Predicting multiphase and multicomponent flow and transport processes in the Earth’s subsurface remains an open challenge with direct implications on a number of environmental, industrial and biological processes, including the infiltration of water through the vadose zone, the contamination of underground water bodies by non-aqueous phase liquids (NAPLs), geologic CO2 storage, enhanced oil recovery, transport and biochemical controls on microbial activity in the subsurface, or the formation and dissociation of methane hydrates in permafrost regions and in ocean sediments. Multiphase, multi-component flows lie at the heart of current challenges in energy technologies, such as geothermal energy systems and unconventional hydrocarbon resources. Conventional continuum-scale models often oversimplify important pore-scale fluid displacement and transport mechanisms, such as wetting and capillarity effects, mechanical dispersion and its interaction with molecular diffusion, chemical reactions and biological processes, or formation heterogeneities. In addition, multiphase flow is often viscously or gravitationally unstable, and mass transfer between fluid phases can result in non-trivial phase behavior. Model inaccuracies lead to uncertainties when applied to field-scale operations. In this session we wish to bring together experimental and modeling studies that address these challenges, including pore-scale visualization techniques, numerical simulation tools and theoretical approaches allowing modeling andbetter upscaling the pore scale processes mentioned above. We are especially interested in submissions that present innovative methods and codes for pore scale mutiphase flow modeling in porous and fractured subsurface media, characterize the rich phenomenology of multiphase flows from the pore scale and up, using either experimental or numerical approaches, or link pore-scale fluid processes to continuum-scale models and their associated constitutive relationships, as well as offer alternatives to and discussions on the limitations to conventional continuum-scale models. We also welcome studies addressing deformable porous media and the interaction between multiphase flow and the deformation of the solid phase.