Pipe lay Barge system will be used to build the offshore portion of the pipeline, which consists of a mobile platform or barge where the pipeline is welded before being laid on the seabed in a continuous fashion. Two pipe lay methods are commonly used for this type of installation: the Slay method and J-lay method.
The S-lay method is suitable for use both in shallow and deepwater areas (up to 2500 meters water depth depending on pipe diameter) and involves welding the pipe sections horizontally, and continuously ‘feeding’ the jointed sections over the barge’s pipelay stinger in such a way that the pipeline forms an “S” shape from the barge’s exit point up to the touchdown point on the seafloor.
In the J-lay method, the pipes are assembled and welded in a vertical mode in a tower erected on the centre or side of the barge and as the platform moves forward, the jointed pipeline is lowered near vertically in a J-shape from the launching point down to the bottom of the sea.
J-lay method is considered to be suitable for 400 m. to 3500 m. water depth depending on pipeline diameter. As the search for hydrocarbons moves into ever deeper waters, technologists are developing new construction methods to meet the industry needs. We will be able to use either of the pipe lay methods for building the proposed gas pipeline in such ultra-deep waters