| 摘要 |
There is disclosed method and apparatus for paying out pipelines (200, 205) from a vessel, in particular relating to the offshore oil and gas industry. Relative movement between the vessel (14) and the seabed can be an obstacle, as it can induce unacceptable pipeline stress. Active tension regulation systems (230) exist, but they are unsuitable for applications involving multiple pipelines. Passive systems (260), however, are suitable. A method is disclosed whereby, prior to attachment to a main pipeline (205) subject to motion, a piggyback pipeline (200) is bent temporarily by plastic deformation to form a curved portion (340) after it leaves a supply reel (250), the curved portion by elastic deformation isolating the pipe as it leaves the supply from longitudinal oscillatory stress and motion. Suitable apparatus comprises pipeline feeder (420), bender (440) and straightener (460), arranged so that the curved portion is free to expand and contract elastically, thereby isolating the pipeline upstream of the apparatus from longitudinal oscillatory stress and motion. |
