Anadarko Petroleum Corp., the U.S. oil and natural-gas producer that bought Kerr-McGee Corp. earlier this year, sold fields in Louisiana to Exco Resources Inc. for $1.6 billion to help cut debt.

Exco, which went public in February with billionaire hedge fund manager T. Boone Pickens as its largest shareholder, will almost double its oil and gas reserves. Anadarko is selling assets to pay off debt after buying Kerr-McGee and Western Gas Resources Inc. in August for a combined $22.5 billion.

Anadarko, based in The Woodlands, Texas, is selling the fields to focus on projects that are more attractive, Chief Executive Officer Jim Hackett said in a statement today. The fields are tapped by about 350 wells, and 96 percent of the proved reserves on the properties are in production, Exco said.

``Hackett wants Anadarko to be the fastest-growing production company and is trying to improve his hand,'' said Fadel Gheit, an analyst at Oppenheimer & Co. in New York who rates Anadarko shares ``neutral'' and owns none. ``He's not willing to keep any asset that doesn't have enough growth potential.''

Shares of Anadarko rose 56 cents, or 1.3 percent, to $42.70 in New York Stock Exchange composite trading. The stock has fallen 9.9 percent this year. Shares of Dallas-based Exco jumped $1.06, or 6.3 percent, to $17.90 and have gained 37 percent since the initial offering on Feb 8.