This paper gives an introduction to the results from a 4 year Joint Industry Project (JIP) named "Design procedures and acceptance criteria for deep water risers". The objective of the JIP is to provide the Oil & Gas industry with practical guidelines for the design and analysis of metallic risers with focus on deepwater application. The design and analysis guideline includes the following: safety classes linked to consequence of failure, limit state design method, load effect and resistance design format (LRFD) and recommended analysis procedures.
The riser system constitutes a key element in relation to availability and safety in all phases spanning from drilling to production/export/import. Exploration and production of hydrocarbons in deepwater represents a new challenge to design and analysis of riser systems compared to shallow water applications. Standard industry practice for riser design, e.g. API RP 2RD (1998), apply the traditional working stress design (WSD) format where structural safety is taken care of by using a single usage (safety) factor. One of the limitations of WSD is that a single safety factor leads to a safety level that is strongly dependent on the load conditions. Design codes gives also normally limited guidance on how to establish extreme and fatigue load effects to be used in the code checks. In response to the above situation, DNV, SINTEF and SeaFlex initiated a Joint Industry Project (JIP) called "Design Procedures and Acceptance Criteria for Deepwater Risers" in December 1995. The main objective of the JIP is to assist exploration and development of deepwater fields, by providing safe and efficient design and analysis procedures for metallic risers. The JIP has 3 phases, where phase 3 is ending 1999. The product of Phase 3 will be a guideline for design and analysis of metallic risers.
