bp has selected Allseas to complete the subsea pipelay scope for its ultra-deepwater Greater Tortue Ahmeyim (GTA) natural gas project offshore Mauritania and Senegal.
Allseas will undertake GTA offshore pipelay works in early December 2023 using the world’s largest construction vessel Pioneering Spirit. Installation support will be provided by Allseas’ offshore construction support vessel Oceanic.
The contract covers the installation of approximately 75 kilometres outstanding on the two 16-inch export pipelines with field termination assemblies (FTAs) in water depths between 1,500 and 2,800 metres, and four 10-inch CRA infield lines with FTAs up to two kilometres long in 2,800 metres of water.
Highly complex and pipelay projects with fast-track planning and execution
bp and Allseas commercial and engineering teams worked tirelessly to evaluate the technical feasibility of installing the pipelines and subsea structures, which were originally designed for installation with a J-lay solution.
“This agreement demonstrates both our willingness and ability to take on highly complex and pipelay projects with fast-track planning and execution scopes,” says Pieter Heerema, Chief Executive Allseas.
“We are excited to work with bp on this project, this opportunity re-establishes the partnership between our two companies and creates a platform on which to grow and strengthen future collaboration between bp and Allseas.”
The installation of mixed-diameter pipelines and subsea structures in ultra-deepwater is the perfect fit for Allseas’ S-lay vessel Pioneering Spirit, which boasts a record-breaking 2,000-tonne tension holding capacity. To install the 10 FTAs, the vessel will be fitted with a special 1,000-tonne J-mode installation frame, designed in-house and built at Allseas’ Heijningen fabrication yard in the Netherlands.
As pioneers of dynamically positioned S-lay technology, characterised by its fast installation speeds in all water depths, Allseas has installed more than 27,500 kilometres of pipeline worldwide.
