Developments of subsea pipeline technology for Norwegian waters

Norwegian waters have been a main arena for development of subsea pipeline technology over the last 25 yr. The gas transportation systems from Norway to continental Europe comprise the largest and longest subsea pipelines in the world. The challenges of pipeline projects irt and from Norwegian water s include large water depths, large diameters, long distances, uneven seabe d rocky landfalls, and hostile environmental conditions, all within strict requirements for safety, regularity, cost efficiency, and environmental imp act. This paper provides an overview of the technology developments perform ed in this period, initially focusing on ability to cross the deep waters o f the Norwegian trench by large-diameter pipelines, then on subsea design a spects such as stability, free span design, and mapping technology, and in recent years also on improvements in transportation efficiency, cost reduct ions, and operational issues. The paper is based on a Plenary Lecture prese nted at the 1998 OMAE Conference in Lisbon, Portugal. [S0892-7219(00)00601- 4].