NSTA explores monitoring offshore carbon storage sites


Featured image: Seismic MMV summary, courtesy of NSTA

Monitoring, measurement and verification (MMV) activities must be tailored to clearly identified carbon storage site risks and uncertainties, a report has concluded.

On 1 August, the North Sea Transition Authority (NSTA) published a report, exploring the role of monitoring for offshore carbon storage sites, placing a particular focus on those sites with restricted access because of co-location with other marine industries, such as offshore windfarms. It found there are no one-size-fits-all solutions, explaining that MMV activities for carbon storage sites must consider aspects such as store type, geometric arrangements and scenarios, injection strategies, met-ocean and seabed conditions.

Seismic surveying activities for carbon storage sites in and around offshore windfarms were noted as being extremely challenging. This is particularly the case when conventional long-cable towed seismic streamers are deployed. There are potential mitigating solutions, however, albeit with higher costs and more limited coverage.

It further stressed that monitoring, measurement and verification strategies and tools for carbon storage sites need to address conformance irregularities and containment breaches. This should use a risk-based approach, with a robust suite of surface, marine and downhole tools and methods needing to be tested and deployed to support these strategies.

There is an expectation that first-of-a-kind projects may potentially be over-engineered, as industry test and certify different monitoring, measurement and verification methods. This will be crucial to maintaining public confidence, with each project requiring a robust environmental baseline.

Periodic access to carbon storage infrastructure within offshore windfarms was identified as a significant obstacle. It explained that based on current technologies, large physical overlaps between carbon storage sites and windfarms are, at present, not considered to be feasible with respect to infrastructure and resulting requirements for routine and emergency operational access requirements.  

It concluded that the co-existence of carbon storage and offshore windfarms calls for early and active collaboration, involving cross-disciplinary teams of specialists to optimise the co-location seabed access design on a project-by-project basis. These teams, it added, should be established early. This approach should also seek to explore the synergies between projects for both data-gathering and operations.