Work has begun on a new research project focusing on fault sealing properties and their effect on the CO₂ storage capacity of saline aquifer formations.
The project is being carried out by researchers at SCCS partner institutes, the University of Edinburgh and the British Geological Survey (BGS), with funding provided by the UK CCS Research Centre.
SCCS director, Professor Stuart Haszeldine, of the University of Edinburgh, and Dr Andy Chadwick, of BGS, are leading the project, which will seek to establish the extent to which fault seal affects CO₂ storage within aquifers by studying natural accumulations of CO₂ and methane in the Southern North Sea Basin.
Dr Chadwick said: “Naturally occurring geological faults present one of the key uncertainties in underground CO₂ storage. In storage reservoirs they can obstruct or even prevent reservoir fluid flow, which might result in unwanted pressure increase as CO₂ is injected. Faults in the reservoir topseal might provide potential pathways for the leakage of CO₂ to shallow depths. Considerable understanding of fault properties has been gained from laboratory experiments and various kinds of numerical models, but in this new project we are focusing on real field examples from the North Sea.”
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He added: “Using geological and production information from gas fields, together with high-resolution 2D and 3D seismic data, we hope to establish the key characteristics of those faults that seem to act as seals to natural gas and CO₂ flows on geological timescales, and how these differ from the faults that show evidence of having acted as pathways to fluid and gas flows. This information will help us to calibrate models and predictions of fault behaviour during CO₂ storage and, more generally, in the selection of suitable storage sites.”
The project collaborators are currently collecting data on known high CO₂ content and faulted fields across Northern Europe and in the North Sea. The team will then perform modelling of the fault seal capacity of these reservoirs. The results will be used to assess potential faulted CO₂ storage sites in the North Sea and the implications this will have for CO₂ storage capacities across the basin.