Post-Injection Monitoring and Well Abandonment Results of the Ketzin Test Site – An Essential Part for Transfer of Liability

The Ketzin pilot site (Brandenburg, Germany) was the first European on-shore CO2 storage project and has successfully demonstrated the full life-cycle of a CO2 storage site, covering all phases and fulfilling all requirements defined by the EU CCS directive (European Commission 2011). After site assessment, characterization and development from 2004 to 2008, injection operation lasted from July 2008 to August 2013. During this period, about 67 kt CO2 were safely injected into an Upper Triassic sandstone reservoir. In September 2013 the site entered the post-closure/pre-transfer phase with final handover of the liability to the competent authority in 2018. Besides continuous post-injection monitoring and post-injection field experiments, main targets of the post-closure/pre-transfer phase were the backfilling and abandonment of the wells in compliance with regulatory requirements. This paper focusses on the post-injection well-integrity monitoring and the stepwise abandonment of the wells and closure of the site.