OPERATORS EXPERIENCE WITH FLEXIBLE RISERS

摘要

Norsk Hydro has more than 150 flexible dynamic risers and service lines in operation. Norsk Hydro's experience with flexible risers started in 1987 when Petrojarl 1 commenced test production at the Oseberg Field. The paper tells the story about Norsk Hydro's experience through the 15 years of trials with a new and complicated product. This paper will focus on "what went wrong". This may seem unfair to the product! However, without flexibles we would probably not have seen such successful field developments as the Troll B and C, Njord, Visund and Snorre B. Challenging production and installation schemes have been put forward and fulfilled. However, hopefully this paper can give an insight in failure modes, and so forth give input to enhanced solutions in order to avoid similar situations in the future. This paper gives an overview over the different approaches which have been taken to give a better qualification of the lifetime prediction of the risers. Some of the specific projects will be presented in detail in other papers on this conference.