Deepwater Pipeline Installation by Reel-lay Method

Abstract

Abstract The reel-lay method is generally the most effective way of installing infield subsea flowlines and risers particularly for sizes up to around 16 inch. This paper describes one of the most advanced reeled pipeline installation vessels in the world, the Seven Oceans, and the variety of pipelines and risers that she has installed including the welding and inspection of high fatigue life SCRs and sour-service flowlines. The paper goes on to present various recent developments for reeled installation including HFI pipe, PE lined pipe, mechanically lined pipe, clad flowlines and SCRs, high strength pipe, hybrid risers and electrically heated-traced flowlines. These show the continuing attraction of reel-lay for ever more technically demanding work and that for options such as electrically heat-traced flowlines that reeling will be the main vessel based installation method. 1. Introduction 1.1 Vessels The reeled pipelay concept has been in use since the Pipelines Under the Ocean (PLUTO) project across the English Channel (Purvis, 1946). The reel ship Apache (Anon, 1979) is a notable name in the development of the technology and was first operated in 1979. Other reel lay vessels followed including the Skandi Navica (Clarkson, 2006) now named as Seven Navica. Another notable vessel was the Deep Blue (De Soras & Cruickshank, 2000) and more recently the Seven Oceans. Other reeled vessels also exist but the characteristics of these main ones are given in Table 1.