US independent Rex Energy Corporation said today that it has sold a 50% stake in Pennsylvanian assets for $33 million to Williams Energy, in a bid to push forward development of its Marcellus Shale projects.

“Williams will acquire a 50% interest in Rex Energy's leasehold interests in Westmoreland, Clearfield and Centre counties in Pennsylvania, covering around 44,000 acres,” said the company in a statement.

The contract will be paid through a "drill to earn" structure, meaning Willaims will bear the majority of drilling costs in the shared project areas until it has invested $74 million - $33 million on behalf of Rex Energy and $41 million for Williams' 50% share of the wells, Rex said.

Meanwhile, in Butler County project area, Rex announced that it has bought the 50% stake previously owned by its joint venture partner.

“This acquisition gives Rex Energy a 100% interest in these areas and increases the company's position by 6500 net acres to around 21,250 net acres,” said the company.

The new acreage is located close to the company's four producing Marcellus Shale wells, and its natural gas processing plant.