Optimization procedures for alternative configurations of risers

Edmundo Queiroz de Andrade (Petrobras)

The interest in the application of a riser connected to a vessel for exploration and production in deep water, has motivated the need to carefully study this concept due to the high offsets and vertical motions imposed by the vessel at the top of the riser. Petrobras has developed through its Research Center the study of different steel riser configurations. The steel lazy-wave riser (SLWR) has been considered as an adequate solution due to its structural dynamic behavior and costs when compared to other configurations. In order to reduce the engineering time in generating and analyzing several configurations, the modeFRONTIER software was used in association with Petrobras in-house software to help define a model that could achieve all design verification phases more easily. This paper presents the experience with the use of an optimization procedure applied to facilitate the design of a SLWR connected to a FPSO unit offshore Brazil.