Quicksilver Resources Inc. (KWK) has executed an agreement to sell an undivided 25% interest in its Barnett shale oil and gas assets for US$485 million to TG Barnett Resources LP, a wholly-owned U.S. subsidiary of Tokyo Gas Co. Ltd.

Quicksilver will remain as operator of the assets. Future development spending will be shared in proportion to each party's working interest in accordance with applicable operating agreements.

The effective date of the transaction is September 1, 2012. Closing is expected to occur on April 30, 2013 and is subject to customary closing conditions.

Proceeds from the transaction are expected to reduce Quicksilver's debt.

Quicksilver was advised by Jason Nye of OBV Group LLC, Prairie Bayou LLC, Credit Suisse Securities (USA) LLC and JP Morgan.

Quicksilver is based in Fort Worth, Texas.