The results for the 2D field cross-section, illustrating the total distribution of the CO2 mass 500 years after the end of injection (time = 550 years). Credit: International Journal of Greenhouse Gas Control (2025). DOI: 10.1016/j.ijggc.2025.104519

The geological storage of carbon dioxide (CO2) in deep geological formations is considered internationally, as well as in Germany, to be one of the key technologies for achieving ambitious climate targets. But how can potential storage sites be reliably assessed? And how dependable are computer simulations that must predict the behavior of CO2 in the underground over decades or centuries?

A large-scale international research initiative—the 11th Society of Petroleum Engineers Comparative Solution Project (SPE11 Benchmark for short), has systematically examined how differently modern simulation tools predict CO2 storage processes. Forty-five research and industry groups worldwide registered to take part, including a research team from the Institute of Geosciences at Kiel University (CAU).

The new study, recently published in the International Journal of Greenhouse Gas Control, provides one of the most extensive model comparisons conducted in recent years for CO2 storage simulations. The project provides a comprehensive open database containing more than 400 GB of freely accessible model data, interactive visualizations, and newly developed methods for systematically comparing complex simulation results. The findings offer valuable guidance for policymakers, permitting authorities, and practitioners who assess future CO₂ storage projects.

New evaluation criteria for CO2 storage

In geological CO2 storage, the gas is injected into porous rock layers at great depths, where a range of physical and chemical processes can immobilize it over long periods. To predict the effectiveness of these storage mechanisms, specialists rely on computer-based, process-oriented models. For the first time, under the leadership from University of Bergen (Norway), 45 institutions from11 nations, including leading scientific organizations from the United States, Australia, Germany, France, China, Canada, Saudi Arabia, Netherlands and the U.K., have contributed their simulation results to a large coordinated study.

This collaboration has produced an unparalleled collection of comparative datasets, insights, and methodological advances. "The submitted datasets were analyzed in depth and their differences examined systematically. The outcome is a robust assessment of the numerical tools used to predict geological storage processes—an essential foundation for any safe and long-term CO2 storage," explains Professor Sebastian Bauer, head of the Geohydromodelling working group at the Institute of Geosciences at Kiel University.

CO2 storage—a special scientific challenge

The storage of carbon dioxide in deep geological formations poses particular challenges for numerical modeling due to the very long time scales involved, often spanning decades to centuries, as well as the spatial complexity of the subsurface. The SPE11 benchmark study provides a new scientific foundation for this task. It comprises three subtasks of increasing complexity: a two-dimensional laboratory experiment, a two-dimensional field cross-section, and a fully three-dimensional field model of a hypothetical storage formation.

Researchers at Kiel University were able to deliver results for all three tasks by making use of the university’s high-performance computational (HPC) resources. "The three-dimensional case in particular required demanding, non-isothermal multiphase simulations that could only be completed within acceptable computing times using the HPC facilities at Kiel University. This enables us here in Kiel to perform the necessary simulations for field applications as well" says Dr. Firdovsi Gasanzade, co-author of the study from the Geohydromodelling working group at the Institute of Geosciences.

"The study demonstrates the need for transparent standards, especially when the results must serve as a basis for political decision-making and permitting procedures," adds Professor Sebastian Bauer, whose working group is also involved in the German Marine Research Alliance (DAM) projects on carbon dioxide storage in and beneath the seabed (CDRmare).

The study is also highly topical in light of recent political developments. Germany has just adopted a new legal framework: since the end of November, CO2 storage (carbon capture and storage, CCS) in the seabed or in deep geological formations is now permitted in principle and represents an important policy instrument on the path toward achieving climate targets.

More information: Jan M. Nordbotten et al, Benchmarking CO₂ storage simulations: Results from the 11th Society of Petroleum Engineers Comparative Solution Project, International Journal of Greenhouse Gas Control (2025). DOI: 10.1016/j.ijggc.2025.104519

Citation: Safe CO₂ storage in the Earth only possible with robust modeling (2025, December 10) retrieved 10 December 2025 from https://phys.org/news/2025-12-safe-storage-earth-robust.html

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