Crestwood Midstream Partners LP late Monday agreed to pay $90 million to buy some of Devon Energy Corp.’s midstream assets in the Barnett Shale and to process the producer’s natural gas output from 20,500 dedicated acres, now estimated at 95 MMcf/d, over a 20-year period.

The assets to be acquired include a 74-mile low-pressure natural gas gathering system, a 100 MMcf/d cryogenic processing facility and 23,100 hp of compression equipment in the western portion of Johnson County, TX. Devon’s pipeline system and processing plant, built in 2006, are adjacent to Crestwood’s Cowtown gathering system, which includes the Cowtown and Corvette gas processing plants with a combined capacity of 325 MMcf/d.

The Cowtown system and Devon’s Johnson County system now are interconnected, and Crestwood has processed gas volumes for Devon in the past. When the transaction is completed, which is expected by the end of September, Crestwood plans to consolidate the systems and process all of Devon’s gas in its plants. “This integration plan is expected to result in future cost savings for Crestwood and provide Devon with lower wellhead pressures, higher natural gas liquids (NGL) recoveries and expanded market outlets,” Crestwood said.

Because of the “liquids-rich quality of the natural gas production in this portion of the Barnett Shale, Devon has maintained an active drilling and development plan for the West Johnson County area in 2012 and expects to continue to further develop the dedicated properties in 2013,” said officials. Devon now produces from 230 wells in the western part of Johnson County.

“The acquisition allows us to consolidate the two systems, optimize the available capacity in Crestwood’s existing high-recovery cryogenic processing plants and provides long term benefits to Devon through lower wellhead pressures, higher NGL recoveries and expanded marketing options for their natural gas and NGL production,” said Crestwood CEO Robert Phillips. “The transaction…allows us the option of leaving the West Johnson County plant in place to handle future production requirements or to move it to another rich gas region such as the Marcellus/Utica, Granite Wash or Avalon Shale plays, where we are currently working on new rich-gas development opportunities.”