Australia's Woodside Energy Group (ASX: WDS ) said today that it would book a nearly $4.4 billion expense this year, as changes in its asset depreciation calculation method outweighed a tax benefit and a reversal of an impairment charge. The country's biggest independent gas producer said it had reviewed the methodology it follows to calculate depreciation of its oil and gas properties, after taking into account the scale of its portfolio since acquiring BHP Group's petroleum assets. Woodside's statement: Asset value review: impairment reversals and deferred tax asset recognition Woodside has undertaken a review of the year-end carrying values of its assets in accordance with its accounting policies and the accounting standards.