A novel configuration of lightly tensioned or substantially untensioned, i.e. substantially compliant mini-riser is provided to facilitate coiled tubing and/or wireline interventions in rigid catenary riser installations. Those can include in particular clearing hydrates that may accidentally plug risers or subsea pipelines connected to those risers. Existing Intervention Y units can be used, or they can be modified to suit design condition of particular installations.

The mini-riser can be used with flexible joint hang-offs, Titanium Stress Joint hang-offs or with novel Spoolflex hang-offs.

A clamp for a flexible pipe is provided that provide a load bearing flange on the flexible pipe permitting buoyancy jackets to be joined thereto. The clamp has a longitudinal axis arranged to extend along the length of the flexible pipe and a radial axis being perpendicular to the longitudinal axis. The clamp includes: a plurality of separate clamp elements being supported together in a radial array extending at least partially around the longitudinal axis; engagement means located between neighboring clamp elements to movably interconnect the clamp elements; and a strap being adapted to surround the clamp elements, in use for exerting a compressive force thereon. Also provided is a clamp element for use in the aforementioned clamp.

A flexible elongate element for installation in a body of water to extend between a seabed connection device and a unit arranged at the opposite end of the flexible elongate element. At least one lateral displacement device is connected to a portion of the flexible elongate element and configured to displace at least a portion of the flexible elongate element a lateral distance away from a first axis extending between the seabed connection device and the unit, the at least one lateral displacement device including a spring member. The flexible elongate element may be a flexible riser, umbilical, hose, or cable.

A riser assembly and method of supporting a riser assembly are disclosed. The riser assembly includes a riser; at least one buoyancy compensating element attached to the riser; and at least one damped biasing element for controlling movement of the riser about a neutral position with respect to an adjacent underwater structure. The biasing element is directly or indirectly connected to the riser and is directly or indirectly connectable to the adjacent underwater structure.

The present disclosure provides a system and method for supporting a catenary riser coupled to an offshore platform system including a pull tube and a pull tube stress joint for girth weld stress reduction and improved fatigue performance. A pull tube sleeve is coupled around a welded connection of the pull tube. The sleeve has a larger inner diameter than an outer diameter of the pull tube to form an annular space therebetween, and a fill material is filled into the space between the sleeve and the pull tube. The fill material provides a supportive coupling between the sleeve and the pull tube. The sleeve, the pull tube, or both can have gripping surfaces formed in or on their surfaces to retain the fill material in the space. The sleeve can be formed from a plurality of portions and be welded, fastened, or otherwise coupled around the pull tube.

An arrangement of an umbilical of data communication lines and/or electrical energy transmission lines is mounted on a lazy wave catenary riser. The umbilical has a first section extending from an upper hang off location of the riser continuously downward to a first installation point at the riser and a second section extending from a second installation point at the riser continuously downward to the sea bed at a riser touch down location. The first installation point is positioned in an installation region of the riser between a lowest sag bend point and a highest hog bend point of the lazy wave catenary riser extension. The first 1 section is tensioned to a flatter catenary shape than a catenary shape of the riser between the upper hang off location and the first installation point, so that a portion of the first section extends detached from the riser.

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.

Disclosed are high strength tubular devices for use in oil and gas well drilling and completions, oil and gas well intervention, and/or production systems. The high strength tubular devices include a pipe component and a secondary layer on the surface of the pipe component. The secondary layer can be either a continuous or partial layer and includes a nanostructured alloy. Alloy compositions are disclosed. Methods for forming the tubular devices are disclosed. The secondary layer can be formed on the pipe component by welding or casting. The tubular devices can be used in conductors, casing, drill pipe, production tubing, pipeline and risers.

A method of insulating an object, such as a pipe for carrying crude oil or natural gas, includes providing an insulating fluid comprising a base fluid and a viscosifying agent, wherein the viscosifying agent comprises silicon dioxide. The base fluid is optionally a non-aqueous base fluid. The method further includes the steps of adding the insulating fluid to a container, and placing the object in the container. The object which is insulated can be located remotely or subsea.

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.