Effect of temperature and concentration of impurities in the fluid stream on CO2 migration in the Utsira formation

Abstract A satisfying history match of CO 2 plume migration in the Sleipner field of the Utsira formation has been difficult to achieve using multiphase flow simulations. Poor modeling of plume or reservoir temperature and impurities in the CO 2 stream have been cited as a source of uncertainty in model predictions. Both of these aspects can have a large impact on the simulation results of plume migration in the Sleipner field where the injected fluid is close to the critical point of CO 2 . We have performed multiphase flow simulations in the uppermost sand layer of the Sleipner field (Layer 9) over a range of temperatures and fluid compositions in order to clarify these uncertainties. The results reveal that an increase in temperature by a few degrees and simultaneously accounting for impurities from the separation process lead to significantly improved comparison with seismic data. Between temperature and fluid composition, temperature was the most important predictor for success. The results of this study imply that the impact of temperature on model predictions has previously been underestimated. Implementation of a realistic temperature and fluid composition will lead to better prediction of plume mobility and storage capacity, which is important for screening and planning of optimal storage sites.