The Barossa offshore project is planned to be produced through a floating, production, storage, and offloading facility. Credit: ConocoPhillips Australia Exploration.
The offshore project is located in the Bonaparte Basin in the Timor Sea. Credit: Wikimedia Commons.
The Barossa offshore development project is expected to replace production from the Bayu-Undan field. Credit: ConocoPhillips Australia Exploration.

The Barossa project is a gas and condensate field located in the Bonaparte Basin of the Timor Sea, offshore Australia, at water depths between 130m and 350m.

The field is being developed along with the nearby Caldita field under the Barossa offshore development project.

The field is operated by Santos with a 50% working interest. Other partners in the project are SK E&S (37.5%) and JERA (12.5%).

Santos acquired ConocoPhillip’s 37.5% stake in the project in October 2019 and sold a 12.5% interest to JERA in April 2022.

Environment Plan (EP) Revision 3 of Barossa Drilling and Completions was approved in March by the National Offshore Petroleum Safety and Environmental Management Authority (NOPSEMA). The country’s Federal Court rejected the Drilling EP in September 2022.

The first gas from the offshore project is expected to be achieved in the first half (H1) of 2025 with an estimated annual production rate of 3.4 million tonnes of liquefied natural gas and 1.5 million metric barrels of gas.

The project is expected to have a life of approximately 25 years from its first gas production.

Location details

The field is located within the Bonaparte Basin in the petroleum retention lease NT/RL5. The site lies in Commonwealth waters, approximately 300km north of Darwin in the Northern Territory of Australia and 100km north of Tiwi Islands.

Barossa and Caldita discovery

Barossa was discovered in 2006 with the drilling of the Barossa-1 exploration well to a depth of 4,310m.

Two drill stem tests were conducted on the well, which confirmed the presence of gas. The flow rate was 30.1 cubic feet a day in one test, while it was 0.8 million cubic feet a day in the other.

The Caldita field was discovered in 2005 by the Caldita-1 well and was subsequently appraised by the Caldita-2 well in 2007.

Appraisal on Caldita-Barossa

The Barossa field has been appraised by a total of five wells. The first three wells, Barossa-2, Barossa-3, and Barossa-4, were part of a three-well appraisal programme that was completed in 2015.

Barossa-2 struck 88m of net pay in the Upper Elang, Lower Elang, and Plover reservoirs, while Barossa-3 encountered 104m of net pay and Barossa-4 further confirmed the potential of the field.

A second appraisal programme consisting of two wells, Barossa-5 and Barossa-6, was completed in June 2017. The two wells confirmed reservoir productivity and provided critical data for field development planning.

Barossa-6 struck gas and condensate in the Elang reservoir located between depths of 4,103m and 4,144m. Tests conducted on the well resulted in a flow rate of 65 million metric standard cubic feet a day.

Barossa project development details

The proposal for the development of the Barossa field was accepted by the NOPSEMA in March 2018. The final investment decision of $3.6bn on the project was made in March 2021.

The field is proposed to be developed in two phases. The first phase involves six directionally drilled production wells from three subsea manifolds. The second phase is expected to pick up eight years after the first oil is produced. It will add four additional production wells via two subsea manifolds.

The project is planned for development via a permanently moored floating, production, storage, and offloading (FPSO) facility. The development also includes a subsea production system, in-field subsea infrastructure, and a gas export pipeline.

The natural gas and condensate from the field will be separated on the FPSO. Dry gas will be transported onshore via an export pipeline while condensate will be directly exported via tankers.

The FPSO will feature a newly built hull based on the Rapid Framework design by BW Offshore. The design enables the accommodation of the most advanced topsides. It will have the capacity to process up to 800  million metric standard cubic feet a day of gas and 11,000 barrels of stabilised condensate a day.

A fibre-optic cable is scheduled to be laid between the FPSO and Darwin to enable remote operation of the facility.

Darwin pipeline duplication details

The dry gas produced from the FPSO will be transported onshore to the Darwin Liquefied Natural Gas facility via a 502km subsea gas export pipeline, which is a duplication of the Darwin pipeline.

The final investment decision for the development of the Darwin pipeline duplication project was made in August 2022. The pipeline will be laid parallel to the existing Bayu-Undan to Darwin pipeline. The gas pipeline will be developed approximately 100km within Northern Territory waters and 23km in Commonwealth waters.

The gas export pipeline will be tied in with the Bayu-Undan to Darwin gas export pipeline.

The Bayu-Undan carbon capture and storage project having an initial injection and storage capacity of approximately 2.3 million tonnes per annum (mpta) of carbon dioxide from the field is also planned to be developed.

LNG sales and purchase agreements

Santos signed a supply and purchase agreement with Diamond Gas International, a subsidiary of Mitsubishi, in December 2020. Under the terms of the agreement, Santos will supply 1.5mtpa of liquified natural gas (LNG) from the project for ten years through its equity share in the field.

Project financing

The project secured $1.15bn in debt financing for the construction of the FPSO from a syndicate of nine international banks in August 2021. The lenders include Korea Development Bank, United Overseas Bank, Clifford Capital, MUFG Bank, Natixis, Oversea-Chinese Banking, Sumitomo Mitsui Banking, ABN Amro, and Cooperative Rabobank.

The project also has financial support from the Export-Import Bank of Korea, Korea Trade Insurance, and Japan Bank for International Cooperation.

Contractors involved in the Barossa project

BW Offshore, a floating production services provider, was awarded a contract to lease and operate the Barossa FPSO for a period of ten years in March 2021. The contractual scope includes the engineering, procurement, construction, installation, and operation of the FPSO.

BW Offshore subcontracted shipbuilding and repairing company, Samkang M&T, now known as SK Oceanplant, for the fabrication of the hull. National Oilwell Varco, an offshore technology service provider, was also subcontracted for the supply of the submerged turret production system.

Other subcontractors to BW Offshore include Dyna-Mac Engineering Services, a construction company, for topside module fabrication, and FG Industry, an offshore engineering company, for detailed engineering and 3D modelling for the hull.

Subsea 7, an offshore engineering company, was contracted to provide transportation and installation services for the subsea umbilicals, risers, flowlines, and in-field flowlines in March 2020. The scope of work includes project management, engineering, procurement, fabrication, transportation, installation, and precommissioning services. Aker Solutions will supply the umbilicals while National Oilwell Varco will supply the flexible risers.

Allseas, a pipelay and subsea construction company, was contracted to provide engineering, procurement, transport, and installation services for the gas export pipeline for the project in October 2019.

Allseas subcontracted a joint venture between Van Oord, a marine contractor, and DEME, an offshore contractor, to provide trenching, pipe pull operations, and rock placement work services for the Darwin pipeline duplication project in September 2022.

Shawcor, a material sciences company, was also subcontracted by Allseas to provide anti-corrosion, internal flow coat, and concrete weight coatings for the Darwin Pipeline Duplication in September 2022.

Technip FMC, an energy technology company, was awarded the contract to supply subsea production systems for the Barossa field in May 2019. The scope of the contract included engineering, design, and fabrication of wellheads, manifolds, and control systems along with the installation and commissioning support.

MODEC International and a consortium of TechnipFMC and Samsung Heavy Industries were awarded separate engineering design contracts for the FPSO in June 2018.

Intecsea, a subsidiary of Worley Parsons, was awarded the front-end engineering design contract for the subsea infrastructure, including umbilicals, flowlines, risers, and gas export pipeline.