Interpretation of baseline surface seismic data at the Violet Grove CO₂ injection site, Alberta

Fuju Chen, Donald C. Lawton

Time-lapse seismic technology has been implemented in the Penn West pilot project, in west-central Alberta, Canada, to monitor the CO₂ storage in the Cardium Formation. A multi-component 3D surface seismic baseline survey was acquired in March 2003. An interpretation using both PP and PS seismic data has been made. Four horizons of Ardley, Cardium, Blackstone, and Viking Formations have been picked. At well 102/7-11-48-9, the top of Cardium Sand correlates to a weak peak at approximately 1043 ms and 1690 ms in the PP and PS survey, respectively; the top of the Blackstone Formation correlates to a strong trough at 1060 ms and 1714 ms in the PP and PS survey, respectively; There exists a small amplitude anomaly in the Cardium event around the observation well and the injection pad in the PP data. Vp/Vs values were calculated from the compression and shear sonic logs: The good reservoir of the Cardium Formation has a low Vp/Vs value (1.6-1.8); the shale above and below the Cardium Formation has a relatively high Vp/Vs value (1.8-2.0). The average Vp/Vs between Ardley and Viking horizons is approximately 2.0.