The steel lazy wave riser (SLWR) was first installed in 2008 at Brazil’s BC-10 field. Since then, it quickly became a popular and competitive riser solution for application in deepwater locations. This is due to the riser’s satisfying performance when exposed to dynamic loadings and the relatively simple configuration (particularly when compared to hybrid risers).
However, as it was put to use only quite recently, this riser concept is still lacking in technology qualification and design validation, in addition to very little field experience and data. Felisita’s thesis presents a study on the application of SLWR in harsh environments combined with high-motions vessels.
Strength and fatigue
The main objective is to demonstrate and document various design aspects for application of SLWR in such situation. Main analysis aspects include strength and fatigue of the riser, specific challenges from the environments (internal solitary waves) and installation operation for the riser.
In addition, a potentially novel concept using SLWR for application in areas prone to glacial ice is also included.
These findings can be applied to the design of SLWR, particularly for understanding the riser’s dynamic performance in correlation with its geometric shape, the influence from soil characteristics and VIV.
The potentially novel sidestep concept, using SLWR for application in areas with glacial ice, is very useful as it provides an additional safety barrier prior to turret disconnection.
The design method against internal solitary wave can be used as a verification method during early stages of riser design/field development planning.
The results from installation analysis can be used to identify possible installation methods, vessels and required weather window for installing SLWR in harsh environments.
Thesis and defence
Airindy Felisita’s thesis is titled «On The Application of Steel Lazy Wave Riser for Deepwater Locations with Harsh Environment». The research was supported by DEA E&P Norge AS.