Most sites, which can have as many as four wells, need more than a megawatt of electricity to power the submersible pumps that push oil and water to the surface.
“That's quite a lot of power,” Matlock said.
Traditionally diesel-fueled generators have been used, but that is an expensive option because the fuel can cost at least $100,000 a month.
Matlock said Devon began looking into replacing diesel with natural gas last fall.
Officials met with General Electric in November to discuss how the company's expertise could meet Devon's needs. One presentation focused on GE's natural gas power generation, which had been used successfully in the gas-rich Marcellus Shale.
Matlock said GE had a unit installed and running within four months of that meeting after learning of Devon's technical requirements.
He said the natural gas fueled generator provides enough power for all of the equipment at the site southwest of Stillwater. It uses about 200 cubic feet of gas a day directly from the wellbore.
Matlock said the pilot project went so well that Devon has committed to lease additional units from GE.
Devon also is working with GE to make the generators more portable so they can be moved between sites easily, if necessary.
Matlock said gas-powered generators are more expensive than diesel ones, but Devon is able to offset that expense with its fuel savings.
He said Devon expects to use natural gas generators at existing Mississippian wells and new ones when power from the electric grid is not available.
Devon is ramping up its activity in the Mississippian, with plans to spend $1.2 billion this year to drill about 400 wells.
CONTRIBUTING: Adam Wilmoth, Energy Editor