Well intervention for Carbon Capture and Storage – An Aquaterra Guide

Estimated read time: 9mins

Blog summary

Our Innovation Director, Ben Cannell, explores how Carbon Capture and Storage (CCS) is key to achieving net-zero targets and why well re-abandonment is crucial for its success. With CCS needing to capture 1 billion metric tons of CO₂ annually by 2030, finding safe, long-term storage solutions is essential. In this blog, Ben delves into how Aquaterra Energy’s Recoverable Abandonment Frame (RAF) addresses the challenges of re-entering and re-abandoning legacy wells, ensuring well integrity and secure offshore carbon storage for the future of CCS.

What is carbon capture and storage

Carbon Capture and Storage (CCS) is a technology designed to reduce the amount of carbon dioxide (CO₂) released into the atmosphere from industrial processes and power generation. It is seen as a crucial tool for achieving net-zero emissions targets, with climate models from the Intergovernmental Panel on Climate Change (IPCC) and the International Energy Agency finding it to be necessary for it to be capturing around 1 billion metric tons of carbon dioxide (CO2) by 2030 and several billions of tons by 2050 as part of their net zero scenarios.

Those enormous figures for captured CO₂ lead to one obvious question. Where are we going to put all of it? In this blog I will explore that question, demonstrating why storage in offshore geological formations holds the answer, tackling the technical challenges of how we do that, and deploying my own decades of offshore engineering experience as well as that of the Aquaterra Energy team.

Understanding How Carbon Capture Works

Before we get into the specifics of carbon storage, we need to start with the beginning of the puzzle, namely, capturing carbon. Carbon capture is the first step in CCS, where CO₂ is separated from other gases produced during industrial processes before it reaches the atmosphere. This is achieved using various methods like pre-combustion, where CO₂ is captured before the fuel is burned, or post-combustion, where CO₂ is removed after combustion.

Once the carbon is captured, the next critical step is transportation. This involves moving the captured CO₂ from its source to a suitable storage site. Pipelines are the most efficient and cost-effective option, especially for offshore or underground storage locations, though ships and trucks can also be used in some cases. Effective infrastructure is crucial to prevent leaks and ensure safe CO2 transport, making it a key component of the entire CCS chain.

It is after this stage that we return to the central question: what do we do with all that carbon once it’s been captured? This is where storage, the process in which CO₂ is safely stored underground, is essential to reducing emissions on a large scale.

The Role of Carbon Storage in the CCS Process

Carbon storage is a critical component of the CCS process, where captured CO₂ is safely contained to prevent it from being released back into the atmosphere. The success of CCS depends heavily on selecting appropriate storage sites and overcoming the technical challenges associated with long-term containment. Ideal storage sites are typically deep underground in geological formations, such as depleted oil and gas reservoirs or saline aquifers. These locations are well-suited for CO₂ storage due to their capacity and proven ability to hold fluids securely over long periods.

The good news is that global estimates suggest there is sufficient storage capacity to meet the world’s CCS needs for at least the next century. However, proper planning and management are essential. Geological CO₂ storage sites must be carefully selected, designed, and monitored to maintain their integrity and ensure that CO₂ remains safely stored for thousands, or even millions, of years.

Challenges of carbon storage using abandoned wells

Oil and gas fields are often ideal candidates for CO₂ storage due to their well-understood geological formations and existing infrastructure. However, one critical challenge in using these fields for CCS is the presence of legacy wells—abandoned or suspended wells that, if not properly sealed, can compromise the integrity of the storage site.

Legacy wells introduce vulnerabilities that heighten the risk of leakage, meaning that if they were previously improperly abandoned, it is essential to correctly re-enter and reseal them to ensure the success of the project. Traditional methods, such as relief well drilling, are often infeasible in shallow intersections or when the well’s azimuth and depth are unknown. Another approach is excavation. While possible, this requires removing large amounts of material and may still fail to effectively isolate the compromised well.

