Williams Partners LP has reached agreement with Southwestern Energy Co. to expand the producer’s natural gas gathering and processing services in West Virginia.

Under the deals announced Thursday, Williams would process, fractionate and handle natural gas liquids from Southwestern’s acreage in the Marcellus and Upper Devonian shales. Williams would also provide gathering services for Southwestern in its south Utica Shale dry gas acreage, which the producer recently began developing.

Southwestern has more than 321,500 net acres in southwest Appalachia. It brought its first Utica Shale well online in Marshall County, WV, earlier this year and completed a second in Washington County, PA, over the summer. The company has been tight-lipped about its nascent Utica program, but the deal with Williams dedicates 71,500 acres in Marshall and Wetzel counties to gathering services.

Southwestern also has committed to 660 MMcf/d of processing capacity to serve another 135,000 acre area in Marshall and Wetzel counties. As a result, Williams plans to expand its 200 MMcf/d Oak Grove processing facility in Marshall County beginning early next year, said spokesman Joe Horvath. The plant has the ability to be expanded by another 1.8 Bcf/d. 

Williams’ northeastern midstream services are continuing to grow. The operator expanded its ownership in the Bradford Supply Hub in northeast Pennsylvania earlier this year in a deal with Anadarko Petroleum Corp.’s majority owned Western Gas Partners LP. The company said Thursday that downstream gas connections are being added in West Virginia to TransCanada Corp.’s Leach and Mountaineer Xpress projects to increase market access.

Southwestern has been busy on the midstream front, announcing an agreement with Boardwalk Pipeline Partners LP earlier this month to restructure firm transportation agreements in the Fayetteville Shale.