Abstract
NORSOK U-001 provides general requirements for the development, design and manufacture of subsea production systems intended for use on the Norwegian Continental Shelf. NORSOK U-001 5th edition was released in December 2021. Annex B defines requirements for the structural design, materials and fabrication of subsea wellhead, subsea trees, and completion/workover riser systems. An overview and background for the estimation of the static structural capacity as given in this Annex are presented in this paper.
Static structural design analysis methods for combined loading design and pressure design of riser load path components are presented. The link between material requirements and the assumptions made by the finite element based static design analysis methods are emphasized (e.g., ductile failure). Examples of their use for the design of common subsea components such as pipes, wellhead connectors and bolted flanges are given.
The static structural design analysis methods in Annex B have evolved from previous revisions of this standard to address gaps and the missing link between the analysis methods and material properties. The paper ends with a discussion on the limitations of the current edition and outlines future work that could be undertaken to improve and simplify future revisions of Annex B in NORSOK U-001.
