* Sells 91,000 acres of Marcellus lands
* Retains 110,000 acres over the field
* Proceeds to wipe out bank debt (In U.S. dollars unless noted.)
CALGARY, Alberta, May 16 (Reuters) - Enerplus Corp (ERF.TO) agreed to sell its non-operated natural gas properties in the massive Marcellus shale formation in the United States for $575 million in order to pay down debt, the company said on Monday.
Enerplus said the sale includes lands in Pennsylvania, Maryland and West Virginia totaling 91,000 acres and containing an estimated 1.6 trillion cubic feet of gas. The properties produce about 5.4 million cubic feet of gas per day.
The company has been buying up land in the Marcellus field, the largest North American shale gas deposit, since 2009.
The sale locks in a profit for the Canadian producer and leaves it with about 110,000 acres of holdings in the region containing around 2.3 trillion cubic feet of gas.
The proceeds of the sale will more than eliminate the company's bank debt.
"The sale ... captures a significant gain for Enerplus and improves our financial flexibility," Chief Executive Gordon Kerr said in a statement. "In addition, we are retaining a concentrated, meaningful position in this top tier shale play."
The company did not name the buyer.
Enerplus shares fell 6 Canadian cents to C$29.15 on Monday on the Toronto Stock Exchange. The sale was announced after markets closed. ($1=$0.98 Canadian) (Reporting by Scott Haggett; editing by Janet Guttsman)