Researchers have created geochemical tracers that can identify hydraulic fracturing flowback fluids in the environment.
The innovation could help researchers determine where frac fluid has been released or spilled, in hopes of improving how shale gas wastewater is treated and disposed of, the National Science Foundation reported.
"By characterizing the isotopic and geochemical fingerprints of enriched boron and lithium in flowback water from hydraulic fracturing, we can now track the presence of 'frac' fluids in the environment and distinguish them from wastewater coming from other sources, including conventional oil and gas wells," said Duke University geochemist Avner Vengosh, who co-led the research.
The exploitation of unconventional oil and gas reservoirs through the use of hydraulic fracturing has been on the rise, and this new testing method could help assess the impact it has on our environment.
"This work is critical as it demonstrates that geochemical fingerprinting provides a powerful tool to differentiate potential sources of contamination and therefore guide efforts to mitigate environmental impacts," said Alex Isern, section head in NSF's Division of Earth Sciences, which funded the research.
Fracking liquids generally contain water, proprietary chemicals and sand; drillers inject these liquids into gas wells at high pressures in order to crack open shale and collect the natural gas stored within. Once the shale is cracked open, this fluid flows back to the surface along with the natural gas.
"The flowback fluid that returns to the surface becomes a waste that needs to be managed," Vengosh said. "Deep-well injection is the preferable disposal method, but injecting large volumes of wastewater into deep wells can cause earthquakes in sensitive areas and is not geologically available in some states."
The new technique could benefit industry, federal and state agencies that work to protect the environment.
The findings were published October 20 in the journal Environmental Science & Technology.
