DeepStar Global Offshore Technology Development Program: New Generation Computational Capabilities in Nonlinear Dynamic Simulations of Flexible Riser Systems

摘要

A method for accurate prediction of flexible riser behavior and component stress computations under irregular wave inputs is a subject of major interest to offshore oil and gas operators. The initial full field procurement for flexible risers can be upwards of 500M USD, with replacement costs of a single flexible riser often approaching 40M USD. The reliability of fatigue life estimates is therefore critical to the successful long term operation of flexible risers. Computational constraints, however, continue to prevent realistic simulations and meaningful fatigue life predictions. To address this challenge, a next generation computational capability for nonlinear dynamic simulations of flexible risers has been developed. The FLEXAS solver overcomes computational constraints which limit conventional flexible riser analysis methods by implementing Nonlinear Dynamic Substructuring (NDS). This advanced multibody framework enables the incorporation of detailed finite element models into global nonlinear dynamic simulations under realistic environmental and system loads. Prior to this development, simulating these complex models for spans greater than a few pitch lengths was computationally not feasible even in static cases. The purpose of this DeepStar project is to validate the FLEXAS solver for nonlinear dynamic simulations of flexible risers against numerical and experimental references, and includes extensive local and global benchmarking.