The company will pay about $338m for these assets, with an additional $15m to be paid to Frontier if certain operational objectives are met within six months of the closing date.

The Frontier Fayetteville assets consist of about 127 miles of high pressure and low pressure gathering pipelines with capacity of about 510 million cubic feet per day (mmcf/d), treating capacity of about 165mmcf/d and about 35,000 hp of compression.

The Frontier Granite Wash assets currently consist of a 28-mile pipeline system and a 36mmcf/d cryogenic processing plant in the Texas Panhandle.

Crestwood plans to install a second processing plant with 60mmcf/d of capacity that is expected to be in service by the end of this year.

The acquisition is expected to close in the second quarter of 2011, subject to regulatory approval.