Official proposals for the ConocoPhillips-led consortium’s Barossa and Caldita natural gas fields’ development in the offshore Bonaparte basin 300 km north of Darwin in the eastern Timor Sea have been made public by the Australian National Offshore Petroleum Safety & Environmental Management Authority (NOPSEMA).
The development concept includes a permanently moored floating production, storage, and offloading facility, subsea production system, and supporting in-field subsea systems in Barossa field in retention lease NT/RL5.
The FPSO will separate gas and condensate piped from the field. Condensate will then be exported directly via offtake tankers while the dry gas will be transported via subsea export pipeline for processing onshore.
The document, which NOPSEMA has posted for public comment, notes that no commercial arrangements are yet in place, however it is proposed to connect the subsea gas line to the existing Bayu-Undan field pipeline that supplies ConocoPhillips’s LNG plant at Wickham Point near Darwin.
The intention is for gas from Barossa to replace the existing supply from Bayu-Undan following its anticipated depletion in 2022.
The new gas pipeline route has not been finalized, but a corridor has been identified for the purposes of the early stage of the group’s offshore project proposal (OPP) to enable flexibility for placement of the line once further engineering and environmental investigations have been completed.
The development concept also has allowed for the potential future staged development of smaller Caldita field to the south in retention lease NT/RL6.
The Barossa project will produce an anticipated 3.7 million tonnes/year of LNG along with 1.5 million bbl/year of condensate. Project life is expected to be 20 years and the proposal calls for it to come on stream in 2023.
Barossa field was discovered in November 2006 in 320 m of water. Appraisal wells at the field have recorded as much as 16% carbon dioxide content, which will need to be dealt with in the gas processing stage.
Caldita, 20 km southwest in about 150 m of water, was found in September 2005.
The OPP covers all stages of the project from the phased development drilling program, installation, pre-commissioning and commissioning of the FPSO, and subsea systems including the pipelines and fibre optic cable, the operations phase, and finally plans for the eventual decommissioning.
The document will be open for public comment until Sept. 6.
Interest holders are operator ConocoPhillips 37.5%, South Korean combine SK E&S 37.5%, and Adelaide-based Santos Ltd. 25%.
