Double Pipe Ensures Reliable Insulation of Offshore Pipelines

At the beginning of the eighties, the offshore technology relevant to thermally insulated pipelines did not offer a cost-effective and technically challenging solution. Nowadays, the oil industry requires an ever-increasing use of thermally insulated pipelines with improved reliability in the offshore and, more particularly, for the exploitation of arctic fields. The present solution has been developed on the basis of easy handling, conventional laying procedures and long-term integrity criteria adopting a special field joint connector. This type of connector allows the two coaxial pipes to be assembled in a workshop and the individual double pipe sections to be connected in the field by means of a standard butt weld. This paper includes: the presentation of the DPIS (Double Pipe Insulated System) concept, which deals with the structural and thermal insulation aspects relevant to this new system; and a brief description of the first application of the DPIS for a pipeline connecting an unloading terminal for heavy oils to onshore plants.