Researchers and companies in the U.S. are investigating ways to store huge amounts of carbon dioxide underground. The greenhouse gas contributes to climate change by trapping heat in the atmosphere, prompting some to develop technology to capture it and inject it into the earth.
A new article analyzing cases of induced seismicity in Oklahoma, Kansas, Texas and New Mexico, published in the International Journal of Greenhouse Gas Control, said carbon storage is critical to limiting the effects of climate change.
“But if it's associated with induced seismicity, then I think it will really undermine public support for those activities,” said study author and Stanford University Professor Emeritus Mark Zoback.
The risk of triggering earthquakes by injecting carbon underground in certain geological formations has been known for decades, researchers say. Areas with hard and brittle rocks are more likely to be unsuitable for injection.
Zoback said he and co-author Peter Hennings, a research professor at the University of Texas, used wastewater injection as an analogy to explain what could happen with large-scale carbon storage. Captured carbon is converted into a supercritical fluid, which is similar to a liquid, for underground storage.
The paper analyzed some of Oklahoma’s series of earthquakes from the 2010s that were confirmed to be caused by oil and gas operations. Zoback said the affected area isn’t suitable for high amounts of carbon storage.
“ In north-central Oklahoma, one should not be doing large-scale carbon storage in the Arbuckle formation because we've done that experiment, we know what happens,” he said. “Now, that doesn't mean there aren't opportunities to store CO2, for example, in depleted oil and gas reservoirs.”
At least two companies have submitted applications to store carbon underground in Oklahoma as of late August. CapturePoint withdrew its bid to operate carbon wells in Osage County in January after the Environmental Protection Agency indicated it needed more information about the site’s geology and potential for seismicity, a spokesperson for the company said.
Another company, NexGen Carbon Solutions, applied this summer to operate 10 carbon wells in Osage County. In an announcement, it said it planned to store 72 million tons of carbon over 20 years in the wells. The EPA application is currently in a technical review.
To welcome carbon companies, the state legislature passed a bill laying out rules for local regulation of carbon storage wells, known as Class VI under the EPA. At the time of passage, the state planned to ask the federal government for primacy to oversee and regulate its commercial wells.
“This is probably the most important piece of legislation you'll see this year for future economic development in the state of Oklahoma,” bill co-author Rep. Ken Luttrell (R-Ponca City) said during a May 1 House floor session. “These companies are willing to come to Oklahoma and invest millions of dollars in our economy with these Class VI wells.”
Zoback and Hennings wrote that they want the research paper to serve as a guide for the public to understand the body of information on carbon storage and the risk of earthquakes. Zoback said public perception of underground carbon injection is key to putting away millions of tons of the greenhouse gas.
“ The biggest threat in many cases will not be the shaking of the ground, but will be undermining public confidence that it can go forward safely,” he said.
StateImpact Oklahoma is a partnership of Oklahoma’s public radio stations which relies on contributions from readers and listeners to fulfill its mission of public service to Oklahoma and beyond. Donate online.
