The Crux gas and condensate field is located in the Browse Basin of Australia. With an estimated minimum lifespan of 20 years, the project is expected to produce approximately 2.9 million tonnes per annum (Mtpa) of gas.
The project is a joint venture between Shell Australia (82%), which is also the project operator, SGH Energy (15%), and Osaka Gas (3%).
Offshore project proposal (OPP) of the project was submitted to the National Offshore Petroleum Safety and Environmental Management Authority (NOPSEMA) in 2018. Shell proposes to undertake front-end engineering design (FEED) of the project in 2019, following NOPSEMA approval, and make final investment decision (FID) in 2020.
Crux gas and condensate field location, geology, and reserves
The Crux gas and condensate field is situated in marine waters of the Commonwealth, at a depth between 110m and 170m.
Nexus Energy, as subsidiary of SGH Energy, discovered the Crux gas field within AC/P23 and AC/RL9 blocks.
Shell acquired 82% interest in the gas field from Nexus Energy, while Osaka Gas, through Osaka Gas Crux, purchased 15% interest in the project in August 2007.
The field is estimated to contain 222 billion standard cubic feet (Bscf) of gas and 8.1 million metric stock tank barrels (Mmstb) of condensate, as of 31 July 2014.
Crux Platform details
Crux will act as the primary source of gas supply to the Prelude FLNG project and will be remotely operated from Prelude. The new facility will supply gas and condensate to the Prelude project through a 165km-long export pipeline.
The project will consist of a not normally manned (NNM) platform, in approximately 165m water depth, and an export pipeline system along with topsides processing facilities. Five production wells are proposed to be drilled within the in-field development area, as part of the project.
The in-field development area is spread over approximately 282,000ha, while the export pipeline corridor extends over 32,000ha. The in-field development area will be located 30km from the proposed platform and will incorporate the development of the proposed gas field.
The export pipeline will connect the Crux platform, at a water depth of approximately 170m, to the Prelude FLNG facility, which is located at a water depth of approximately 250m. It will be installed by a pipelay vessel in a proposed route that will be straight and without any seabed obstructions.
The project will also provide for the tie-back of any future subsea developments within the in-field development area to supplement production from the Crux field.
The subsea integration system will include the Crux PLET and Prelude PLEM connecting the export pipeline from the Crux NNM platform to the Prelude facility. Facilities at the integration unit will comprise risers, subsea isolation facilities, a PIG receiver, and associated control systems.
Crux platform development details
The Crux gas and condensate field development is categorized into six stages starting with the development drilling, which includes tie-back and dry tree completion. It is expected to take five years for design and construction.
The next stage will be the installation of platform jacket and topsides, followed by installation and hook-up of export pipeline and subsea integration system to the platform facilities. The field is then proposed to be commissioned and start-up activity will be initiated.
Operations and maintenance are expected to be started in 2025, with decommissioning anticipated to take place in 2045.
Shell Australia has engaged the joint venture of Wood and KBR for undertaking the front-end engineering and design (FEED) for the Crux gas-condensate development project.