Pipelines with a control system and forced circulation of fluids through the annulus between an inner barrier and an outer cover of a pipe use a system configured to force circulation of fluids through the annulus. The pipe includes segments (T1, T2, T3, TN) joined together by means of connectors, wherein each segment of the pipe has an injector pipe (I1, I2, I3, IN) for injecting fluid into the annulus at a first end of the segment, and a return pipe (R1, R2, R3, RN) for removing fluid from the annulus at a second end of the segment.

The present invention provides a buoyant system and method for a hydrocarbon offshore floating platform to be coupled and decoupled from a subsea buoyant extension with risers slidably coupled thereto. The buoyant system can allow rigid risers to be coupled and decoupled and alternatively move between a first elevation below the offshore floating platform, such as at the buoyant extension, and a higher second elevation at the offshore floating platform independent of a spool piece, arch support, and flexible joint for the risers. The buoyant system can reduce riser stress by reducing bending required for the riser to form a catenary or other curved shape even as a rigid riser.

A top interface for subsea riser on offshore, floating vessel has an upper funnel and a co-axial lower funnel in spaced-apart relation. Tension loads on the riser are reacted at the upper funnel while lateral and bending loads are reacted at the lower funnel. The riser top interface may be used with flexible risers or steel catenary risers.

A subsea flexible riser installation has a seabed foundation and a steep-configuration flexible riser anchored to the seabed by the foundation. An attachment formation is fixed relative to the riser and a locating formation is fixed relative to the foundation, both at positions elevated above the seabed. The locating formation is engaged with the attachment formation on the riser. This holds the attachment formation and the riser against movement when engaged, protecting the base of the riser from over-bending and fatigue.

An underwater steel catenary pipeline riser (SCR) lifting frame comprises a lift frame foundation and an SCR lifting frame comprising a lift frame interface adapted to be connected to the lift frame foundation; a foundation interface; a lift guide configured to accept the lift frame foundation; and a lift slidably disposed about the lift guide, the lift comprising an SCR pull head interface configured to be connected to an SCR pull head. The underwater steel catenary pipeline riser (SCR) lifting frame and systems using it allow for flex joint repair/replacement subsea which do not require large winches, deck re-enforcements, steering winches, and heavy crane lifts required by facility mounted winches above water and also reduces required heavy lifting and overall complexity of flex joint replacement.

A riser top connector assembly (20) is shown. The assembly (20) includes a first connector part (21) arranged on a flexible jumper prepared for connection with a second connector part (40) arranged on top of a marine riser tower assembly projecting from the seabed. The first connector part (21) is provided with suspension means adapted to engage with supporting means in order to be supported and be able to tilt in the marine riser tower assembly. The first connector part (21) includes a housing (22) that receives an extendable termination hub (23) having a clamp connector (24) attached thereto. The jumper termination hub (23) is alignable with a riser hub (44) on the second connector part (40) when the first connector part (21) is being tilted relative to the marine riser tower assembly.

The present invention provides a buoyant system and method for a hydrocarbon offshore floating platform to be coupled and decoupled from a subsea buoyant extension with risers slidably coupled thereto. The buoyant system can allow rigid risers to be coupled and decoupled and alternatively move between a first elevation below the offshore floating platform, such as at the buoyant extension, and a higher second elevation at the offshore floating platform independent of a spool piece, arch support, and flexible joint for the risers. The buoyant system can reduce riser stress by reducing bending required for the riser to form a catenary or other curved shape even as a rigid riser.

Obstructing fluid plugs are removed from a base section of a riser, which base section extends between a receiving end connected to an upright section of the riser and an emitting end of the riser connected to a subsea template located on a seabed over a drill hole to a subterranean void into which fluid received via the riser is to be injected from the subsea template (120). The obstructing fluid plugs are removed either by injecting heated assisting from a storage container into an injection point in the base section and injecting heated assisting liquid from the vessel in the upright section of the riser, or a heating unit is controlled to heat the base section to a predetermined temperature, and thereafter maintain a temperature level here above or equal to the predetermined temperature.

The invention proposes a method of modernizing a flexible conduit line (50), wherein the modernization method comprises the following steps performed in at least one end fittings joint (11, 12, 13), namely, removing a check valve (16) or a plug (17) from at least one outlet port (15) of an end fitting (111, 121, 131), removing a check valve (16) or a plug (17) of at least one outlet port (15) of an adjacent end fitting (111, 121, 131), installing a tubular line (90) in an external position to provide fluid communication between said at least one outlet port (15) of the end fitting (111, 121, 131) and said at least one outlet port (15) of the adjacent end fitting (111, 121, 131). The invention further proposes an end fittings joint (12) comprising an end fitting (121) and an adjacent end fitting (121), the end fittings joint (12) comprising a tubular line (90) positioned externally to the end fittings (121, 121) in order to establish fluid communication between at least one outlet port (15) of the end fitting and at least one outlet port (15) of the adjacent end fitting (121). The invention further proposes an interconnection module (80) connectable to a first end fitting (121) suitable to be installed in a first flexible conduit segment (52) and connectable to a second end fitting (121) suitable to be installed in a second flexible conduit segment (53). The interconnection module (80) further comprises a tubular line (90) in an external position configured to provide fluid communication between at least one outlet port (15) of the first end fitting (121) and at least one port (15) of the second end fitting (121).

Methods and systems are described for monitoring the integrity of a subsea pipeline network to transport the production fluid from a subsurface wellhead to surface facilities. More specifically, the described methods and systems are for monitoring the integrity of a riser pipe network and can include installing one or more inclinometers to the buoyancy tank and/or vertical riser structures.