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.

As part of the approved development, Santos is planning to commence the development drilling and well completions campaign within Commonwealth petroleum production licence NT/L1 in 2023. Drilling and well completions activities may be undertaken at any time of year within the five year activity window. The planned duration for drilling and completion of each well is estimated to take approximately 90 days of continuous well operations (24 hours per day, seven days per week) and the total duration for the planned drilling campaign is estimated to be approximately 2 years.

The ‘Operational Area’ encompasses the entire petroleum production licence. Water depths over the operational area range from approximately 204 m to 376 m. The operational area is approximately 33 km from the Oceanic Shoals Australian Marine Park.

Six subsea production wells are planned to be drilled and completed around the future locations of three subsea production manifolds, with two wellheads adjacent to each manifold. If required, up to two contingency production wells could be drilled and completed at any manifold (eight wells in total). This EP provides for drilling and completing the wells using a semi-submersible Mobile Offshore Drilling Unit (MODU) and light well intervention vessel, and the ongoing management of the complete wells until future commissioning and production phases.

Activities included in the Barossa Development Drilling and Completions Environment Plan are:
• Movement of the MODU within the Operational Area (including entry to and exit from of the Operational Area).
• MODU and vessel commissioning and demobilising activities.
• Deployment and recovery of the MODU anchors and mooring lines.
• Deployment and operation, and eventual removal, of a temporary acoustic survey positioning system.
• Drilling operations, including temporary well suspension and subsequent re-entry as required.
• Well completions, including perforating and well flowback.
• Installation of Christmas trees.
• Contingency activities such as side-track drilling, re-drilling sections, re-spud and abandonment.
• Well intervention.
• Ongoing well inspection, maintenance and management.
• General operations associated with the use of a MODU, vessels, helicopters and remotely operated vehicles (ROVs) within the Operational Area.

A petroleum safety zone will extend in a 500-m radius around the MODU surface location (at each drill centre) and completed subsea well location. During drilling activities, a cautionary zone will be place around the MODU and anchors which may extend up to 2.5 km from the MODU.

The Barossa Development Drilling and Completions Environment Plan will remain valid for 5-years from the date that it is accepted by NOPSEMA, (subject to any requirement for earlier revision under the Offshore Petroleum and Greenhouse Gas Storage (Environment) Regulations 2009).