Our research aims to understand the leakage risks in CO2 injection wells to make sure that underground carbon storage remains a safe and effective way to fight climate change.
Our investigation is about the damage that can happen to the cement sheath around a CO2 well, including how it cracks and separates from the steel casing and surrounding rock.
This damage may happen without leading to significant upward migration of CO2, for example when the cracking or debonding remains small and localised.
This is why our project will address not just the likelihood of damage occurring but also its evolution, potential mitigation using novel cements, and what this means for the overall risk of CO2 storage.
A key benefit of our project is that our findings will be used in our partner Quintessa’s carbon capture and storage operations in geological store siting, subsurface risk assessment, and selection of seals during well decommissioning.
Our research will provide new data on well damage that will improve Quintessa’s TESLA decision support software. As a result, the planned research will support effective decision-making as the UK carbon capture and storage sector continues to grow.
We believe our findings will help better understand practical limits on CO2 injection, such as injection rates and any requirement for heating before injection, especially following liquefied CO2 shipping as is being considered by some of the UK’s industrial clusters, including our project partner The Solent Cluster.
While our simulations will focus on UK conditions, our results will also be useful for other countries involved in geological CO2 storage.
Our partner, the Net Zero Technology Centre, is also involved in the ACT3 project RETURN and will help share our findings with operators and regulators in the UK, alongside our engagement in international conferences, workshops, and policy events.
Background
Deep geological storage of captured CO2 in the UK Continental Shelf saline aquifers and depleted oil and gas reservoirs is seen as a large-capacity long-term solution for emissions mitigation towards Net Zero 2050.
To keep geological storage effective, we must fully understand the risks of potential leakage. Any leakage could harm the environment and human health or reduce the benefits of mitigating climate change if CO2 escapes into the atmosphere.
In response to this, our proposal focuses on the leakage risk associated with the injection wells themselves, which are used to store CO2 in the ground. These wells, whether newly built or repurposed from oil and gas operations, can have defects that could develop into leakage risks during and after CO2 injection.
A review of UK North Sea oil and gas wells found that about one-third of wells had single barrier failures in the cement or steel parts, suggesting that such failures will be a key concern as CO2 storage expands.
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