DORIS provided CAPEX and OPEX optimisations for BONAPARTE FLNG
The development concept consists of two integrated segments:
- Upstream: Fields could be produced via Subsea wellhead and/or platforms. A Central Processing Platform might be used, located on Petrel field.
- Midstream: A FLNG could be used, permanently (turret) moored with an option for disconnectability under passage of cyclones. Offloading will be side-by-side.
The FLNG vessel could be redeployed to other areas at the field end-of-life. The proposed floating liquefaction plant will utilize the gas from the Petrel, Tern and Frigate natural gas fields to produce LNG and the FLNG is anticipated to be located in the Bonaparte Basin around 300 km west of Darwin.
The feed gas (natural raw gas), directly produced from the fields has to be treated to remove liquids (C5+, formation water, hydrate inhibitors, corrosion inhibitors and solid particles), the acid gases (CO2 and H2S traces) and to dehydrate the treated gas to reduce the water content to a very low level and to extract any mercury content. LNG (C3+) recovery unit may be required to reach the LNG quality requirements depending on the richness of the feed gas. One LNG liquefaction process, i.e. Double Nitrogen Expansion Loop Process (open art), is considered for the production of LNG.
Some of the products (LNG) have to be stored on board and periodically offloaded to specialized vessels.
Services provided by DORIS:
Midstream Pre-FEED Studies
Design Facilities Study covering :
- Field production operational requirements
- Mooring system
- Turret (permanent moored / disconnectable, internal /external)
- Hull design and storages
- Raw gas treatment (three different feed-gas compositions)
- Liquefaction Processes
- Split of processes systems between upstream & midstream (four options)
- Utilities and products offloading systems
- CAPEX and OPEX estimations
- Water depth: 100 m
- Feed gas input : 360 MMscfd versus 540 MMscfd
- Production: 2 MTPA versus 3 MTPA LNG
- storage capacity : 210 000 m3
- Condensate storage capacity: 40 000 m3
- Hull size: 345 m length x 65m breadth x 35 m depth
- Living quarters: 200 persons /130 permanent
- FLNG total dry weights: ranging from 166 000 t to 177 500 t
- Hull outfitting, LQ turret, mooring etc. dry: 37 145 t
- LNG offloading in side-by-side configuration
- Topsides dry weights: ranging from 30 000 t to 53 000 t