The assets include 12,900 net acres, certain producing Marcellus Shale wells and associated mid-stream assets, and the transaction is expected to close in September 2010.

Sumitomo will pay approximately $88.4m in cash upon closing and an additional $52m in the form of a drilling carry, and Rex Energy will continue to serve as the operator of its Butler County, Pennsylvania project area.

In addition to funding its own share of drilling obligations, Sumitomo will fund 80% of Rex Energy’s remaining share of drilling and completion costs until the $52m drilling carry is fully utilized.