HOUSTON (Reuters) - Exxon Mobil Corp XOM.N boosted its 2017 capital budget on Tuesday on a bet that oil prices have stabilized, but posted its lowest quarterly profit since 1999 as it took a $2 billion charge against the value of natural gas reserves from its buyout of XTO Energy.

The logo of Exxon Mobil Corporation is shown on a monitor above the floor of the New York Stock Exchange in New York, December 30, 2015. REUTERS/Lucas Jackson/File Photo

The world’s largest publicly traded oil producer wrote down the book value of part of its North American natural gas and crude reserves, some of which were acquired in 2009’s all-stock buyout of XTO Energy, a deal worth roughly $30 billion at the time.

After conducting an annual asset review, Exxon said the value of some reserves in North America’s Rocky Mountain region should be lowered due to weak performance and its own tepid outlook on the potential for future commodity price rises. Exxon declined to provide its internal forecast for oil and gas prices.

Exxon will report estimates for the value of its proved reserves in February. The $2 billion impairment charge likely will reduce the value of the proved reserves.

Wall Street traders expect oil prices to stay near their current range, between $54 and $55 per barrel, for several years and for natural gas prices to remain near their current level, about $3.13 per million cubic feet. <0#CLCAL:> NG12Mst

Exxon also said it will increase spending to about $22 billion this year from $19.3 billion in 2016. The move came after peers Chevron Corp CVX.N, Hess Corp HES.N and other oil producers boosted their capital budgets for the year.

The 14 percent boost in capital expenditures and the writedown reflect a delicate balancing act by oil and natural gas companies in an era of extreme volatility after a two-year price rout.

The higher spending is not due to rising prices for oilfield contract work or other services, Jeff Woodbury, Exxon’s vice president of investor relations, said on an earnings conference call with investors.

“It is, by an large, a function of activity level” increasing, Woodbury said.

Exxon’s announcement came after the company posted a better-than-expected quarterly profit, helped by rising oil prices and lower costs.

The results reflected the slow and steady improvement in the global oil and gas industry as commodity prices inch higher after a two-year rout.

The quarterly report was Exxon’s first under Chief Executive Officer Darren Woods. Rex Tillerson, the former CEO, has been nominated by U.S. President Donald Trump to be secretary of state and is awaiting confirmation.

Fourth-quarter earnings fell to $1.68 billion, or 41 cents per share, from $2.78 billion, or 67 cents per share, in the year-ago period.

Excluding the $2 billion writedown, Exxon earned 90 cents per share. By that measure, analysts expected 70 cents per share, according to Thomson Reuters I/B/E/S.

Production fell 3 percent to 4.1 million barrels of oil equivalent per day.

Earlier this month Exxon said it would pay up to $6.6 billion to double its holdings in the oil-rich Permian Basin of west Texas, the largest oil field in the United States.

Shares of Texas-based Exxon fell 1.7 percent to $83.40 in afternoon trading.