The Ngcas Project—Assessing the Potential for Eor and CO 2 Storage at the Forties Oilfield, Offshore UK

This chapter discusses the Next Generation Capture and Storage (NGCAS) project that has the potential to store underground 2 million tonnes of CO 2 , approximately half the annual CO 2 emissions from the Grangemouth refinery and petrochemicals complex near Edinburgh, Scotland. The investigations on this project concludes 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 water alternating gas (WAG) process and CO 2 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 modeling was then used to assess the risks of CO 2 escape. It was concluded that the geological risks of CO 2 escape were negligible, but it was not possible to analyze the chances of CO 2 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.