Pembina Cardium CO₂ monitoring project: Timelapse seismic analysis

Abdullah A. Alshuhail, Donald C. Lawton, Louis Chabot

Time-lapse analysis of the surface seismic dataset at the Violet Grove CO₂-EOR pilot project site shows no significant anomaly that can be attributed to the injected supercritical CO₂ between Phase I (March 2005) and Phase III (March 2007) of the project. However, the fixed-array vertical seismic profile (VSP) dataset exhibits small amplitude variations that may be associated with the CO₂ plume. The time-lapse analysis referred to here is based on the observation of amplitude and traveltime variations after the injection of approximately 40,000 t of CO₂ into the 1650 m deep, 20 m thick Cardium Formation over a period of two years. The ongoing analysis suggests that it would be hard to detect the CO₂ plume due to its being contained in very thin layers of relatively permeable sandstone members of the Cardium Formation. The seismic data, however, suggests that no leakage of CO₂ is taking place into shallower formations.