Government of Western Australia Official Site


BHP Billiton considering FLNG to develop WA gas fields

BHP Billiton will examine a floating liquefied natural gas development concept for its deep-water Tallaganda and Bunyip gas resources off Western Australia. The potential FLNG concept is one of the solutions that BHP is committed to studying in accordance with the retention leases over the two discoveries. Retention leases WA-71-R for Bunyip and WA-72-R for Tallaganda were approved by the Australian government on 11th April 2016. The leases are valid for five years, and have near identical work programmes.

The specific FLNG solution that BHP must evaluate is a standalone mini-FLNG facility for the combined Tallaganda-Bunyip resource. Both fields are located in water depths in excess of 1000 metres. Another technology solution the operator will study is extended umbilicals, and subsea compression or separation. BHP is also required to study whether there are any offtake possibilities with its own Macedon gas project, which is an offshore gas field that feeds into a domestic gas plant near Onslow in Western Australia.

The Tallaganda field in 1141 metres of water was BHP’s biggest discovery in 2012 that “opened up a large area of captured acreage with many potential follow-up opportunities”, BHP said at the time. The well was drilled using the semi-submersible Atwood Eagle. Partner Tap Oil has said previously the Tallaganda structure contained a gross recoverable gas resource of about 500 billion cubic feet of gas.

Bunyip lies in water depths of 1190 metres and was discovered in 2014, but its resource size has not been publicised. Meanwhile, BHP is due to drill an exploration well before 26 September 2017 in permit WA-335-P, which previously hosted the Bunyip field. The operator also has some remaining work commitments in WA-351-P, which previously held the Tallaganda discovery.  

The company is due to complete 260 square kilometres of 3D seismic reprocessing as well as geo-logical and geophysical studies by 27 June 2016. Tap has previously referred to the likelihood that monetisation of Tallaganda was likely to be capital intensive and long-term in nature. However, the success of Bunyip would have an impact on the Greater Tallaganda structure.