A method of installing a subsea tie in conduit comprises unspooling or manufacturing a steel rigid lined pipeline aboard an installation vessel and launching the pipeline progressively into water. A distal end of the tie-in conduit is coupled to a proximal end of the pipeline above the surface and is then launched into the water coupled to the pipeline. The suspended weight load of the pipeline is supported by an A&R wire connected to the proximal end of the pipeline, defining a load path that bypasses the tie-in conduit. A proximal end of the tie-in conduit may be suspended from that wire. The tie-in conduit is of composite or flexible pipe, hence being pliant relative to the lined rigid pipeline and maintaining its internal corrosion resistance. After landing on the seabed, the tie-in conduit may be deflected relative to the pipeline for connection to a subsea connection point.

A pipe-in-pipe assembly with thermally-insulating spacers positioned in an annulus to act radially between inner and outer pipes is disclosed. The spacers have at least one circumferentially-extending array of circumferentially-spaced ribs that define longitudinally-extending passageways in gaps between neighbouring ribs of the array. Cables including heating elements extend longitudinally along the annulus outside the inner pipe. The cables extend longitudinally along the passageways. At least one insulation layer disposed radially outboard of the cables has insulating elements disposed in the gaps between the ribs and/or an insulating layer extending around the inner pipe, positioned radially outboard of the ribs and bridging the gaps. Bands encircle and retain components of the insulation layer. Insulation may also be disposed on the inner pipe between first and second arrays of ribs, those arrays being spaced longitudinally from each other.

Techniques and systems to reduce deflection of a riser extending from an offshore platform. The riser may include a flow guide. The flow guide may receive a fluid. The flow guide may also include one or more outlets that are configured to transmit the fluid. This transmission of the fluid by the one or more outlets may counteract currents or other factors to mitigate deflection in the riser.

A method of sealing an annulus between inner and outer pipe sections of a pipe-in-pipe system includes positioning a sealing mass in the annulus in contact with the inner and outer pipe sections. Deforming the sealing mass occurs, for example by shearing and compression, by effecting relative longitudinal movement between the inner and outer pipe sections. Fixing the inner and outer pipe sections against reverse relative longitudinal movement to maintain deformation of the sealing mass is then performed. The inner pipe section and a displaced outer pipe section may be fixed by welding them to respective pipes of an adjoining pipe-in-pipe structure. Opposed ramp surfaces, each being similarly inclined relative to the longitudinal direction, extend into the annulus from respective ones of the pipe sections such that the sealing mass may be compressed between the ramp surfaces.

A method for producing a tubular underwater pipe including: assembling a structure of peripheral metal elements (3A, 3B, 3C) wound in an S-Z configuration about a central flexible core (1) as the core is driven in movement along its longitudinal axis; providing an inductive sensor (12) arranged for rotation about the central flexible core (1) in a manner synchronized with the longitudinal movement of the core so that the sensor scans the periphery of the structure opposite and in the immediate proximity of peripheral elements wound about the core and during the assembly step; using the sensor (12) to acquire measurement signals (S) of which the amplitude varies according to whether or not the sensor (12) is located opposite a peripheral element during the rotation of the sensor (12); and using the measurement signals to control the positioning of the assembled peripheral elements.

A pipe assembly station for performing operations on a field joint during pipe assembly has an active rail extending around an opening through which the pipe can pass. Tool carriages are arranged to traverse along the active rail and around a periphery of the pipe. The station also comprises a standby position, distanced from the active rail and a switch arranged to transfer the tool carriage from the active rail to the standby position. By providing such a combination of a rail and a standby position, a tool carriage can be brought into position on the active rail to perform a pipe joining operation and can be subsequently set back to the standby position, where it is out of the way of operations taking place on the pipe. Such a switching arrangement allows for more effective use of the limited space around the joint.

A pipe assembly station for performing operations on a field joint during pipe assembly has an active rail extending around an opening through which the pipe can pass. Tool carriages are arranged to traverse along the active rail and around a periphery of the pipe. The station also comprises a standby position, distanced from the active rail and a switch arranged to transfer the tool carriage from the active rail to the standby position. By providing such a combination of a rail and a standby position, a tool carriage can be brought into position on the active rail to perform a pipe joining operation and can be subsequently set back to the standby position, where it is out of the way of operations taking place on the pipe. Such a switching arrangement allows for more effective use of the limited space around the joint.

A method of controlling subsea laying of an elongate article includes guiding the article using a submersible vehicle such as an ROV that carries a guide tool. The guide tool has a sleeve through which the article moves axially during laying, while the vehicle applies cross-axial guide forces to the article via the sleeve. Also disclosed is a guide tool including a sleeve through which the article can move axially during laying, and a grab handle whereby a submersible vehicle may hold the tool using a grabber. Alternatively, the guide tool can be attached to or integrated with the vehicle.

A method of controlling subsea laying of an elongate article includes guiding the article using a submersible vehicle such as an ROV that carries a guide tool. The guide tool has a sleeve through which the article moves axially during laying, while the vehicle applies cross-axial guide forces to the article via the sleeve. Also disclosed is a guide tool including a sleeve through which the article can move axially during laying, and a grab handle whereby a submersible vehicle may hold the tool using a grabber. Alternatively, the guide tool can be attached to or integrated with the vehicle.

A method of assembling a pipe on a water-supported floating platform is provided. The platform includes an open central bay, and a gantry on the platform is arranged so as to surround at least a portion of the bay. The method includes providing a pipe intake assembly and staves on the platform; transferring the pipe intake assembly to the interior space of the bay; assembling the individual staves on the pipe intake assembly in an offset construction; lowering the pipe portion within the bay and into the water until the upper ends of the staves reside within a lower portion of the gantry; increasing the length of the pipe portion by assembling additional staves to the upper ends of the assembled staves; and repeating the step of increasing the length of the portion of the pipe until the pipe has a desired length.