As Norway and other nations intensify efforts to store carbon dioxide (CO2) in undersea geological formations, groundbreaking research from the Norwegian University of Science and Technology (NTNU) is shedding light on crucial questions about this process. With the world’s longest-running undersea CO2 storage project located at the Sleipner gas field in the North Sea, Norway is at the forefront of this environmental initiative.
Martin Landrø, an NTNU geophysicist and director of the university’s Centre for Geophysical Forecasting (CGF), encapsulates the core inquiries driving the research: “Where has my CO2 gone? Is it leaking or not?” These questions are fundamental as nations seek to mitigate climate change impacts by securely storing CO2 emissions.
Revolutionizing CO2 Visualization
The Sleipner project has injected a staggering 20 million tons of CO2 into a saline aquifer known as the Utsira Formation. To enhance understanding of CO2 storage dynamics, CGF researchers have employed an advanced data-analysis method called full-waveform inversion. This technique, utilizing seismic imaging, allows scientists to visualize the CO2 distribution with unprecedented clarity.
Ricardo Jose Martinez Guzman, a recent CGF PhD, has demonstrated the efficacy of this method in a new study. “Maybe 10 years ago, the full-waveform inversion from Sleipner was like wearing very foggy glasses,” said Philip Ringrose, a professor in Energy Transition Geoscience at CGF. “But this has now advanced so far that we can see all the layers and all these feeders.”
Innovative Monitoring Techniques
Currently, companies monitor undersea CO2 storage by towing acoustic sensors over formations in a grid pattern, akin to mowing a lawn. While effective, this method is time-consuming and costly. On land, drilling wells can provide direct data, but this is impractical for deep-sea sites like those in Norway.
Ringrose emphasizes the push towards geophysical data, “Here we don’t use wells to check where the CO2 is. We only use geophysical data.” This approach is not only due to the offshore location but also part of an effort to demonstrate the comprehensive capabilities of geophysical technology.
Laboratory Innovations and Future Prospects
To further refine CO2 monitoring, CGF researchers have constructed a new laboratory featuring a 2-by-4 meter tank filled with water and a large-scale model of the Utsira Formation’s cap rock. This setup serves as a testing ground for various measurement techniques.
Kasper Hunnestad, a CGF postdoc, oversees the lab. By manipulating the model and using ultrasonic sensors, he can simulate CO2 distribution and test the robustness of monitoring strategies. “What we can do is to challenge the system a bit,” Hunnestad explains. “We know what works. But what happens if you take away some of the data?”
The insights gained could significantly reduce monitoring costs and improve accuracy, making CO2 storage a more viable solution for carbon management.
Looking Ahead: Fiber Optic Solutions
As the demand for effective CO2 monitoring grows, CGF’s industrial partners are keenly interested in the lab’s findings. Ringrose notes the competitive nature of the field, with companies eager to offer precise CO2 tracking solutions.
Centre director Landrø envisions a future where fiber optic cables could revolutionize CO2 monitoring. These cables, already used for data transmission, could be deployed under the seabed to provide continuous monitoring. “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,” Landrø suggests.
The transition to fiber optics presents challenges, particularly in terms of cost and deployment speed, but the potential benefits are substantial. As research continues, Norway’s pioneering efforts in CO2 storage could set the standard for global carbon management strategies.
References: Ricardo Martinez, Vetle Vinje, Harrison Moore, Steve Hollingworth, Philip Ringrose, Alexey Stovas; Unraveling multi-layer CO2 plumes using the entire wavefield: Case study from the Sleipner storage site. Interpretation 2025; doi: https://doi.org/10.1190/int-2025-0016
