UKCCSRC Spring 2025 Conference – Parallel 2b – CO2 Storage (ECR Meeting Fund)

Zongqiang Ren (Cardiff University), Yao Fu (Cardiff University) and Chigbo Waliezi (University of Manchester) share their takeaways from the “Parallel 2b – CO2 Storage” session at the UKCCSRC Spring 2025 Conference.

At the recent UKCCSRC conference, the session titled CO₂ Storage provided insightful discussions on this topic. Featuring talks by Yihuai Zhang (University of Glasgow), Kate Dobson (University of Strathclyde) and Aaron Cahill (Heriot-Watt University), chaired by Stuart Haszeldine (UKCCSRC & University of Edinburgh), the session provided the latest advancements in CO₂ storage technologies, images facilities and strategies.

Yihuai Zhang started the session presenting on ‘The dynamic effect in CO₂ storage’. Understanding the pore-network model (PNM) of swelling effects and fracture permeability in CO2-shale interactions, the temporal dynamics of reactive CO2 and trapping in carbonated rock, and non-linear Darcy flow in CO₂-brine dynamics are crucial for advancing technologies in carbon storage.

Key points:

1. The swelling is dominant over all gas injection pressures in lower confining pressure.
2. The aperture size distributions considering stress change are more heterogeneous, and the average reduction in aperture size in low-density fractured samples is approximately double that of high-density fractured samples.
3. Channeling effects and resulting pore-structure changes significantly influence permeability and capillary trapping dynamics.
4. PNM simulation showed that the capillary pressure and trapping efficiency have a complex interplay between dissolution, fluid dynamics, and pore network topology, and the CO₂ residual trapping capacity could largely decrease after formation damage.

Kate Dobson started the session with the topic of ‘Image-based solutions for CCS storage challenges’.

Understanding the multi-scale experimental approaches and their role in predicting and controlling real-world behaviour is crucial for advancing carbon capture and storage (CCS) technologies. Her research highlights the importance of non-destructive imaging techniques to study multiphase flow, fracture propagation and material evolution in subsurface environments.

Key points:

1. Multi-scale experimental techniques provide insights across spatial (nm to km) and temporal (µs to millions of years) scales, bridging the gap between laboratory tests and real-world CCS storage conditions.
2. Material behavior in CCS systems involves complex interactions, including fracture mechanics, strain localization, precipitation and dissolution processes, which impact long-term CO₂ storage stability.
3. Ductile vs. brittle deformation mechanisms influence permeability and fluid migration, affecting storage efficiency and potential leakage risks.
4. Empirical validation through imaging is essential for improving simulation and predictive models, enabling better assessment of storage site integrity and long-term performance.
5. Multi-phase flow processes within fractured rock and porous media play a critical role in determining CO₂ trapping efficiency and capillary sealing behaviour.

Aaron Cahill started the session with the topic of ‘Legacy Wells and CCS: Managing Risks to Storage from Our Net Positive Past’. As carbon capture and storage (CCS) projects expand, understanding the impact of legacy wells on CO₂ storage security is crucial for long-term success.

Key points:

1. Legacy wells—Abandoned past oil and gas exploration wells pose potential leakage risks for CO₂ storage sites.
2. Effective monitoring and risk assessment strategies are essential to ensure the long-term integrity of CO₂ storage reservoirs.
3. Lessons from past energy activities can help develop best practices for securing CO₂ storage and mitigating potential risks.

Looking Ahead

While we look forward to exploring the potential contribution of legacy wells, integrating the application of image-based solutions, as highlighted in the works of Kate Dobson, takes us even a step further towards effective utilization. Furthermore, understanding the dynamic effect of CO₂ across a variety of reservoir types, including carbonate reservoirs, further supports the effective conversion of legacy wells and overall application of the CCS technology. Image-based solution tools can be deployed to address effective monitoring, risk assessment, and prediction through 4D imaging simulations.