Plunging energy prices slashed the value of Stone Energy Corp.’s oil and gas properties and sent the Lafayette-based company to a first-quarter paper loss of $327.4 million, or $5.93 per share.

The first-quarter results included a $314.5 million after-tax write-down of its oil and gas properties. Without that charge, Stone lost $12.9 million, or 23 cents per share, on revenue of $148.2 million. A year earlier, the company reported a profit of $25.9 million, or 52 cents per share, on revenue of $222.6 million.

Analysts surveyed by Zacks Investment Research had forecast a loss of 14 cents per share. Stone reported its earnings after the market closed Monday.

Stone sold its oil for an average of $66.28 per barrel, $20.97 more than the actual market price — during the first quarter. Stone accomplished this through hedges that allowed the company to sell part of its production for much higher prices. A year earlier, Stone realized an average oil price of $97.52 per barrel.

Stone also saw big drops in the average price of natural gas and natural gas liquids, which include propane, butane and ethane, to $2.54 per thousand cubic feet and $18.11 per barrel, respectively. A year earlier Stone got $4.46 per thousand cubic feet of gas and $54.84 per barrel of natural gas liquids.

Stone slashed capital expenditures to $113.8 million, compared to $254.1 million a year ago. The company’s 2015 capital expenditure budget of $450 million assumes planned sales of minority working interests in certain assets.