This paper describes a passive seismic imaging case study to track gas movement during CO2 injection in the Weyburn Field, Saskatchewan, Canada. The project is part of a multi-disciplinary investigation of CO2 sequestration. A monitoring array of 8 triaxial geophones was permanently deployed in an abandoned well, to monitor induced seismicity in the field.

Induced microseismic events were recorded immediately following the start of CO2 injection in a well 50 m away from the array. The events clustered in a discrete region extending from the injection well to a neighbouring horizontal production well. Production data from this horizontal well indicated significant increases in gas production at the same time. This case study demonstrates the applicability of imaging gas injection with passive seismic monitoring, for both CO2 sequestration and enhanced oil recovery.

S.C. Maxwell* Engineering Seismology Group Canada Inc., D.J. White,
Geological Survey of Canada, and H. Fabriol, Bureau de Recherches
Géologiques et Minières, France