ABSTRACT
This chapter considers the shale-based fluids, that is, liquid-rich shales or other types of reservoir fluids such as gas condensates or wet gases or dry gases present in particularly low permeability or nano Darcy range porous media. Commercial compositional reservoir simulators that are typically used in the petroleum industry do not have the option of incorporating porous media effects on phase behavior. The delay in gas breakthrough and extended undersaturated conditions has important consequences on estimated ultimate recovery of oil which has been adequately demonstrated by inclusion of capillary pressures in numerical reservoir simulations. The application of the capillary pressure equation is the inclusion in phase behavior calculations for unconventional systems to take into account the influence of nano-sized pores. The retrograde condensate may have some mobility after reaching critical condensate saturation, the recovery of the condensate in shale reservoirs may be more severely impacted than in conventional gas condensate reservoirs.
