As Norway and other nations intensify efforts to store carbon dioxide (CO2) in undersea geologic reservoirs, groundbreaking research from the Norwegian University of Science and Technology (NTNU) is shedding light on critical questions surrounding this method of carbon capture. The research aims to address concerns about the whereabouts and integrity of stored CO2.
Martin Landrø, a geophysicist at NTNU and director of the university’s Centre for Geophysical Forecasting (CGF), underscores the importance of understanding CO2 storage.
“Where has my CO2 gone? Is it leaking or not? Those are the basic questions actually,”
he states, highlighting the need for precise monitoring techniques.
The Pioneering Sleipner Project
Norway is home to the world’s longest-running undersea CO2 storage project at the Sleipner gas field in the North Sea. Since its inception, the project has injected 20 million tons of CO2 into the Utsira Formation, a saline aquifer. This initiative has become a model for carbon storage efforts globally.
Researchers at CGF have employed a sophisticated data-analysis technique known as full-waveform inversion to enhance the accuracy of CO2 monitoring at Sleipner. This technique, which utilizes seismic imaging, has significantly improved the visualization of CO2 distribution within the reservoir.
Ricardo Jose Martinez Guzman, a recent PhD graduate from CGF, has published a paper demonstrating the efficacy of this method. Philip Ringrose, a professor in Energy Transition Geoscience at CGF, compares the advancement to a revolution in understanding CO2 storage.
“Maybe 10 years ago, the full-waveform inversion from Sleipner was like wearing very foggy glasses. But this has now advanced so far that we can see all the layers and all these feeders,”
he explains.
Innovative Monitoring Techniques
Current monitoring techniques involve using ships equipped with acoustic sensors to survey the storage formations. However, this method is time-consuming and costly. In land-based storage areas, companies can drill wells to monitor CO2, but this is not feasible in offshore sites like Sleipner, where storage formations lie deep beneath the seabed.
Ringrose notes,
“Here we don’t use wells to check where the CO2 is. We only use geophysical data. That’s partly because we’re offshore, but it’s also because we’re pushing the technology to show you can see everything with geophysics.”
Laboratory Innovations
In addition to advancing analytical tools, CGF researchers have constructed a new laboratory to simulate and study undersea storage conditions. The lab features a large tank filled with water and a mockup of the Utsira Formation’s cap rock, which is crucial in preventing CO2 leakage.
Kasper Hunnestad, a CGF postdoc, manages the lab and conducts experiments to test various monitoring techniques. By manipulating the amount of air—used as a CO2 proxy—injected into the system, he can study the distribution of CO2 over time.
Hunnestad explains,
“What we can do is to challenge the system a bit. We know what works. But what happens if you take away some of the data? What if you don’t have the luxury of having all the data, can we still see how the CO2 is distributed?”
These experiments could lead to more cost-effective and accurate monitoring methods.
The Future of CO2 Monitoring
CGF’s industrial partners are keenly interested in the lab’s findings, seeing significant business opportunities in the field of CO2 monitoring.
“The competing geophysical companies who are our partners want to be in this space because they see a business opportunity,”
Ringrose notes.
Looking ahead, Landrø envisions using fiber optic cables for CO2 monitoring. These cables, already used for data transmission, have shown promise in other CGF research, such as tracking whales offshore of Svalbard.
“What we foresee in the future is that if you have a storage area like this, you deploy not conventional seismic cables, but fiber optic cables and you just plough them 10 or 20 centimeters below the seabed,”
he suggests, highlighting the potential for innovation in this space.
As the world grapples with climate change, advancements in CO2 storage and monitoring are crucial. Norway’s efforts at Sleipner and NTNU’s research are paving the way for more effective carbon capture strategies, with the potential to significantly impact global carbon management efforts.
