Federal researchers are testing whether hydraulic fracturing fluids can travel thousands of feet via geologic faults into drinking water aquifers close to the surface, a US Department of Energy official said Friday.
A fault from the Marcellus Shale formation, which is thousands of feet below the surface, could provide "a quick pathway for fracking fluids to migrate upwards," said Richard Hammack, a spokesman for the US Department of Energy's National Energy Technology Laboratory.
The experiment is being carried out at a site in Greene County in southwestern Pennsylvania where conventional shallow wells were drilled and long since capped, NETL said on its website. Drillers are now actively drilling in the county in the Marcellus Shale formation.
The study will provide regulators, landowners and the general public "an unbiased, science-based source of information which can guide decisions about shale gas development," NETL said.
The study also will help the industry "develop better methods to monitor for undesired environmental changes" and develop technology or management practices to address the changes, NETL said.
Speaking at a congressional briefing in Washington, Hammack said faults "form a plane that allows fluids to move up through the frack." Some faults can be easily seen and avoided, but Hammack said some faults are not easily detected and could extend from the Marcellus Shale formation into other formations close to the surface.
The testing "is taking place right now," Hammack said. "It should be completed next week. Within a month, we will have the micro-seismic data that will show how high fracture fluids have migrated upwards" toward the surface.
He said that Pennsylvania has a long history of oil and natural gas production and thousands of wells were drilled before the state mandated drillers map their locations in 1921. There is a concern if these well bores penetrated faults they also could be a means for fracking fluids to travel to the surface, he said.
All of these "vulnerabilities" are present at the Greene County site where researchers can "examine and quantify" all of these factors, he said.
