bp PLC has let a contract to Allseas to complete subsea pipelay for the ultra-deepwater Greater Tortue Ahmeyim (GTA) natural gas project on the maritime border between Mauritania and Senegal.
The contract covers installation of about 75 km outstanding on the two 16-in. export pipelines with field termination assemblies (FTAs) in water depths between 1,500 and 2,800 m, and four 10-in. CRA infield lines with FTAs up to 2 km long in 2,800 m of water.
Allseas will undertake GTA offshore pipelay works early December 2023 using the construction vessel Pioneering Spirit which has 2,000-tonne tension holding capacity. Installation support will be provided by Allseas’ offshore construction support vessel Oceanic.
bp and Allseas commercial and engineering teams designed the installation with a J-lay solution. To install the 10 FTAs, Pioneering Spirit 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.
GTA is 120 km offshore in water depth of 2,850 m and holds estimated gas resources of 15 tcf. Phase 1 will export gas from four subsea wells to an FPSO about 40 km offshore at which the gas will be processed for export to a 2.3-million tonne/year (tpy) floating LNG plant (FLNG Gimi) 10 km offshore (OGJ Online, Aug. 7, 2023).
bp is operator at GTA with partners PETROSEN, Société Mauritanienne des Hydrocarbures (SMH), and Kosmos Energy.