The Ngcas Project—Assessing the Potential for Eor and CO2 Storage at the Forties Oilfield, Offshore UK

The Next Generation Capture and Storage Project studied the potential to store underground 2 million tonnes of CO2, approximately half the annual CO2 emissions from the Grangemouth refinery and petrochemicals complex near Edinburgh, Scotland. The study concluded that the best potential storage site for these emissions was the Forties oilfield in the UK sector of the North Sea. Numerical simulation indicated that enhanced oil recovery using a WAG process and CO2 as the injection gas would yield significant incremental oil. A Features-Events-Processes (FEP) identification process was used to narrow down the risks to storage at the Forties field. Numerical modelling was then used to assess the risks of CO2 escape. It was concluded that the geological risks of CO2 escape were negligible, but it was not possible to analyse the chances of CO2 escape via pre-existing wells. The wells are perceived as the main uncertainty in the analysis and it is recommended that a comprehensive risk assessment methodology for wells is developed.