Abstract: Lined pipelines with different inner diameters are spooled successively onto a reel while their constituent pipe stalks are cyclically pressurised internally to combat wrinkling of the liner. A first, variable diameter pig is advanced to a trailing end of a first pipeline. A transition joint is attached to the trailing end of the first pipeline to effect a transition from the inner diameter of the first pipeline to the different inner diameter of a second pipeline. A leading end of the second pipeline, containing a second pig, is attached to the transition joint. The first pig is driven through the transition joint into the second pipeline. The diameter of the first pig changes to match the inner diameter of the second pipeline. The first and second pigs are then driven along the second pipeline when assembling the second pipeline from a succession of pipe stalks.

Abstract: A method of installing a subsea riser comprises placing an elongate negatively-buoyant support on the seabed and, when laying the riser on the seabed, guiding a riser portion onto the support to extend along and be cradled by the support. A hogbend region of 5 the riser is then formed by conferring positive buoyancy on the support to lift the support and the riser portion away from the seabed. An element of the support comprises a riser support disposed in a longitudinally-extending open-ended gap between buoyancy volumes disposed on opposite sides of 0 the gap. Coupling formations such as hinge portions can couple the element to a like element. When so coupled, the gaps of those elements align to define an upwardly-opening, longitudinally-extending groove to receive the riser.

Abstract: In a method of joining a structure to a water-filled pipeline aboard a reel-lay vessel, a trailing end portion of the pipeline is suspended upright on a reel-lay tower. Water is drained from the trailing end portion while being retained in an inclined portion of the pipeline extending from the tower to a reel of the vessel and in a spooled portion of the pipeline coiled on the reel. The structure is joined to a trailing end of the pipeline after inserting a pig into the trailing end portion through the trailing end. Pumping additional water into a leading end of the pipeline on the reel propels the pig from the trailing end portion into a conduit of the structure while flooding the trailing end portion. This expels air through a port of the structure that was trapped in the trailing end portion between the pig and the structure.

Abstract: Lined pipelines with different inner diameters are spooled successively onto a reel while their constituent pipe stalks are cyclically pressurised internally to combat wrinkling of the liner. A first, variable diameter pig is advanced to a trailing end of a first pipeline. A transition joint is attached to the trailing end of the first pipeline to effect a transition from the inner diameter of the first pipeline to the different inner diameter of a second pipeline. A leading end of the second pipeline, containing a second pig, is attached to the transition joint. The first pig is driven through the transition joint into the second pipeline. The diameter of the first pig changes to match the inner diameter of the second pipeline. The first and second pigs are then driven along the second pipeline when assembling the second pipeline from a succession of pipe stalks.

Abstract: A method of installing a subsea riser includes placing an elongate negatively-buoyant support on the seabed and, when laying the riser on the seabed, guiding a riser portion onto the support to extend along and be cradled by the support. A hogbend region of the riser is then formed by conferring positive buoyancy on the support to lift the support and the riser portion away from the seabed. An element of the support includes a riser support disposed in a longitudinally extending open-ended gap between buoyancy volumes disposed on opposite sides of the gap. Coupling formations such as hinge portions can couple the element to a like element. When so coupled, the gaps of those elements align to define an upwardly opening, longitudinally extending groove to receive the riser.

Abstract: In a method of joining a structure to a water-filled pipeline aboard a reel-lay vessel, a trailing end portion of the pipeline is suspended upright on a reel-lay tower. Water is drained from the trailing end portion while being retained in an inclined portion of the pipeline extending from the tower to a reel of the vessel and in a spooled portion of the pipeline coiled on the reel. The structure is joined to a trailing end of the pipeline after inserting a pig into the trailing end portion through the trailing end. Pumping additional water into a leading end of the pipeline on the reel propels the pig from the trailing end portion into a conduit of the structure while flooding the trailing end portion. This expels air through a port of the structure that was trapped in the trailing end portion between the pig and the structure.