in or pay out the tether and/or the control umbilical under remote control or autonomously.