Session: 04-04-06 Pipe-Soil Interaction

Paper Number: 127562

127562 - Employing an Asymmetrical Anchoring Solution for Rigid Flowline Riser System Adopting Single Torpedo Piles 

This paper introduces the technical pipeline anchoring solution deployed for rigid flowlines of the Buzios field, installed in the ultra-deep waters of the Santos Basin.

Based on the usual combination of an anchoring pile, a chain and an In-Line Anchor (ILA) mounted as part of a rigid flowline, the unprecedented concept used for this project bears two specificities: the use of torpedo piles, and an asymmetrical configuration with a single fixed point.

As being the first project of this kind to deploy this concept, this paper addresses the technical challenges associated to it, as well as the specificities it brings to the flowline design methodology in order to guarantee the robustness of the system.

Chain slack management stood as the most critical one, due to the inherent extra chain length needed to connect the torpedo pile to the ILA, followed by the relative angle between the chain and the flowline.

Although one might surmise the design to be governed by the extreme values of these parameters, the analyses carried out demonstrated specific limit states to be occasionally maximized at intermediate values, thus requiring more scrutiny and precision in the load cases matrices, effectively increasing the quantity of finite element simulations.

Moreover, this design vastly relied on predefined installation tolerances for both the pipeline and torpedo pile. Thus, in order to provide additional operational flexibility and further stretch these tolerances, separate assessments aiming at the definition of a limit chain angle were performed.

Finally, this paper discusses the importance of properly implementing and modelling the ILA in global flowline models. Due to the asymmetry inherent to this solution, it has a pivotal impact on the ILA and surrounding pipeline, going as far as to alter the definition of the governing configuration.

While noticeable, this increase in engineering work proved a worthwhile investment, as the use of a single torpedo pile has brought substantial operational advantages. In addition to the evident benefits along the whole chain of supply of these items, the gained advantages include project readiness with regards to pre-fabrication, flexibility in vessel selection, along with significant reductions in installation time.

Presenting Author: Simon Grevet SAIPEM

Presenting Author Biography: Lead Flowline System engineer for Saipem in Paris. Manager of the digital transformation of Saipem's subsea field development analysis tools to improve project engineering quality. Also involved in the digitalisation and development of the flowline system design tools, including thermo-mechanical analyses and finite element modelling.

11-year experience in mechanical flowline design with contribution on various EPCI projects.

Holder of a Master of Science degree in Civil Engineering from the Ecole Nationale des Ponts et Chaussées (Ecole des Ponts ParisTech).

Authors:

Simon Grevet SAIPEM
Bruno Bianco SAIPEM
Steve Maior SAIPEM
Eduardo Volpi SAIPEM
Rachel Genzani PETROBRAS
Rafael Solano PETROBRAS
Diego Pavone SAIPEM