Offshore installation contractor Allseas has made progress on the installation of the pipeline for Santos’ Barossa Gas Export Pipeline (GEP) project offshore Australia.
Allseas’ Audacia pipelay vessel has installed her largest ever PLET in S-mode, concluding several years of in-house engineering, fabrication and testing, the Swiss-based contractor said.
Due to the weight of the pipeline end termination structure, Allseas’ production crew had to install it separately to the connector head.
Audacia vessels is being supported with four other vessels - Fortitude, Alegria, Felicity and Fortress – which are laying the 262-kilometre-long Barossa GEP.
The 26-inch diameter pipeline will connect the Barossa field development to the future Darwin Pipeline Duplication, transporting natural gas to the Darwin LNG facility in Australia’s Northern Territory.
Australian oil and gas firm Santos, as operator of the Barossa joint venture, reached a final investment decision (FID) for the Darwin Pipeline Duplication Project in Augustu 2022.
To prepare for installing the payload, the in-house design was tested extensively last year, according to Allseas. Offshore crew landed the PLET safely onto its mudmat foundations, installed to pinpoint accuracy earlier in the campaign by Fortitude.
“To make it work, we had to come up with a design that worked in S-mode, so over the stinger, as opposed to J-mode, over the side,” said Dennis Telders, Allseas’ Project Manager.
Allsesas’ scope of work includes the installation of 262-km, 26-inch carbon steel export pipeline with external anti-corrosion and concrete coating, procurement of coated line pipe, and design, fabrication and installation of two PLETs.
Also, the company is in charge of pipeline route optimization and mattress installation at the crossing locations, pre-commissioning activities (flooding, cleaning, gauging and hydro-testing), as well as post-lay and as-built surveys.
As part of the Darwin Pipeline Duplication Project, the Barossa GEP will be extended to the Santos-operated Darwin LNG (DLNG) facility and allow for the repurposing of the existing Bayu-Undan field to Darwin pipeline to facilitate carbon capture and storage (CCS) options.
Gas from the Barossa field, located 300 kilometers north of Darwin, is intended to replace the current supply from the Bayu-Undan facility located in Timor-Leste. First gas production at DLNG using Barossa gas is targeted for the first half of 2025.
To remind, the works on the Barossa gas field pipeline was on pause since November 2023 until January 2024, after an Australian court ruled in favor of Santos in a dispute with an Indigenous man looking to pause the work.