Letting off steam: new research through OU could lead to increased energy production, reduced costs
NORMAN — While the U.S. is one of the world’s top geothermal energy resources, the technology remains largely untapped across many areas of the country.
Geothermal wells operate in tandem with injection wells to produce steam created by water injected into hot underground formations of rock. The steam is brought to the surface and used to power turbines, generating electrical power.
A petroleum engineering professor at the University of Oklahoma believes there may be a way to capture more steam, and therefore more energy.
Ahmad Ghassemi, the McCasland Chair at the Mewbourne College of Earth and Energy, will examine whether additional sub-surface fractures could increase the amount of steam produced. He recently received $2.5 million from the U.S. Department of Energy to do the work, university officials said, and an additional $700,000 from Coso Operating Co.
Traditional and 3D-modeling technology will be used to analyze a previously drilled geothermal production well on the grounds of the Naval Air Weapons Station at China Lake and the geology it taps.
The well is one of hundreds that tap geothermal energy in the Coso Volcanic Field in eastern California, Ghassemi said.
The team's goal is to develop plans to create new sub-surface fractures that could increase the amount of steam produced. The process they intend to use to create additional fractures will be similar to the one oil and gas producers use to complete horizontal wells, except in this case, the temperatures involved are much higher.
Because of the heat, the team will be testing whether mechanical packers could be successfully used to isolate certain portions of the well for stimulation, Ghassemi said. The team will model different scenarios where the well is stimulated using high-pressure, low-pressure and cycled injection operations.
“We will try to anticipate how the rock might behave using different injection scenarios,” he said.
Once the plan is developed, they will stimulate the well and then monitor the reworked well over time to track its performance.
Ghassemi anticipates the project will take three years, noting his team includes researchers from the U.S. Navy Geothermal Program Office, Steve Pye of the University College London and industry experts from Coso Operating Co., Veizades & Associates, and GeoLogica.
The team has expertise with geothermal energy, geological field work, state-of-the-art 3D modeling, experimental capabilities, drilling and wellbore construction experience, oil and gas experience, and specific knowledge of the regional geology of the Coso Volcanic Field, Ghassemi said.
Graduate students from OU’s Mewbourne College of Earth and Energy also will be involved.
“Involvement of postdoctoral and graduate students from OU gives the project a nice educational aspect as well,” said Ghassemi. “Not only will it contribute to their education, but it can potentially expand the geothermal workforce that is needed as the technology expands in the country.”
News of the grant’s award was applauded by both U.S. Rep. Tom Cole, R-Moore, and university officials who predict the research could unlock ways to reduce costs for future fields.