LAYING OFFSHORE PIPELINES

摘要

An apparatus for laying pipe from a vessel is disclosed. The apparatus includes a traveling working table that can be lowered to allow clearance for horizontal movement of a tensioner over an in-line structure. Another embodiment employs a main working table, a tensioner positioned above the main working table, and an auxiliary working table positioned below the main working table. The auxiliary working table can be lowered to accommodate an in-line structure, which lies in a gap extending from the tensioner through the level of the main working table to the level of the auxiliary working table. The apparatus enables the tensioner to be mounted lower on the vessel to benefit stability and cost and to facilitate retrofit of the apparatus to existing vessels.

主权项

1. A pipelaying vessel in combination with a pipe incorporating an in-line structure, the vessel comprising:
a clamp supporting a catenary of the pipe extending from the vessel to the seabed, the clamp being located at a level below, or being movable to a level below, a working deck of the vessel, the in-line structure being positioned above the clamp, connected to an upper end of the catenary supported by the clamp; and a tensioner that is positioned with a vertical clearance above the working deck and is movable transversely with respect to a launch axis of the pipe from a retracted position to a deployed position above the in-line structurewherein the in-line structure has a height along the launch axis that exceeds the vertical clearance between the working deck and the tensioner and the level of the clamp is below the working deck by a distance sufficient to accommodate the in-line structure under the tensioner when the tensioner is in the deployed position.