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Stored Carbon Staying Put

A carbon capture and storage site off the coast of Tomakomai, Japan, has been keeping carbon dioxide out of the atmosphere by injecting it deep into the seafloor for storage.

But ever since injection began about three years ago, a big question has remained: Was the greenhouse gas trapped for good? Or could it quietly be leaking back into the atmosphere where it could contribute to climate change? Researchers from The University of Texas at Austin have answered that question, finding that the carbon dioxide is stored safely and securely.

Their work relied on a pioneering 3D seismic technology that renders the subterranean seafloor in fine detail.

“This is the first time that highresolution 3D seismic technology has been deployed over an active offshore injection site,” said Tip Meckel, a geologist at the Bureau of Economic Geology at the UT Jackson School of Geosciences. “Nobody has done that before. So that’s a big success in and of itself.”

The findings were published in print in the September issue of International Journal of Greenhouse Gas Control. The Tomakomai site in northern Japan is a large-scale test project that stores carbon from a nearby refinery under the seafloor. Scientists from the bureau’s Gulf Coast Carbon Center (GCCC) were brought into the project through a partnership with the U.S. Department of Energy.

The Tomakomai site already has monitoring systems in place, but none that can give a crisp picture of what is going on underground like the method used by Meckel. The P-cable system used by Meckel and other researchers at the GCCC can reveal geologic features, such as large faults that could leak from about a mile under the seabed to the surface.

This technology can also help scientists select sites that are best for future carbon capture projects by ensuring that the rock above the injection zone will act as a trap, keeping the fluids contained.

To Meckel’s knowledge, UT is the first and only university in North America to conduct research on P-cable technology.

The bureau acquired the $2.5 million system with help from a Department of Energy grant in 2012. Meckel tested the technology during several surveys off the shore of Texas before deploying it off the coast of Japan. The nearoffshore Gulf of Mexico is geologically similar to that at Tomakomai and has been a target for scientists who study the subsurface to find sites with high potential for safe carbon dioxide storage. The proximity of Texas’ oil and gas operations to the Gulf of Mexico also creates a great opportunity for carbon capture and storage.

“The Gulf of Mexico region is a hot spot for potential carbon management, with some of the nation’s leading researchers and infrastructure,” said Jerry Carr, study project manager at the National Energy Technology Laboratory of the U.S. Department of Energy. “By leveraging the bureau’s history of successful international collaboration with Japanese counterparts, and this technology now successfully demonstrated, the Department of Energy has more diagnostic tools available to support the potential of offshore carbon mitigation in
the U.S.”