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.