Range Resources Corp. said its estimated unproved resource potential at the end of 2010 reached 35-52 Tcfe, versus 2009’s estimate of 24-32 Tcfe, which was fueled by stronger drilling results. By itself, the resource potential in the Marcellus Shale leasehold jumped to 20-31 Tcfe on higher per/well reserves.

“The unproved resource potential as compared to our year-end 2010 proved reserve base of 4.4 Tcfe reflects the opportunity to grow our proved reserves by roughly 10 times,” the company said. Range drilling results and those by other operators led the company to derisk more of its Marcellus acreage, it said.

“Our outstanding drilling results in 2010 were the primary driver for our 42% increase in proved reserves at year-end 2010,” said CEO John Pinkerton. “This in turn drove up our unproved resource potential to a record level.”

Range also included for the first time unproved resource potential for the Upper Devonian Shale in Appalachia, which lies above the Marcellus Shale on its leasehold, primarily in southwestern Pennsylvania.

“We estimate our acreage holds Upper Devonian Shale unproved resource potential of 10-14 Tcfe,” said the producer. The remainder of the resource potential increase was attributed to the Nora Field in Virginia, as well as in the Permian and Midcontinent basins, where Range has more than 560,000 net acres.

The first well also has been drilled in the Utica Shale of Pennsylvania, which averaged 4.4 MMcfe/d on a seven-day production test. The shale play runs under portions of the Marcellus through several states and into Canada, including parts of Pennsylvania, New York, Ohio, Michigan and Quebec.

“While encouraged by the initial results of our first Utica Shale well, we did not include any resource potential for the Utica Shale in our year-end 2010 estimate,” said company executives. “As Range and other operators drill additional Utica Shale wells in 2011, we expect to gain additional information to assist us in determining the unproved resource potential…”