Service line for offshore platform - has tube mounted on platform above mud-line with line installed after settlement

摘要

The guide tube (40) for a service line (90) to an offshore structure (20) has a longitudinal upper segment (44) a longitudinal lower end (54). To instal the line, the upper segment is connected so that it cannot move laterally w.r.t. the structure, but can be moved longitudinally. The lower end is also restrained laterally. The tube is moved w.r.t. the structure to an elevation at which the lateral segment is above the highest expected mud line (28) the structure after setting. The structure is placed on the seafloor and settles to its final elevation. The tube is lowered with the lower end is a sheet distance above the sealfloor. The line is drawn through the tube and the lower end released to descend to the seafloor.