Anadarko Petroleum Corp. reported its biggest quarterly loss in more than a decade after writing down the value of a single field in Utah by $3.7 billion.

Falling commodity prices forced the Woodlands, Texas-based company to recognize a non-cash loss in the value of the Greater Natural Buttes field, John Christiansen, a spokesman for Anadarko, said in a phone interview Monday. While the holdings still constitute “a quality asset,” the value of the natural gas reserves in the field fell as prices declined, he said.

Greater Natural Buttes was originally envisioned as a $10 billion project that involved drilling almost 4,000 wells. The company acquired the 237,000 net acres in the Uinta basin area when it bought Kerr-McGee Corp. in 2006.

Anadarko now operates 2,800 wells in the area and drilled 133 wells in 2014, slowing activity as gas prices fell, according to its annual report. The company had envisioned drilling 400 new wells a year.

Excluding one-time items, the energy producer lost 72 cents a share in the first quarter, 7 cents more than the average of 33 analysts’ estimates compiled by Bloomberg. Its net loss widened to $3.27 billion, or $6.45 a share, from $2.67 billion, or $5.30, a year earlier, Anadarko said in a statement.

The results were released after the close of regular trading in New York. Anadarko gained 12 cents to $93.85 at 5:29 p.m. The shares have climbed 14 percent this year.