Scientists at the University of Strathclyde have secured funding for a four-year project to study the ability of complex rock strata beneath the North Sea to trap carbon dioxide emissions (CO₂) securely.
Their findings will help to provide the tools for selecting the most suitable CO₂ storage sites as part of the large-scale development of carbon capture and storage, a key climate change technology. These tools could also greatly expand the potential for CO₂ storage worldwide.
The study will look at how CO₂, when injected into rocks deep below ground, could migrate upwards through the overlying strata, or overburden. The greenhouse gas can become trapped by dissolving into water-filled spaces between the rock grains. In more complex geology, where the fluids flow through complex pathways, there may be more potential for trapping CO₂ as it rises, thereby minimising the risk of it escaping to the surface.
However, fault zones cutting geological layers could potentially provide shortcuts past the layers where CO₂ could be trapped. The project team will investigate how the faults and rock strata interact to change the pathways for CO₂ flow through the overburden.
The researchers from Strathclyde, an SCCS partner institute, will work with fellow scientists from the Universities of Cambridge and Imperial, and the British Geological Survey as part of a larger research project funded by Natural Environment Research Council (NERC).
Professor Zoe Shipton, University of Strathclyde, who will lead the fault zone study, said:
The rock types found within fault zones will change depending on the rocks that they cut. By understanding how the fault rock types influence mechanisms such as capillary trapping, dissolution of CO₂ in water and migration pathways, our work can guide strategies for quantifying and reducing the risks of CO₂ leakage from geological storage sites.
We will construct simplified models of flow along layered strata with cross-cutting faults, alongside our partners’ laboratory analogue experiments, in order to constrain the effect of geological complexity on the fate of CO₂ leaking from a subsurface storage site.
The researchers will also look at real-life examples of CO₂ storage – for example, Norway’s Sleipner project in the North Sea – to test their findings.
The UK is geologically well placed to implement offshore CO₂ storage, with many potential reservoirs in the geology beneath the UK’s North Sea.
The project runs from May 2016 to April 2020. More details