OU researchers strive to repurpose retired oil wells for geothermal energy to heat buildings

A team of researchers from OU’s Mewbourne School of Petroleum and Geological Engineering are working to turn abandoned oil and gas wells into geothermal wells that will later heat two schools in Tuttle.

Led by OU petroleum and geological engineering associate professor Saeed Salehi, researchers will tap into geothermal hotspots containing water below the Earth’s surface to utilize geothermal energy gathered by natural heat, according to a university press release. The project will pipe hot water in the Earth to heat buildings.

“Researchers from around the world are doing simulations (and) calculations to show that this concept may work, but this is the first time somebody is going to go and do it,” Salehi said in the release. 

The project is expected to last three years. During this time, the team will determine the viability of four retired oil wells for geothermal production. The wells range from 10,000 to 11,000 feet deep. 

“We are blessed with so many of these wells throughout the state. They are close (to) the schools, close to factories, close to farms. In Oklahoma, we do not need to invest in miles of pipelines to deliver energy,” Salehi said in the release.  

The wells will first be modified to produce geothermal energy. Then, researchers will spend a year measuring the energy production to determine if the output aligns with their estimates and if the wells will be capable of creating enough energy to heat the two schools, according to the release. 

The project will partner with Runar Nygaard, the director of the Mewbourne School of Petroleum and Geological Engineering, and the National Renewable Energy Laboratory. Donations by Blue Cedar Energy and energy technology company Baker Hughes put the project value to almost $3 million.

OU’s Mewbourne College of Earth and Energy offers both petroleum engineering and geology programs. Salehi said in the release that the project is the “perfect integration” of these disciplines. 

“At the University of Oklahoma, we pride ourselves on the pursuit of energy solutions that are both reliable and environmentally sustainable,” Mewbourne College of Earth and Energy Dean J. Mike Stice said in the release. “Geothermal energy is a prime example of a zero-carbon technology that complements our other areas of energy expertise. Dr. Salehi’s project will provide a real-world application of the technology that can be leveraged within the state and nation, as a whole.”

Salehi said in the release that geothermal drilling in the U.S. isn’t “up to scale” due to beliefs that western states and Hawaii have more potential for geothermal energy and the financial risk associated with drilling geothermal wells. Salehi believes that Oklahoma could become the nation’s capital of geothermal energy.  

Many of the costs, risks and environmental impacts of drilling geothermal wells are eliminated when retired fossil fuel assets are used, according to the release.

“The largest geothermal operations are currently in California and Nevada,” Salehi said in the release. “In those regions, geothermal wells generally only need to be half the depth as wells in Oklahoma. However, they are drilled through solid rock, making it a longer, riskier, and more expensive process. In Oklahoma, though the wells are deeper, they are drilled through sedimentary basins — softer rocks.”

According to the release, Oklahoma’s history in the oil and gas industry enables the possibility for geothermal wells.  

“We have decades of experience drilling Oklahoma’s sedimentary basins and can drill an 11,000-foot well in a week. That cannot be done in other places, even at shallower depths,” Salehi said in the release.

Salehi and his team hope to apply for grants and state matching funds so other phases of the project can become possible, which include heating the schools. If the next phase of the project occurs, the Tuttle schools will be the first buildings in the world heated by geothermal energy from repurposed deep oil wells.