Devon Energy Corp. announced that it has completed its previously announced $5 billion acquisition of Grayson Mill Energy. The Oklahoma City-based oil and gas company said the acquisition adds a high-margin production mix that enhances Devon’s position as one of the largest producers in the U.S. The transaction transforms the company’s Williston Basin business, with the addition of 307,000 net acres, 500 undrilled gross locations and 300 high-quality refrac candidates.