This led my team and I at Aquaterra Energy to develop a complete Our Recoverable Abandonment Frame (RAF) uses advanced seabed and subsurface surveying technologies to precisely locate wells, enabling secure re-abandonment through a vertical tieback method. This approach, combined with our broader expertise in well integrity assessments, seismic monitoring, and pressure-retaining barrier installation, ensures CCS projects are safe, efficient, and cost-effective.

The RAF not only protects well components from environmental stresses, such as wave-induced lateral and axial loading, but its modular design allows it to be reused across multiple wells, reducing costs by up to 80% and shortening project timelines by as much as 50%.

Monitoring stored carbon

Of course, once that CO₂ is tucked away, we need to make sure it stays there. Monitoring plays a vital role in confirming that the carbon remains securely contained within the geological formations, preventing any leakage that could undermine the environmental goals of the project. Continuous monitoring provides not only peace of mind but also a clear, trackable record of the CO₂’s behaviour underground over time.

At Aquaterra Energy, I played a key role in developing a specialised CO₂ monitoring platform that provides real-time data on storage site integrity, making it a key part of any CCS initiative. By using advanced technologies, the platform detects changes in subsurface pressure and potential leakages early, enabling quick responses. It seamlessly integrates with existing infrastructure, using sensors to track storage conditions, CO₂ plume movement, and detect anomalies. This continuous monitoring ensures the safety and effectiveness of carbon storage, helping meet regulatory requirements and keep stored CO₂ securely managed over the long term.

The Future of Carbon Capture and Storage

CCS is becoming a crucial technology for reducing global emissions, especially for industries where decarbonisation is particularly challenging. With over 40 large-scale projects already operational worldwide, CCS will play a key role in achieving climate goals. One of the most vital aspects of this process is ensuring the secure, long-term storage of CO₂. With the right infrastructure and technology, large-scale storage in offshore reservoirs can be a reliable solution for effective carbon containment.

At Aquaterra Energy, we bring decades of offshore engineering expertise to support CCS projects. Our services range from well abandonment assessments and offshore analysis, to equipment supply and full decommissioning, ensuring that storage sites meet safety standards and technical requirements for long-term carbon storage. For example, on INEOS’s pioneering Project Greensand, we are supporting with the life extension of an existing offshore platform for CO2 injection.

As the global focus on carbon reduction intensifies, having the right technical expertise will be critical to the success of CCS projects.  Get in touch with us to learn how our tailored solutions can help you meet your CCS goals efficiently and securely.

Key takeaways: 

In this piece we have answered:

Q: What is CCS?

A: CCS is a process that captures carbon dioxide (CO₂) from industrial emissions and power generation, preventing it from being released into the atmosphere. The CO₂ is then transported and stored in underground geological formations to help reduce global emissions.

Q: How does carbon capture and storage work?

A: CCS involves three main steps: capturing CO₂ from industrial processes, transporting it via pipelines or other means to a storage site, and securely storing it in deep geological formations, such as depleted oil and gas fields or saline aquifers, to prevent it from re-entering the atmosphere.

Q: Why are legacy wells a challenge for CCS projects?

A: Legacy wells, which are abandoned oil and gas wells, can pose risks if they’re not properly sealed. They may allow CO₂ to escape, which can compromise the effectiveness of a CCS project. These wells must be securely re-abandoned to ensure long-term CO₂ storage.

Q: What role does monitoring play in CCS?

A: Monitoring is essential for ensuring that stored CO₂ remains safely contained over time. It helps detect any changes in subsurface conditions or potential leaks, ensuring quick responses to maintain the security and environmental integrity of the storage site.

Q: How does CCS help achieve net-zero targets?

A: CCS is vital for reducing emissions from sectors like heavy industry and energy production, where it’s hard to cut CO₂ emissions. It’s seen as a key component in reaching global net-zero goals by capturing and safely storing large amounts of CO₂.

Q: Can all captured CO₂ be used for other purposes?

A: While a small portion of captured CO₂ can be repurposed into products like fuels or materials, demand for such uses is limited. For large-scale reduction in emissions, long-term underground storage is necessary to manage the volume of CO₂ captured globally.

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