In this work, an efficient compositional framework is developed to simulate CO2 storage in saline aquifers with complex geological geometries during a lifelong injection and migration process. The novelty of the development is that essential physics for CO2 trapping are considered by a parametrization method.
The numerical framework considers essential hydrodynamic physics, including hysteresis, dissolution and capillarity, by means of parameterized space to improve the computation efficiency. Those essential trapping physics are translated into parameterized spaces during an offline stage before simulation starts. Among them, the hysteresis behavior of constitutive relations is captured by the surfaces created from bounding and scanning curves, on which relative permeability and capillarity pressure are determined directly with a pair of saturation and turning point values.On the other hand, the new development allows for simulation of realistic reservoir models with complex geological features by implementing in corner point gird. The extension to corner point grid is validated by comparing simulation results obtained from the cartesian box and the converted corner-point grid of the same geometry, and it is applied to a field scale reservoir eventually.
A set of sensitivity analysis reveals the roles of various physical effects and their interactions in CO2 trapping in a realistic reservoir model, apart from the investigation on the impact of migration path, linear trapping coefficient and depth. The results show the proposed compositional framework casts a promising approach to predict the migration of CO2 plume, and to assess the amount of CO2 trapped by different trapping mechanisms in realistic field-scale reservoirs.