Encana Oil & Gas (USA) has entered into an agreement to sell a portion of its Piceance basin natural gas midstream assets in the US state of Colorado to a private firm for about $590m.

The midstream assets, which include about 260 miles of pipeline and 90,000 horsepower of compression facilities, gather and transport about 500 million cubic feet of gas per day.

These assets serve the company’s Mamm Creek, Orchard and South Parachute production in the area around Rifle, Colorado, about 180 miles west of Denver.

The transaction is expected to close in the fourth quarter of this year and is subject to regulatory approvals and customary closing conditions.