Session: 04-03-04 Thermo-Mechanical

Paper Number: 102990

102990 - Anchoring System of Rigid Riser – Flowline Connection With Torpedo Piles 

This paper discusses the innovative methodology for anchoring system the rigid riser – flowline transition (TRF) in the Mero Field located in ultra-deep waters of the Santos Basin, offshore Brazil. The Mero Field is located in the Northwest area of the Libra block.

Mero 1 project is composed by rigid MLP flowline systems which operate under high temperature and high inner pressure (HPHT) conditions, two different fluid types (oil and water alternating gas, i.e. WAG), permanent and transient flow regime with several predicted shutdown/start-up cycles during design life, unburied condition, with fully restrained anchoring system in the flowline at the well side and compliant in-line anchoring system (i.e. torpedo piles) at TRF side interconnecting the SLWR.

Suction piles connected to an in-line structure via mooring chain or in-line structure with pin piles are commonly used to anchor the rigid riser – flowline connection to the seabed. Both provide a robust anchoring solution with limited uncertainty with respect to the capability of the system to move under operating condition. The drawback of those solutions is that they often require procurement of heavy subsea structures and availability of large construction vessel for their installation.

Despite the significant track record in the oil and gas industry for the use of torpedo piles for anchoring flexible and umbilicals risers to avoid large displacement of the lines once installed or to enable design of subsea layout with tight curves or for anchoring of Floating Production Storage and Offloading units (FPSO), their use for anchoring of rigid riser-flowline connection was a first on Mero-1 project.

The paper addresses the benefits and challenges associated with the use of torpedo piles for anchoring of rigid riser-flowline connections looking at every step of the process and in particular the following ones : definition of riser – flowline loading to be transferred to the anchoring system, behavior of anchoring system in operating condition (rendering of slack from embedded mooring chain, soil consolidation, requirement for pre-tensioning, etc.), flowline design limitation and requirement to avoid overloading of subsea equipment associated with the rigid line (pipeline end termination, suction pile, sleepers, etc.) and installation challenges to deliver an effective pipeline system.

Presenting Author: Matthieu Novel TechnipFMC

Presenting Author Biography: 19 years of experience in Energy industry, gathered mostly in Oil and Gas deep water projects in Africa, USA and Brazil, leading design, procurement, fabrication, commissioning and installation of a wide range of subsea equipment including among others flexible, umbilical and rigid pipes.

Authors:

Matthieu Novel TechnipFMC
Rachel C. Genzani Petrobras
Rafael F. Solano PETROBRAS
Adel Jebali TechnipFMC
Marcio Scultori TechnipFMC
Florent Camilleri TechnipFMC
Carlos Valer TechnipFMC
Olivier Mustiere TechnipFMC