“We expect that such work will introduce novel ways for studying the procedures that occur during hydraulic fracturing in a more regulated lab setting,” says Travis Tasker, a doctoral candidate in environmental engineering at the Penn State. “It could also have implications for balancing the wastewater that returns to the surface or comprehending down-hole mineral alterations that could create clog pores, precipitate and diminish a well’s gas productivity.”
Numerous gas formations, like the Marcellus shale, exist multiple thousand feet below the layer in higher temperature and pressure environments. Hydraulic structuring also called as fracking is a popular method for extracting natural gas from such formations.
Fracking uses the procedure of injecting millions of gallons of a mixture prepared of sand, chemical and water additives into shale formations at increased pressures.
Such injection results the shale to fracture and release trapped gases. After the fracturing happens, the chemical additives, along with the metals linked with the shale itself, revert back to the surface in wastewaters at big concentrations.
Since many of the chemicals utilized for natural gas extraction has chronic or acute health effects in humans, degradation, transformation and the transport of such additives is vital to comprehend when considering the management and disposal of the wastewater that returns back to the surface.
“The ultimate goal of our project was to comprehend how the additives in hydraulic fracturing fluids affect the metal mobilization from shale and how they may be altered or degraded after being subject to the high temperatures and pressures during hydraulic fracturing,” says Tasker.
To answer such questions, the group that included Tasker, William Burgos, lecturer of environmental engineering, Paulina Piotrowski, a doctoral student in biogeochemistry and chemistry and Frank Dorman, an associate lecturer of molecular biology and biochemistry had to determine where the metals were concentrated in the shale samples and how the composition of hydraulic fracturing fluids are altered under high pressure and temperature conditions.
To analyse where metals were concentrated, the group gathered deep shale samples from depths bigger than 4,000 feet from six locations throughout Pennsylvania and disclosed them to a range of distinct solutions designed to displace the metals from particular minerals within the shale.
Next they revealed the shale samples to high pressures and temperature conditions with a synthetic hydraulic fracturing fluid representative of what numerous gas companies utilize in this field. The eventual fluid was then examined to determine how particular conditions like pressure, temperature, organic and pH compositions affected the rate of fracturing fluid additives and metal movement from the shale and to analyse exactly where in the procedure the metals were being mobilized.
This research also disclosed that numerous additives utilized in the synthetic fracturing fluids diminished the high pressure and temperature conditions or absorbed to the shale itself. But, surfactants a popular additive in numerous household detergents, reduced just minimally under all the tested pressure, shale, pH and temperature conditions
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