Preparing for experimental CO₂ injection: Geology of the site

J. Helen Isaac, Donald C. Lawton

We studied the geological properties of three prospective experimental CO₂ injection zones in the study area in Southern Alberta. The primary target is the Basal Belly River Formation, with secondary targets in the Medicine Hat and Second White Speckled Shale formations, which are at depths of about 285 m, 475 m and 710 m, respectively, below the surface.

We correlated well logs in the immediate area of interest with well logs from a well having a lithology log and from wells with Basal Belly River production. We calibrated the gamma ray logs in the top of the Pakowki Formation so that the average values were consistent in all of the well logs. We then used the gamma ray logs to assess reservoir continuity and sand/shale content in the Belly River Formation above the proposed injection zone and to estimate the sealing properties of this formation.

Based upon our interpretation of the gamma ray logs, it seems probable that the Belly River Formation will have sufficient shale content to be a seal in the area of interest.