Unconventional reservoirs, such as shale-gas or tight-oil reservoirs, are generally highly fractured, including hydraulic fractures, stimulated and non-stimulated natural fractures of various sizes, embedded in low-permeability formations. One of the main production mechanisms in unconventional reservoirs is the flow exchange between matrix and fracture media. However, due to extremely-low matrix permeability, the matrix/fracture exchange is very slow and the transient flow may last several to tens of years, i.e. almost the entire production life. The commonly-used dual-porosity modelling approach involves a computation of pseudo-steady-state matrix-fracture transfers with homogenized fluid and flow properties within the matrix medium. This kind of model clearly fails to handle the long-lasting matrix/fracture interaction in very-low permeability reservoirs, especially for multi-pahse flow with phase change problems. Moreover, a dual-porosity model is not adapted for the simulation of matrix/fracture exchange when fractures are described by a DFN (Discrete Fracture Network). This paper presents an EDFM (Embedded Discrete Fracture Model) based on the MINC (Multiple INteracting Continua) proximity function to overcome this insufficiency of the conventional dual-porosity model.