Pore-scale description of fluid distribution and displacement. Relative permeability and extension of Darcy's law to multi-phase flow. Fractional flow theory and displacement efficiency. Heterogeneity and sweep efficiency. Estimation of field recovery factors. Gravity stabilized displacements. Water and gas coning for vertical and horizontal wells. Decline curve analysis. Natural water influx and aquifer history matching. Pseudo-relative permeability and capillary pressure, calculation of dynamic and vertical equilibrium pseudos. Use of pseudo functions in reservoir simulation.