The gas-focused Hawkville field accounts for the substantial majority of the writedown, reflecting its geological complexity, product mix, acreage relinquishments and amended development plans - which have pushed out much of the development drilling.

The remainder relates to the impairment of goodwill associated with the Petrohawk Energy acquisition.

The latest hit follows a $US328 million write-down on the Permian field in February and a $US2.84 billion impairment on the gassier parts of the US shale division in 2012.

Following this impairment, BHP's onshore US business will have net operating assets of $US24 billion, which excludes a $US4 billion deferred tax liability.

"The value of this business is supported by ongoing cost reductions and improving well performance which help offset increased commodity price volatility and lower near-term capital expenditure," BHP Billiton Petroleum president Tim Cutt said.

"Consistently positive results from the appraisal and development of the Permian Basin have also unlocked significant value and we now see the ultimate potential of this field at over 150,000 barrels of oil equivalent per day, up from our previous estimate of 100,000boepd.

While the impairment of the Hawkville was disappointing, it did not reflect the quality of the broader onshore US business, according to Cutt.

"The Black Hawk continues to exceed expectations, the Permian offers significant upside across multiple zones and the Haynesville - one of the industry's premier dry gas positions - provides an excellent development option as market conditions improve," he added.

"With industry-leading drilling costs and recoveries, we are well positioned to realise significant value for shareholders as we develop our high-quality resource base."

BHP Billiton plans to invest a scaled back $US1.5 billion in its onshore US assets in the 2016 financial year, which will support a development program of 10 operated rigs.

The company is keen to point out it was not sold a pup when it moved into the US, a move taken during a disastrous expansion phase that includes African coal and global aluminium investments.

At a West Texas Intermediate oil price of US$60 per barrel and a Henry Hub gas price of $US3 per thousand cubic feet, BHP expects its onshore US business to be free-cash flow positive in the 2016 financial year.

The Big Australian will release its production guidance on July 22 and its preliminary financial results on August 25.