| 摘要 |
The invention describes a system with a system for use in petroleum production at sea, with a guide frame (2) for one or more riser pipes (3), on a semisubmersible production vessel (1), with one or more main buoyancy member (4) arranged separately on at least one riser (3) to carry the main part of the riser's (3) weight. Each riser (3) is arranged to separately carry a Christmas tree (6) on top, near the main deck (10) of the vessel (1). The guide frame (2) comprises vertical main elements (7) arranged to extend vertically downwards from the deck (10), through the splash zone and through the upper, more wave- and current- influenced zone of the sea. The guide frame (2) has horizontal guide plates (20) comprising vertically open cells formed of a horizontally arranged framework (21) of beams (21'), with lateral stabilization devices (24) for guiding the riser's (3) and the main buoyancy member's (4) vertical relative movement and restricting the horizontal relative movement with respect to the guide frame (2). The guide plates (20) are arranged in at least two levels on the guide frame (2); a lower guide plate (20) arranged in level with the lower ends of the vertical main elements' (7), and a guide plate (20) arranged in a level just below or near the splash zone. At least one main buoyancy member (4) is arranged for being held on the riser (3) in level with, and guided by the lateral stabilization devices (24) arranged in one or more guide plates (20), below the upper, more wave- and current-influenced zone near the sea surface, and with the risers (3) being essentially without buoyancy elements through the splash zone, for being less exposed to the water forces in the upper zone of the sea.
|
