Seismic Detection and Characterization of a CO2 Flood in Ardley Coals, Alberta, Canada

Michael Jason McCrank

At the Alder Flats pilot project, 180 tonnes of gaseous CO2 was injected into the Ardley Coals at a depth of 0.4 km to test enhanced coalbed methane production, as well as carbon sequestration in coals. This thesis discusses the seismic monitoring program which was executed to image the CO2 flood. Prior to commencement of CO2 injection, two preliminary 2D surveys were conducted in order to assist in designing a third 3D survey which was acquired after CO2 injection. Poststack inversion of the 3D vertical component data showed a low acoustic impedance anomaly up-dip and along strike of the preferential fluid pathway in the target coal zone. The size and location of the anomaly concurs with the expected imprint of the injected CO2 and it has been interpreted as the CO2 flood. The magnitude of the acoustic impedance anomaly suggests that a reduction in the elastic stiffness of the coal matrix frame may have been detected.