Construction vessels gear up for work in Australia

Australia's offshore oil and gas industry has been busy in 2023, and continues to be bustling in 2024, as several key projects take the spotlight. Construction on these projects is in full swing, heralded by the arrival of numerous offshore construction vessels into the country, ready to start work.

Woodside Energy's Scarborough

Development of Woodside's Scarborough located offshore Western Australia involves installation of floating production unit (FPU) with eight wells drilled in the initial phase and 13 wells drilled over the life of Scarborough field. Gas will be processed at the second liquefied natural gas (LNG) train (Pluto Train 2) at existing Pluto LNG onshore facility through a new approximately 433 km trunkline.

Various international installation contractors all have a piece of the pie for this major project. Subsea 7 is working on the engineering, procurement, construction, and installation (EPCI) contract for the subsea umbilicals, risers, and flowlines (SURF) scope. The contractor has deployed its pipelay vessel Seven Oceans and DP3 heavy construction support vessel Seven Oceanics for installation works since 2023, with work continuing into 2024.

Meanwhile, Saipem's DP3 heavy lift pipelay vessel Castorone has undertaken the installation of 400 km trunkline, complemented by Saipem's heavy lift pipelay vessel Saipem Endeavour's successful 33 km nearshore segment in December 2023. However, pipelay works at Scarborough were temporarily halted following an offshore trunkline installation incident on January 30. An initial assessment revealed a software anomaly leading to a tensioner failure and subsequent pipeline buckling on the seabed. Castorone has since resumed pipelay operations at Scarborough field following recent approval from Australia's National Offshore Petroleum Safety and Environmental Management Authority (NOPSEMA).

Ready to join the vessel operations in Australia is McDermott's heavy lift pipelay vessel DLV 2000, currently sailing to Dampier, with an expected arrival in early March. DLV 2000 will initially mobilize to Santos-operated Campbell field for an anticipated 14-day decommissioning project before proceeding to Woodside's Scarborough project for FPU foundation and mooring installation works.

Santos' Barossa

The Barossa development includes a turret-moored floating production, storage, and offloading vessel with a processing capacity for up to 800 MMscf/d of gas and 11,000 b/d of condensate, subsea production system, supporting in-field subsea infrastructure and a subsea gas export pipeline.

Following the recent lifting of an injunction by the Federal Court of Australia in January 2024, Santos has resumed pipelaying activities at Barossa, having previously halted pipelay work south of kilometre 86 (KP86) point along the gas export pipeline (GEP). Allseas' pipelay vessel Audacia and DP3 heavy construction support vessel Fortitude have been undertaking the installation of the 262 km 26-inch GEP. This pipeline connects Barossa field to Darwin liquefied natural gas facility via the Darwin Pipeline Duplication (DPD) project. Approximately 131 km of the pipeline has been installed, and Allseas is expected to complete the pipelay scope in the second quarter of 2024.

Active decommissioning projects in Australia

Several active decommissioning projects are also currently underway in Australia, including Cooper Energy's Basker-Manta-Gummy (BMG) site in the Gippsland Basin. Helix Energy Solutions' DP3 semisubmersible well intervention vessel Q7000 has been deployed to BMG fields since late December, focusing on the plug and abandonment of seven subsea wells in the first phase of decommissioning activities. Meanwhile, field decommissioning operations at Woodside's Stybarrow and Griffin fields are supported by two DP2 heavy construction support vessels: DOF's Skandi Hercules for Stybarrow and TechnipFMC's Deep Orient for Griffin, operating concurrently, with completion expected by the end of 2024.

Figure 1: Active offshore construction vessel working in Australia.

Figure 2: Offshore construction vessel in Western Australia region

This article was published by S&P Global Commodity Insights and not by S&P Global Ratings, which is a separately managed division of S&P Global.