Prabhakaran Manogharan (left), doctoral candidate in engineering science and mechanics, and Clay Wood (right), doctoral candidate in geosciences, run a series of tests on fractured rock using acoustic vibrations that simulate seismic activity. Manogharan is pictured using a multi-channel ultrasonic data acquisition system to adjust the test parameters and monitor the sample response — in the form of recorded ultrasonic signals — under load. Wood is controlling a bi-axial loading machine and applying the load according to a prescribed protocol to simulate rock in-situ condition. IMAGE: PROVIDED BY PARISA SHOKOUHI
Researchers awarded grant to advance geothermal energy science
6/7/2021
By Tessa M. Pick
UNIVERSITY PARK, Pa. — Over the last decade, geothermal energy has progressed throughout the world as an environmentally friendly, sustainable source of energy. Using the heat from the Earth’s crust, geothermal power plants harvest and store energy in massive underground reservoirs carved out of stone. Once built, the reservoirs are inaccessible and monitored remotely — but not infallible. Earthquakes and more can fracture the subsurface rock, risking the integrity of the reservoir and endangering energy production.
Parisa Shokouhi, associate professor of engineering science and mechanics and of acoustics at Penn State, is working to predict possible breaks and how to mitigate the potential fallout. Her team began its work in 2017 with a grant from the U.S. Department of Energy’s Basic Energy Sciences program. Now, the program has renewed the grant for a total funding amount of nearly $1.2 million.
“There is a growing need to understand how seismic and hydraulic characteristics of fractured rock can be used to illuminate the key mechanisms controlling subsurface flow, energy production and waste disposal,” Shokouhi said.
In the lab, the research team uses acoustic vibrations on fractured rock to simulate seismic activity. The team then studies the frictional, hydraulic and ultrasonic responses to create a model or image of the fractures. This model allows the team to predict how fluid will flow through the rock, even if the rock is underground and inaccessible.
By using seismic waves to predict the rock fracture properties, Shokouhi said she hopes to better understand how fluid flows through fractured rock to create more efficient methods of monitoring geothermal energy production.
“In geothermal energy, you need to know the permeability of Earth’s subsurface, and currently there is no way to do that,” Shokouhi said. “The same goes for storage of carbon dioxide and wastewater. Currently, there is no way of measuring the storage capacity. We have found that when you can monitor the seismic response of the subsurface from the ground level, you can infer the permeability of the ground, which tells us how much water you can inject and what the storage capacity is.”
Shokouhi’s research team on this project includes Jacques Rivière, assistant professor of engineering science and mechanics and of acoustics; Derek Elsworth, distinguished professor of energy and mineral engineering and of geosciences; Chris Marone, professor of geosciences; Jiang Jin, Shokouhi’s former doctoral student; Prabhakaran Manogharan, doctoral candidate in engineering science and mechanics; Clay Wood, doctoral candidate in geosciences; and Prabhav Borate, doctoral student in engineering science and mechanics.
“The collaborative opportunities at Penn State are what made this research possible,” Shokouhi said. “There are people on this team who are internationally recognized in their own field and when we put the team together, we became a really strong force. To be able to find researchers who have complementary expertise has been so helpful.”
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Parisa Shokouhi, associate professor of engineering science and mechanics and of acoustics at Penn State, recently received a grant renewal from the U.S. Department of Energy Basic Energy Sciences program for her team’s work in geothermal energy. IMAGE: PENN STATE
