2nd International Workshop on Offshore Geologic CO₂ Storage

Publication Overview

This second workshop built on the conclusions and recommendations from the first workshop in 2016 by continuing the theme of ‘how to do’, and including sessions on how to find storage, monitoring developments, CO₂-EOR potential offshore, and infrastructure options, with presentations from Norway, the UK, the Netherlands, Australia, South Africa and Japan. New to all attendees were presentations on the US Department of Energy (DOE) -supported US projects looking at offshore storage in sedimentary basins in the Gulf of Mexico, the Atlantic and in basalts in the northern Pacific. Conclusions and recommendations were agreed, with a certain focus on infrastructure issues with the aim of engaging with operators of offshore infrastructure to make them aware of the opportunities from CCS and CO₂-EOR.

Publication Summary

Conclusions (separated into themes)

How to find storage:

• Site selection methods are becoming mature.
• Examples from different regions show some similarities as well as methods for adapting to regional geologic conditions, source distribution, and national goals and policies.
• Case studies at South Africa and Australia show methods of systematic refinement and down-selecting. 
• Lowering risk for projects includes favoring denser data about the subsurface, known injectivity, and proximity of sink to source. 
• A conservative approach favors assessing multiple sinks and multiple sources, so that one no-go does not derail the whole project.
• Use current best geologic practices – ie chronostratigraphic instead of lithostratigraphic to understand if target reservoir strata are continuous.
• Projects should not only be based on geological characteristics – the project needs to be large enough to be a business case.

Monitoring:

• A deep dive into monitoring plans shows that these plans are now successfully passing through negotiation with regulators. 
• Pragmatism in balancing risk reduction with cost management is illustrated in cases from Peterhead, ROAD, and Norway, although different monitoring approaches are still seen.
• AUV environmental monitoring reduces cost and reduces human safety issues.
• Multiple approaches to overburden and water column monitoring are demonstrated.
• Overburden monitoring gives the ability to characterize and monitor in time-lapse.
• Sensitivity of data and density of data to demonstrate no leakage are beginning to be considered.

EOR:

• CO₂-EOR continues to be a prospective part of storage in Norwegian and UK North Sea, GoM, and basins globally. Information and analysis continues to increase (see major summary by CSLF task force).
• The business case that would allow EOR to be profitable remains elusive. There is competition for capital – onshore first in USA, or other potential energy projects or alternative ways of recovery; delay in payback.
• There are timing and cost issues with re-use of infrastructure offshore – e.g. Norway
• Access to CO₂ will stimulate EOR projects.

Infrastructure:

• Policy approach will shift from individual projects to infrastructure, e.g. Alberta Carbon Trunk Line.
• What are the economies of scale for infrastructure and how can cost be reduced?
• Subsea solutions are coming for adding CO₂-EOR to existing platforms. Components exist, but they need to be qualified for use with CO
• Salt and shale ductility, and bentonite plugs can be used for sealing P&A wells.
• Many options exist for new and reused infrastructure and will be very site specific.
• There is a need for clear regulation in US offshore.

Recommendations:

• Design wells to release CO₂ for research purposes.
• Learn from the USA’s experience in re-use of wells for CO₂-EOR.
• Tools are needed for assessing infrastructure.
• More communication with offshore infrastructure owners is needed.
• More communication with institutions such as governments is needed on infrastructure.
• Communicate the importance of CCS for developing countries to entities such as the Green Climate Fund showing the good example in South Africa.
• Address data gaps.
• Qualify subsea system components for use with CO