Upscaling of the constitutive relationships for CO2 migration in multimodal heterogeneous formations

► A macroscopic percolation model is developed for upscaling of constitutive relations. ► Multimodal heterogeneous media with different statistical parameters are considered. ► Material proportions and k variability control the large-scale constitutive relations. ► Leverett equation may not apply for cases with background material proportion < 70%.