Realistic models for saturation, capillary pressure and relative permeability s-p_c-k_r relations are essential for accurate predictions in multiphase flow simulations. The primary object of this work is to investigate their influence on geological CO₂ sequestration processes. In this work, the hysteresis effects on simulation results predicting geological CO₂ storage are investigated on a synthetic 2D model and a geological setting built according to Aneth demonstration site. Simulation results showed that hysteretic relative permeability model should be included while the residual trapping mechanism is under investigation. The effects of hysteresis and WAG schemes were studied with a series of numerical simulations on a geological setting based on Aneth site. Our simulations demonstrate that the hysteresis effect is strong on residual trapping mechanisms and there is no significant effects of alternative WAG schemes for long term residual trapping in our conceptual model. The effects of WAG schemes and hysteresis are weak on dissolution trapping mechanisms.

Precise descriptions of saturation, capillary pressure and relative permeability s-p_c-k_r relations are essential for predictions and simulations on multiphase flow system. The primary object of this work is to investigate their influence on geological CO₂ sequestration processes. Five types of commonly used s-p_c-k_r relations are examined in this study. Simulation results show significant influences of s-p_c-k_r relations on 1) the location and saturation of displacement fronts, 2) buoyancy driven migration speed, 3) horizontal spreading distance and the rate of dissolution of supercritical CO₂. The effects of capillary pressure on the horizontal spreading of supercritical CO₂ plume and its dissolution rate was resolved in this study for the 1st time in literatures. Simulation results of subsurface CO₂ storage suggest that that careful selection of s-p_c-k_r relations and calibration methods are essential for accurate predictions.