CCS Wells Technology Roadmap

CCS plays a key role in the UK reaching its Net Zero target by 2050.  Ensuring the long-term containment of CO₂ is essential for the CCS industry’s success, with wells serving as a vital element in both the storage operation and the integrity and monitoring of storage sites.

The UK North Sea offers substantial storage potential and there are currently twenty-seven CO₂ appraisal and storage licences on the UK Continental Shelf (UKCS). With its long and successful history in well lifecycle operations offshore within the oil and gas industry, the UK is well positioned to transfer tools, technologies and expertise from the oil and gas industry to the emerging CCS industry, however it must be recognised that CCS wells present their own unique challenges.

This CCS Wells Technology Roadmap, developed by the Net Zero Technology Centre (NZTC) and DNV for the North Sea Transition Authority (NSTA), serves as an industry resource to raise awareness of deployable technologies capable of addressing the challenges posed by CCS wells.  Additionally, technology gaps and challenges not yet addressed are detailed, with emerging solutions and areas for future technological advancement highlighted.

Materials and equipment

CCS wells require carefully selected materials and equipment to withstand challenging conditions, such as corrosion, thermal and pressure cycling, rapid phase changes and extreme cold, which may be experienced over the life of the well and post-operation abandonment.  Advanced materials including corrosion-resistant alloys and specialised cements are available and work is ongoing to validate and qualify equipment, much of which is transferred from the oil and gas industry, for use in the CO₂-rich environment within which CCS wells will need to operate.  Industry collaboration, such as through joint industry projects, is helping drive the standardisation and qualification of materials and equipment.

Intervention and workovers

Intervening and performing workovers on CCS wells face the challenge of the presence of CO₂ or CO₂-enriched fluids in the well.  Again, while much of the equipment used is similar to conventional oil and gas operations, additional validation and risk management is necessary to ensure safe and effective well maintenance, with industry experience in this area still developing.  Well control and CO₂ handling for CCS wells is particularly important and an area where potential gaps exist, however technological solutions are emerging in this space.

Monitoring

Regarding monitoring, a variety of advanced technologies are commercially available and emerging to support robust well monitoring for CCS projects, ensuring that CO₂ remains securely stored and regulatory obligations are met. These include high-resolution sensors and gauges, fibre-optic systems, wireless telemetry, and tracer technologies for real-time detection of leaks, verification of well integrity, and to monitor CO₂ injection and track plume movement. The main challenge is achieving an optimal balance between comprehensive monitoring and cost-effectiveness, supporting safe and long-term storage in alignment with the economic realities of CCS operations.

Remediation of legacy oil and gas wells

In addition to the aforementioned topic areas related to CCS wells, legacy oil and gas wells, if located within a CCS storage complex or in pressure communication, have the potential to act as leak pathways and therefore pose a significant threat to the secure storage of CO₂ if their integrity is compromised or they have not been abandoned to appropriate standards.   For this reason, remediation technologies for legacy oil and gas wells has also been addressed within this roadmap, with a specific focus on well re-entry.

Many technologies required for CCS well activities already exist within the oil and gas industry but require adaptation and validation to ensure suitability.  As the CCS industry develops and data availability increases the industry will be able to advance its understanding of CO₂ behaviour and operational envelopes assisting in advising adaptation requirements and standardisation opportunities.  Standardisation in the well basis of design, testing procedures and qualification protocols have the potential to reduce costs which, in an industry with a challenging economic landscape, is vital. It should also be noted that, due to the infancy of the CCS industry, unforeseen challenges are likely to be encountered which will require future technological advancements. The CCS industry, with transferrable technologies and expertise from the oil and gas industry, will be well placed to deliver these.