Structural and Hydrodynamic Aspects of Steel Lazy Wave Riser in Deepwater

Abstract

Exploration of oil and gas in deep and ultra-deepwater under harsh weather condition is challenging. A steel lazy wave riser (SLWR) is considered to be a cost-effective alternative to get the gas or oil flow up to the platform under these conditions. The staggered buoyant section provides buoyancy force which forms an arch shape of the SLWR. This arch shape makes the SLWR configuration flexible and isolates the dynamic responses of the upper part and lower part of the riser. However, there is a lack of full understanding of the behavior of SLWRs. This is, due to a complicated loading from waves, vessel motions and flow induced vibrations caused by ocean currents, complex structural configurations, and non-linearities. Time-domain simulation is necessary to accurately predict the dynamic responses and capture the non-linearities. Realistic fatigue damage calculation is essential in the design phase of SLWR. The design of SLWR could be optimized with a better understanding of the dynamic responses of SLWR.