Procedure for Analyzing Rigid Risers Launched in Lazy Wave: Numerical and Analytical Approach

Exploration of oil in deep and ultra-deep waters requires overcoming various technical challenges, particularly those associated with the design of risers. In the search for solutions to enable the use of rigid steel risers at great depths, the use of floaters that adjust the curvature of the riser has been extensively studied. The configuration known as Lazy Wave emerges as an innovative and effective solution. This configuration reduces the tension and wear on the riser by decoupling the movement of the floating unit from the riser’s contact point with the seabed, which minimizes the load on the structure, resulting in a more efficient operation and extending the system's lifespan. This paper presents a procedure to determine and evaluate the static configuration of the structure in the Lazy Wave regime, based on practical input data such as the total riser length, depth, the well’s position relative to the floating unit, and the arrangement of the floaters. An analytical approach is performed using catenary equations, and a numerical approach is conducted using a finite element model built in ANSYS Mechanical. The results obtained from both approaches show a consistent correlation with each other and provide a solid theoretical foundation for future dynamic analyses of risers in the Lazy Wave configuration.