Greensand Focused Seismic Monitoring for Offshore CO2 Pilot Injection

Paper presented at the GET 22 The Hague, Netherland, October 2022, presented by A. Szabados1. Written by: A. Szabados1, H. Al Khatib2, N. Ahmad3, K. Dominek3, O. Burachok4, T. Roth 4, N. H. Schovsbo5 1 Wintershall Dea International GmbH, 2 SpotLight SAS, 3 INEOS Energy Denmark ApS, 4 Wintershall Dea AG; 5 Geological Survey of Denmark and Greenland (GEUS).


The Greensand consortium, led by INEOS Energy Denmark, is preparing a CO2 pilot injection to inject up to 15.000 tons of CO2 into the depleted Nini West oil field, Danish North Sea. The operation lasts 90 days and include 14 shipments of CO2 to the Nini site. The injection is cyclic and will be accompanied by three focused seismic acquisitions with the objective to detect and monitor the CO2 plume.

Modelling done implies that the seismic surveys can detect injected CO2 in the reservoir exceeding 4% saturation. The maximum CO2 saturation at the injection well after the last injection cycle will reach up to 55% and will radially migrate up-dip, being dissolved in formation brine and trapped in the reservoir.

The objective of the planned spot seismic acquisition surveys is to proof the concept offshore of such focused and repeated seismic acquisitions which have the potential to replace conventional 4D seismic for CO2 plume migration monitoring requirements, reducing the monitoring costs and environmental footprint during the entire storage field life.

If successful, this focused seismic monitoring concept would have positive impact on the commercial viability and environmental footprint of the Greensand project and possibly other offshore CCS site as well.