Crestwood Midstream Partners (CLMP) and Crestwood Holdings Partners said their newly formed joint venture, Crestwood Marcellus Midstream has completed the acquisition of Antero Resources Appalachian Corporation’s Marcellus Shale gathering system assets in West Virginia, US for $375m.

The deal will have a January 1, 2012 effective date.

The acquired assets include 34 miles of low pressure gathering pipelines located in Harrison and Doddridge Counties, West Virginia, which are currently gathering 230 million cubic feet per day from 63 existing horizontal Marcellus Shale wells.

An additional 51 wells are expected to be drilled and connected during this year.

The gathering pipelines deliver Marcellus Shale production to various regional pipeline systems including Columbia, Dominion and Equitrans and later this year will begin deliveries to intermediate systems that will connect to MarkWest Energy Partners’ Sherwood Gas processing plant, expected to be operational in the third quarter of 2012.

Crestwood and Antero have also inked a 20-year gas gathering and compression agreement, which will provide for an area of dedication of about 127,000 gross acres, or 104,000 net acres.

In addition, Antero has provided for annual minimum volume commitments and a right of first offer on future development on acreage adjacent to the area of dedication in Doddridge County.