Beach recorded a $449 million impairment in June, at the time assuming the oil price would be $US62.50 per barrel for 2016, rising to $US90/bbl in 2019, but those assumptions now seem hopelessly optimistic, and oil has fallen 40% in January alone.
It could mean Beach's 2015 writedowns top $1 billion.
With the company's development plans also being curtailed acting CEO Neil Gibbins said the company was reviewing its assumptions and would announce the final impairment on February 26.
He said the writedowns would be predominantly in relation to non-operated Cooper Basin oil and gas assets, and would likely be between $450-650 million on a pre-tax basis.
He said the non-cash charges would not impact the underlying financial position of the company, although it will affect whether the company turns a profit, and how big that profit or loss is.
"During these challenging times it is extremely pleasing to demonstrate Beach's ability to live within its means and maintain financial strength," Gibbins said.
"Despite lower oil prices, over the past six months we have held our net cash position relatively constant, secured increased debt financing facilities on improved terms, and identified up to $40 million of second half 2015-16 savings and deferrals in our capital program.
"Operationally, we continue to perform well. Production levels were maintained during the second quarter of 2015-16, giving us greater confidence in our full year guidance, and recent infrastructure projects have delivered results better than expected."
The company also used the announcement to narrow its production guidance from 7.8-8.6MMboe to 8-8.6MMboe.
The reduced capital expenditure guidance of $180-210 million from $240-270 million, with the biggest savings being in its Cooper Basin heartland with 10 wells being dropped, deferred completions and connections, deferral of the Bauer facility upgrade and non-critical projects and a reduction in work in the Santos-operated blocks.
Gibbins said Beach had a resilient business model that helped it navigate current challenges. He will deliver the news, and step down as acting CEO in July, making way for Oil Search commercial manager Matthew Kay, who has been appointed to fill the vacancy after months of uncertainty.
Beach had $164 million in cash at December 31, $150 million drawn debt and $350 million in undrawn facilities.
Its shares last traded at $0.387, half where they were six months ago.
