Model Instance Title:
CASSEM Hypothetical Leakage  
Model Instance Short Name:
The far-field effects of CO2 storage on onshore potable groundwater systems is examined for a hypothetical injection site within the Sherwood Sandstone Group (SSG) on the East Lincolnshire coastline, United Kingdom (UK). Using the quasi-three dimensional object-orientated groundwater flow model ZOOMQ3D, supported by conceptualisation and aquifer parameterisation of the wider hydrogeological setting, injection of 15 Mt/year of CO2 for 20 years (60 Ml/day groundwater equivalent) into the aquifer at depth is simulated. Model scenarios are carried out which test the dissipation of pressures up-dip within the storage formation. When applying typical vertical hydraulic conductivity of 10−6 m/day to the Mercia Mudstone Group (MMG) caprock groundwater pressure heads in the shallow confined SSG aquifer, 60 km up dip, where it is used for potable water supply, increase by 0.01–10 m. Groundwater levels within the unconfined aquifer, 80–100 km up-dip from the injection zone, increase by <0.01–1 m with a corresponding increase in river flows of approximately 1.7%. Two important points are observed, firstly that the degree of impact on shallow groundwater systems is highly sensitive to the vertical leakage assigned to the caprock. When the leakage co-efficient is increased by one order of magnitude groundwater heads in the potable aquifer are reduced by two orders of magnitude. Secondly, that the response of groundwater pressure heads to injection is rapid, as is the subsequent recovery. Using a groundwater model, in addition to detailed reservoir modelling, provides a useful tool to assess the potential scale of impact of CO2 storage on shallow groundwater systems and can be used to aid the regulation of such operations  
Creation/Publication Date:
Hazards Floods   
Contact Details:
Andrew Barkwith   British Geological Survey   UK  
Model Code Name:
Time Interval Covered:
from: 01-Jan-1970   to: 31-Dec-2090
Spatial Extent:
Bounding Box (Lat/Long WGS84):
West: -1.256   East: 0.643   South: 53   North: 53.602  
Scope of Vertical Extent: Permo-Triassic Sandstone  
Vertical Extent (metres above OD) Maximum: -400   Minimum: 200    
Spatial Reference Systems of Datasets:
Horizontal Reference System: WGS 84
Vertical Datum: mean sea level depth
Vertical Units: metre
Grid Resolution:
Spacing XSpacing YSpacing ZCells XCells YCells Z
1000   1000     125   70   3  

Time step interval: month   Time step value: 4
Additional information (science questions addressed, assumptions etc.):
Science Question   What impact does the injection of supercritical CO2 in the Sherwood Sandstone Group aquifer have on the groundwater system up gradient?  
Boundary Condition   No flow around model; vertical leakage specified where Mercia Mudstone overlies the Sherwood Sandstone Group  
Initial Condition   Steady state heads  
Input Dataset NameVersionURL LinkParameterValueUnits
Input Data          
    Geometry of model      
    Hydraulic conductivity      
    Storage coefficient      
    Pumping rate      
Output Dataset NameVersionURL LinkParameterValueUnits
Output Data          
    Grounmdwater head      
    Flow into and out of Mercia Mudstone      
Documents and Published Papers available for this model instance:
Bricker, S.H.; Barkwith, A.; MacDonald, A.M.; Hughes, A.G.; Smith, M.   Effects of CO2 injection on shallow groundwater resources : a hypothetical case study in the Sherwood Sandstone aquifer   2012