Procedure for analysis of lazy wave steel caterany riser: numerical and analytical approach

Deep water and ultra-deep water oil exploration require overcoming several technical challenges, particularly those associated with riser design. In the search for solutions to enable the use of rigid steel risers at great depth, the use of buoyancy devices that adjust the curvature of the riser has been extensively studied. This configuration reduces the tension and wear of the riser by decoupling the movement of the floating unit from the contact point of the riser with the seabed, thus minimizing the structural load, leading to improved operational efficiency and extended system lifespan. This paper proposes a procedure to determine and evaluate the static configuration of the riser structure in the lazy wave regime, using practical input parameters such as the total length, depth, position of the well relative to the floating unit, and arrangement of buoyancy devices. An analytical approach based on the catenary equations is conducted, and a numerical approach is carried out using a finite element model developed in ANSYS Mechanical. The results obtained from both approaches show a consistent correlation and provide a solid theoretical foundation for future dynamic analyses of risers in the lazy wave configuration.