Plunging prices forced Lafayette-based Stone Energy to write down the value of its oil and natural gas properties by $351.1 million during the fourth quarter, sending the company to a paper loss of $318.7 million, or $5.76 per share.

Without the write down, Stone earned $2.1 million, or 4 cents per share, compared to $4.1 million, or 7 cents per share a year ago. In the fourth quarter of 2014, the book value of Stone’s oil and gas properties dropped by $304.1 million.

For 2015, the value of Stone’s oil and gas properties fell by $1.36 billion. In 2014, the writedown was $351.2 million.

Stone’s 2015 losses snowballed to $1.1 billion, or $19.75 per share, compared to a loss of $189.5 million, or $3.60 per share, a year earlier.

Without the write downs, Stone lost $28.6 million, or 52 cents per share, for 2015, compared to a profit of $35.2 million, or 65 cents per share, a year ago.