Geoscientists help energy companies lessen their environmental impacts
Energy use in the United States is not measured in small numbers, it’s measured in BTUs, or British Thermal Units.
A BTU is the amount of energy used to raise the temperature of 1 pound of water 1 degree Fahrenheit. Those BTUs are measured in quads, as in quadrillions of BTUs.
A quadrillion looks like this: 1,000,000,000,000,000.
In the U.S. we use 100 quads of energy every year. Oil accounts for about 35 quads. Natural gas about 25; coal, 20; renewables, nine; and nuclear, eight.
So energy is important, and we need a lot of it. The challenge, says John Chermak, associate professor of practice in geosciences, isn’t finding the energy or even in extracting it, it’s doing so in the best possible way to minimize any potential environmental damage.
“There is a right way and a wrong way to get resources out of the ground, and our role as researchers and scientists is to help the extraction process by mitigating environmental impacts as much as possible,” he said.
An international expert
Chermak’s expertise with geochemical and hydrologic aspects of mining allow him to work with industry in 16 states and nine foreign nations. Currently, he spends a lot of time with companies involved in hydraulic fracturing, commonly known as fracking.
The process involves drilling vertically between a mile and 1.5 miles deep before drilling horizontally in a radius of about another 1.5 miles. The petroleum-containing rock at those depths is then fractured, and the gas, oil, and other recoverable assets are brought to the surface.
“Instead of drilling a vertical well and breaking rock to get gas or liquid or a mixture of both, fracking involves drilling vertically to depth and then horizontally, which is very expensive,” he said. “So using the same vertical shaft, the horizontal drilling can cover a large area with only one hole. Instead of half a dozen sites, there is only the one and it has allowed companies to go places to extract fossil fuels, petroleum, or wet gas far more effectively and profitably.”
Fracking requires more water than conventional drilling because water is used at high pressure as part of the horizontal drilling to fracture the source rock during fossil-fuel recovery. The water and the chemicals in the rock are at the heart of Chermak’s work.
“We get shale and other rock samples and test them to see what minerals and trace elements they contain,” he said. “Often there are concentrations of uranium, pyrite, arsenic, barium, salts, or other elements that require treatment or management so as not to cause environmental damage.”
Help for shale sites
Along with Madeline Schreiber, associate professor of hydrogeosciences, Chermak is looking at about nine shale sites in the U.S. and their mineralogy and trace element distributions.
“We help by providing companies with information on what the composition of the shales are so they can be prepared to properly treat and dispose of water and waste material when it gets to the surface,” Chermak said.
In addition to the elements in the rock being fractured, chemicals are added to the water used to fracture the rock. Steps have to be taken to capture the water and treat it properly when it comes back to the surface.
Some of the chemicals added to the water can be toxic and include organic solvents that prevent biological organisms from growing and getting in the way of permeability. Those ingredient mixtures are often treated as trade secrets by the drilling services and energy companies.
“My personal bias is that we’re better off treating the water and discharging it to a standard — but that’s more expensive,” Chermak said. “No matter what you do with treatment, there are still the organics and salts which need to be disposed of. It’s nothing along the lines of a spent nuclear fuel rod, but much of what we’re trying to protect through these measures is trout habitat, stream vitality, environmental health, and ground water supplies.”
From Chermak’s perspective, there is cheap, plentiful energy in the U.S. which has a lot of upside. Hydraulic fracturing is one method of extraction.
“If you compare it to coal mining, and many people don’t,” he said, “one can argue that hydraulic fracturing done well has a smaller environmental impact — and a temporary one at that. Fracturing has been going on for about 60 years, and the good news in this is that this method of recovery has allowed us access to natural gas, which we have a lot of in the United States. Natural gas for electricity production also means we use less coal which reduces our carbon dioxide emissions.
“In the end, doing it safely and protecting the environment starts with knowing what’s in the ground and how to mitigate it. That’s the problem we are trying to help solve.”
- For more information on this topic, contact Rosaire Bushey at 540-231-5035.
About the research
Associate Professor John Chermak talks about his work and why his team analyzes the trace elements in shale in this video.
Madeline Schreiber, associate professor of hydrogeosciences, talks about the complex relationship between groundwater and the aquifers they flow through in this video.
What's above ground offers clues to what's below ground
As fracking becomes more common, scientists at Virginia Tech are using research to make the search for energy more environmentally friendly, efficient, and economical.
Tom Burbey, an associate professor of hydrogeosciences in the College of Science, works through grants with the Department of Energy to study deformation, the small changes in elevation at the surface that can tell a lot about what’s going on deep in the earth.
When water or other fluids are taken from, or added to, the subsurface, it can stress the land system and result in the movement of the surface in either an up-and-down or sideways motion.
“The stresses are highly diagnostic and tell us a lot about what’s happening underground,” Burbey said. “We can characterize the nature of, for instance, an aquifer system, and determine how large it is, and where its boundaries are, by using information we can gather using highly sensitive surface-based instrumentation called strain meters, that measures deformation.”
Without these measuring devices, companies would need to drill dozens of wells to accurately gauge the makeup of the subsurface.