Advances in Offshore Pipelaying - State of the Art

ABSTRACT Advances in offshore pipelaying during the seventies have produced newproven techniques and new generation layvessels culminating in the flawlessimplementation of unprecedented projects such as the Transmed (2,000 ft of w.d.rugged seabed). The ensuing state of the art is based upon integrated automation, refinedproven mathematical programmes, consequent operational reliability andaccuracy. Further progresses will initiate from an integrated constructional approachencompassing theoretical specific preparation, planned implementation, and oreestablished procedures for after-lay interventions for sealine stabilisationand maintenance. New techniques and equipment will be required in frontier areas andultradeep water. Recent pipelaying operations consistent with such qualityapproach are described, mentioning as well projects for deep water repair afterlay. During the Seventies a tremendous advance in offshore pipelaying has takenplace as the projects of this segment of the industry have progressed inincreasingly deep & severe environment, with special reference to the NorthSea. Novel techniques and new generation lay-vessels have been conceived, implemented and validated on actual operations. The most impressive – if not the most apparent – advances have beenregistered in the detailed knowledge and consequent increasing degree ofcontrol of operations offshore: a routine inquiry of today and the relevant bidincorporate a wealth of technical and technological considerations andimplications unthinkable 10 years ago for even the most advanced pipelayingprojects of that time: simulation runs, bi-tridimensional pipe programmesextending also into the dynamic domain, theoretical analysis based oncalibrated mathematical models are no longer confined with scientific exercisesof learned scholars but they have an operational specific role within theindustry and the contractors alike.