Potential for storage of carbon dioxide in the rocks beneath the East Irish Sea

This report considers the potential for storing CO2 in the East Irish Sea Basin, which lies between the Isle of Man and the west coast of Cumbria, Lancashire and North Wales. The East Irish Sea Basin has good potential to store CO2 in the Ormskirk Sandstone (upper Sherwood Sandstone Group), which contains oil and gas fields that prove its ability to store buoyant fluids for millions of years. The Mercia Mudstone Group forms an effective cap rock above the Ormskirk Sandstone. The best potential is likely to be in the larger gas fields such as Morecambe South and North when they are depleted. The calculated CO2 storage capacity in the oil and gas fields of the East Irish Sea Basin is approximately 1047 million tonnes. Further storage potential may exist in non-hydrocarbon-bearing closed structures in the Ormskirk Sandstone. The total storage capacity of these structures is estimated to be 630 million tonnes. However, the very fact that they do not contain hydrocarbons suggests the possibility that they may not be gas-tight.