Summit Midstream Partners said Wednesday that it will buy Denver-based Bear Tracker Energy for $513 million in a deal that includes a natural-gas processing plant and 84-mile gas gathering system in Weld County.

The Niobrara Gas Gathering System, under construction in Hereford near the Wyoming border, will serve gas production by EOG Resources. The cryogenic processing plant will have a capacity of 20 million cubic feet of gas per day.

The infrastructure is expected to be completed in the second quarter, Bear Tracker CEO Robert Clark said.

Dallas-based Summit Midstream, which has an office in Denver, said it expects the acquisition to close in the first quarter subject to regulatory approval.

The deal also includes privately held Bear Tracker's assets in the Williston Basin in North Dakota.

"This acquisition provides us with a significant presence in two of the most prolific and highest growth unconventional crude oil basins in North America," Summit Midstream CEO Steve Newby said.