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Barossa Subsea Infrastructure Installation Project

Activity type Construction and installation of a facility
Activity subtypes
Lifecycle Classification Operation & Production
Submitted by Santos NA Barossa Pty Ltd
Submission date 18 October, 2023
Subtype New
Decision date 02 February, 2024
RMS ID 7599
Status Finalised
Outcome Accepted
Link to previously accepted EP
Michael Marren
Phone: 08 9266 0542
Location map (click to enlarge)
Location map - Activity: Barossa Subsea Infrastructure Installation Project (refer to description)

The Barossa Development is an approved offshore natural gas and condensate development proposed to backfill gas supply to the existing Darwin LNG (DLNG) facility at Wickham Point. Natural gas would be extracted from the Barossa field, located in Commonwealth waters approximately 285 kilometres offshore north-north west from Darwin, and transported via gas pipeline (Gas Export Pipeline (GEP) and Darwin Pipeline Duplication (DPD)) to the existing DLNG facility. Santos NA Barossa Pty Ltd (Santos), is the Operator of the Barossa Development, on behalf of co-venturers SK E&S Australia Pty Ltd, JERA Barossa Pty Ltd and Santos Offshore Pty Ltd, with first gas production targeted for the first half of 2025.

The Barossa Development is described in the Barossa Development Area Offshore Project Proposal (OPP), which was accepted by the National Offshore Petroleum Safety and Environmental Management Authority (NOPSEMA) in March 2018.

Santos proposes to install a part of the Barossa Gas Project relating to the Barossa subsea umbilicals, risers and flowlines (SURF), manifolds and floating production, storage and offloading (FPSO) moorings installation (collectively referred to as subsea infrastructure) and pre-commissioning activity. The Barossa Subsea Infrastructure Installation EP covers the above scope.

The total duration of the SURF campaign is estimated to be approximately nine months, subject to factors including vessel availability, operational efficiencies and weather conditions. This campaign is currently planned to commence between Q4 2023 and Q4 2025, subject to obtaining regulatory approvals. The preservation phase commences on completion of installation of key infrastructure and pre-commissioning activities. The preservation phase is designed to maintain the integrity of the infrastructure. The preservation phase for the subsea infrastructure will last up until commissioning, i.e. upon the commencement of activities under the Barossa Production Operations EP.

The operational area covered under Barossa Subsea Infrastructure Installation EP is the area within which all planned activities will occur. The operational area is defined as approximately 10 kilometres by 13.5 kilometres. Figure 1 shows the proposed location and operational area of the SURF and moorings infrastructure.

Activity vessels and helicopters within the operational area are considered part of the activity under the Barossa Subsea Infrastructure Installation EP.

Activities included in the Barossa Subsea Infrastructure Installation EP are summarised below:

• Underwater acoustic positioning – using long baseline and / or short baseline acoustic positioning to accurately install and position subsurface infrastructure
• Underwater surveys – undertaking pre-lay surveys using a multibeam echo sounder, side-scan sonar and magnetometer to identify any potential obstructions before installing infrastructure
• Mooring installation – installing a mooring system consisting of mooring lines, suction anchors and a submerged turret buoy
• Flowline lay – installing flowlines and pipelines using a reel-lay vessel
• Manifold installation – installing manifold foundations and a manifold via the vessel crane and ROV to position and orientate the manifold
• Riser installation – using vessels to instal the riser and riser tether base
• Umbilical and flying lead installation – installing three static umbilicals on the seabed, which will be lowered by the construction vessel and two dynamic umbilicals pulled in and hung off the STP buoy
• Vessel activities – installation vessels (reel lay vessels), construction vessels and other support vessels will be used during the activity
• Pre-commissioning activities – including flood, clean, gauge and pressure testing, dewatering, preconditioning, nitrogen packing, flushing and hydrostatic leak testing of equipment
• Unplanned and non-routine inspection, maintenance and repairs will be undertaken as required.

Other Details
Locations Northern Territory
Commonwealth waters adjacent to Northern Territory
Titles (or other instruments) NT/L1
Current Documents (Finalised)
EP Document

OPEP Document

Location map

Statement of reasons

Previous EP Documents (Under assessment)
EP Document

OPEP Document

Location map