For now, state geologists are finished with their research in central North Carolina.

After studying 59,000 acres in the Deep River basin for 15 years, they have concluded that Lee, Chatham and Moore counties could produce enough natural gas from shale to make North Carolina self-sufficient for 40 years at current levels of consumption.

"That's what we think," said Kenneth Taylor, chief of the N.C. Geological Survey. "We could become a net exporter."

The geologists recently sent their findings to the U.S. Geological Survey in Denver, which is being asked to assess the full potential of the Sanford sub-basin, a shale formation near the center of the Deep River basin. The sub-basin has the potential to hold the state's richest natural gas deposits, though exploration will continue elsewhere in the state.

Taylor said an assessment and fact sheet is expected from the U.S. Geological Survey by July.

The assessment would then be made available to energy companies eager to explore and begin commercial gas production in the sub-basin.

The findings could one day lead to riches for landowners - many of whom already have signed land-lease deals with the energy companies - and huge revenues for the state.

"The benefits from revenues that the state of North Carolina would gain from a productive natural gas industry would be immeasurable," said state Rep. Michael Stone of Lee County. "Citizens owning property with natural gas will benefit directly, while all people in our area will benefit indirectly."

But with the potential rewards come significant risks. The process of extracting natural gas from shale combines a relatively new technology, horizontal drilling, with a controversial process called fracturing - or fracking - that involves using chemicals and vast amounts of water to force natural gas out of the shale.

Earlier this month, a Duke University study concluded that fracking appears to elevate methane levels in groundwater wells near gas drilling sites. New York has put a moratorium on the practice.

Fracking and other controversies surrounding natural gas excavation have not gone unnoticed in North Carolina.

"We have to protect the environment in which we live and not at the expense of having another fuel source," said Russ Patterson, chief geologist with Patterson Exploration Services of Sanford. "We live here. We live on planet Earth. We have to take care of it."

Before any drilling could occur in North Carolina, state laws would have to change. The state does not allow horizontal drilling or fracking, though bills recently introduced in the General Assembly by Stone and other lawmakers could change that.

Although drilling still may be years away, one thing is becoming clear: North Carolina has an abundance of high-quality natural gas.

"The first thing about it: Do we have a total petroleum system?" Taylor asked. "Do you have rocks with high enough total organic carbon above a certain value. Above 1.4 percent? Our samples are running 3, 5, 15 percent hydrocarbon.

"It's good stuff."