In double‐porosity and multiple continuum models the fractured rock domain can be simplified as two overlapping continua, one for the matrix block system and the other for the fracture network. In this case, it is necessary to define an exchange term accounting for the transfer of fluid and solute masses between the two continua. A newly derived geometric parameter appears in the fluid exchange term, and is valid for any point‐centered block. The geometric parameter is more general and has a clear physical meaning. It is a function of both the shape and the size of the matrix block and agrees well with the double porosity model. The geometric center and conductance of the element is different under the quasi‐steady state compared to the steady state. Quasi‐steady condition is more suitable than steady state condition for modeling fractured media.