The company has agreed to purchase approximately 85,800 net acres from private owners for $925m, which is located entirely on the Fort Berthold Indian Reservation in the Williston Basin of North Dakota.

The company estimates that these assets represent approximately 185 million barrels of oil equivalent (mmboe) in total net reserves potential in the Middle Bakken and the Upper Three Forks formations.

The assets in the proposed transaction also include 3,300 barrels per day of net oil production from 24 existing wells.

Williams expects to double the current level of drilling activity to six rigs by 2012 and expects the new leases to be producing more than 20,000 barrels per day by the end of 2012.

The sale has an effective date of October 1 and is expected to close by year end, subject to standard closing conditions.