Dynamic Analysis of a Flexible Riser in Shallow Water

摘要

This thesis work is focused on the dynamic behavior of a flexible riser in shallow water byproviding a suitable riser configuration for deployment in conjunction with a Floating Production Storage andOffloading Unit (FPSO) in a harsh environment. This work is justified by the rising demand of exploration andproduction in shallow water, and harsh environments. A lazy wave riser (LWR) configuration that is attractivefor shallow water deployments has been used. This configuration allows the FPSO motion to be decoupled fromthe touchdown point (TDP) of the riser when using a buoyant system. The design basis was established usingtypical environmental and design data for the Gulf of Guinea, taking into account the FPSO motions andhydrodynamics coefficients and checking against relevant design codes. To accurately predict the dynamicbehavior of a flexible riser in shallow water, an analysis model has been created in orcaflex. The main objectivewhen creating an analysis model is to reproduce the reality. FPSO motions and other hydrodynamic coefficientwere imported to orcaflex and an evaluation of the static and dynamic analysis has been done. Bending radiusfor all load cases considered are within (Maximum Bending Radius) MBR limit. The tension reported at the endA and (Pipeline End Terminal) PLET location are in a reasonable limit. The extreme response behavior issatisfactory. Overall, this thesis work showed that the LWR is a suitable riser configuration for deployment inconjunction with turret moored FPSO in shallow water, harsh environmental conditions.