Modeling CO 2 plume migration based on calibration of injection and post‐injection pressure response at the AEP Mountaineer Project

Supercritical CO 2 injection was carried out at the AEP Mountaineer CO 2 Capture and Geological Storage Project from October 2009 until May 2011. Approximately 27 000 MT and 10 000 MT were injected into the Copper Ridge dolomite formation and Rose Run sandstone formation, respectively. A 2‐D radial‐cylindrical model based on ‘average’ conditions in the study area was developed from integration of well‐log data. STOMP‐CO 2 simulations were carried out to calibrate the observed pressure response using a trial‐and‐error procedure. This involved varying: (i) permeability near the injection well, (ii) permeability of the far‐field region, and (iii) relative permeability model coefficients. Non‐unique combinations of these parameters were found to produce similar pressure matches, but different estimates of plume migration. For the Ridge formation, excellent matches were obtained for the injection pressure/rate data at AEP‐1 and observed pressures at MW‐2, located ∼2200 feet away. Estimates of radial plume migration range between 925 and 975 ft. For the Rose Run formation, excellent matches were obtained for the injection pressure data at AEP‐2 and observed pressure at MW‐3, ∼125 feet away, although the match with MW‐1, located ∼2200 feet away, was less satisfactory. Estimates of radial plume migration range between 460 and 510 ft. The modeling approach and results presented here represent a significant and unique case study of post‐injection modeling at CO 2 storage locations – a critical aspect for successful permit closure in accordance with the EPA requirements.