Petrobras expects key change for flexible pipes

Brazil's Petrobras expects that the use of composites to replace some steel structures in flexible pipes in deep-water fields will be a key enabler in the future, especially when it comes to key developments in the prolific pre-salt province.

Walter Carrara Loureiro, a subsea engineer at Petrobras, said composites would fit perfectly at projects with highly pressurised reservoirs featuring corrosive chemical components such as carbon dioxide and hydrogen sulphide, adding the Mero field is a suitable candidate for future application.

“By using composites in our future projects, we will be able to get to deeper water depths, have larger pipes and maybe change the entire layout of our subsea systems,” Loureiro told a panel on applied technologies in the Libra-Mero field at the OTC Brasil 2019 conference.

Petrobras has for a long time been considering the potential application of hybrid composites in free-hanging catenary risers and flowlines at Mero.

The main benefit of using free-hanging solutions is the time reduction for the installation of the riser system, because installing buoys under the lazy-wave configuration can be time-consuming and costly.

According to Loureiro, the use of composite materials in pipes would reduce installation costs by more than 30%, as Petrobras would need smaller and simpler pipelaying support vessels to carry out the work.

“Composites will reduce worries about corrosion but will bring other issues to the table such as fatigue and long-term degradation. That is why we are conducting a very comprehensive qualification process with suppliers,” he added.

Petrobras has been using Mero as a sort of test ground for pioneering technological applications and has already started replicating some successful initiatives at other deep-water fields. The state-controlled company is using eight-inch diametre lines to produce from the Mero extended well test with the Pioneiro de Libra floating production, storage and offloading vessel, and is assessing its use at other offshore developments.

“With regards to well drilling, there were innovations developed and applied in the bottom hole assembly columns of the early phases of the Libra wells, which resulted in the construction of less complex wells in less time,” Petrobras told Upstream.

“These optimisations have already been successfully implemented at other deep-water fields operated by the company.”