The PilotSTRATEGY project is an ambitious five-year European R&D project, investigating subsurface geological sites for CO₂ storage in industrial regions of Southern and Eastern Europe to support the development of large-scale carbon capture and storage (CCS). The project is conducted by 16 governmental, academic and industry leaders from seven European countries, led by the French Geological Survey (BRGM), France’s national earth sciences institute.

The project team is focusing its research on deep saline aquifers, which promise a large capacity for storing CO₂ captured from clusters of industry sectors. Detailed studies are currently being carried out in three promising regions: the Paris Basin in France, the Lusitanian Basin in Portugal and the Ebro Basin in Spain. The project aims at assembling, acquiring and interpreting geological and geophysical data, assessing the saline aquifers’ storage capacity and integrity, developing concepts for proposed CO₂ pilot injection wells that will meet the best safety and performance standards, and engaging with the public to ensure societal acceptance.

Importance of 3D models

AspenTech is excited to support the PilotSTRATEGY project with its 3D geological modeling solution – Aspen SKUATM. 3D geologic models are crucial for estimating storage capacity, defining injection strategy, estimating the fate of CO₂ in the long-term, and providing a basis for risk analysis and phenomenological impacts. In that context, 3D geologic models, including the reservoir, caprock, underburden and overburden layers, had to be created for the three storage sites. The teams were looking for a geologic modeling solution that would allow them to integrate all available data, build a 3D model of the storage sites and integrate geological uncertainties into the static modeling process. They needed a product that would enable them to address the modeling challenges faced by the different teams and easily share results with other project members. Some of the organizations had seen good results using Aspen SKUA in the past, and based on those experiences, the members decided it would be a good solution for their requirements.

All three teams (France, Spain and Portugal) took a similar static modeling approach. They collected and analyzed all the available data, constructed a 3D grid of the storage site, propagated geological properties within the grid using advanced geostatistical modeling tools, and integrated uncertainties to evaluate their impact on storage volume and capacity.

Models maintain geological integrity and support informed decision-making

Despite taking similar modeling approaches, each team faced different challenges. The French team had access to extensive subsurface data for their selected storage site, while the Portuguese and Spanish teams faced limited data availability. The data types and formats to be integrated into the 3D model were very heterogeneous. In addition to wells and seismic data, some teams had to integrate gravimetric surveys, passive seismic, field analogues and photogrammetry.

The flexibility and advanced interoperability of Aspen SKUA enabled each team to integrate all available data seamlessly. Furthermore, the teams were able to adapt their property modeling workflows to the specificities of each storage site, whether they involved carbonate or clastic depositional environments, including channelized environments. In some cases, structural uncertainties were assessed to estimate variations in the gross rock volume of the storage formation.

Once the grid model was constructed, uncertainties in reservoir properties were also considered to evaluate their impact on porous volumes. As a result, the teams were able to generate a distribution of Net Porous Volume available. This knowledge helped confirm the suitability of the sites for storing CO2 and will support informed decision-making regarding the design and implementation of injection strategies.

The final step for all the teams in the static modeling process was to build a grid optimized for dynamic simulation of CO2 injection and storage. This phase involved upscaling geological properties to ensure the preservation of reservoir heterogeneities that could affect CO₂ flow dynamics over time. Aspen SKUA's ability to create fit-for-purpose grids and perform geologically consistent upscaling enabled geomodelers to deliver accurate models of the storage sites to the reservoir engineers. These models maintained the geological integrity needed to accurately predict the behavior of CO₂ flow.

In addition to the robust tools that AspenTech provides for CCS studies used in the construction of 3D geological models, Aspen SKUA also has a module that allows the integration of geological information collected from outcrops on fracture networks, and the stochastic modeling tools to evaluate the most relevant characteristics of these fractures. The work on this new module, conducted by the Portuguese team, was successfully carried out and tested in collaboration with AspenTech and will be integrated into the 3D reservoir model in future stages of dynamic simulation of the PilotSTRATEGY project.

Using Aspen SKUA, the PilotSTRATEGY teams were able to build 3D geological models for all selected storage sites, providing crucial information for estimating storage capacity and supplying the basis for risk analysis. The next step is to leverage the models to determine optimal well locations with maximum storage capacity and perform a comprehensive uncertainty analysis to address potential associated risks and to ensure the integrity of the CO₂ storage complex.

More information about the work performed by the PilotSTRATEGY teams to assess storage site capacity and integrity can be found on the project website: https://pilotstrategy.eu/about-the-project/work-packages/simulation.