Spurred by the need for natural gas, geological engineers are debating a hydraulic fracking technique that pollutes vast amounts of water when freeing natural gas from rocks.
“Oil and natural gas occur in sedimentary rocks that have pores in them,” said Mark Stewart, a professor of hydrogeology at the University of South Florida. “In some rocks, the pores have low permeability, which means the pores are small and restricted. Hydraulic fracturing creates larger pore space so gas can travel to wells.”
According to the Safe Water Drinking Foundation, current hydraulic fracturing techniques use millions of liters of water that can lower groundwater levels and reduce pressure levels in nearby aquifers. This can allow methane gas to create gas bubbles that seep into shallow bodies of water or household pipes, which can be dangerous and poisonous to people.
Because natural gas can be a scarce commodity that has damaging environmental factors, other ways of obtaining it were pioneered in Canada for use in states such as Pennsylvania. The company GasFrac wants to use propane gas instead of hydraulic fracturing, which uses water, said Stewart.
Nowadays, natural gas and oil reserves are developed in very low permeability sediments, which would not have been done before when oil and gas was readily available. Stewart said, when creating these reserves, billions of gallons of water are used and injected into the rocks to break them up at high pressure, which leaves polluted water on the ground surface during the process.
Helen Delano, a geological engineer at the Pennsylvania Geological Survey, said in a phone interview on November 15 that water used in hydraulic fracturing damages the environment because it contains salts, chemicals and other environmentally damaging wastes.
“That’s where the debate over fracking comes from in our state,” Delano said. ”Is it worth the risk? As I said, it’s still being debated.”
Stewart said hydraulic fracturing would only yield a small economic benefit.
“At the moment it is just barely worth it for companies to do hydraulic fracturing to increase the yield of a well,” Stewart said. ”The cost of natural gas is low and the cost of hydraulic fracturing is high.”
In January 2011, GasFrac published a flowback guide saying the reusable HD5 propane they use will turn into a vapor that will return to the ground surface for collection.
Jack Hutchings, a geology master’s student at USF, said using gas could allow natural resources to be recycled and reduce the cost to consumers.
“Using water currently is a high cost to the industry to dispose of the contaminated water. Since most drilling companies are exempted from taking adequate safeguards due to laws passed in 2004, they don’t do it,” said Stewart.
The Environmental Protection Agency announced in June 2011 that it would conduct case studies in five states for evidence of water contamination from June 2011 through 2012.
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