Fracture networks are not the only consideration of how fluids can travel through rock layers to the surface. Because of the greater pressures beneath the surface, fluid naturally
flows toward areas of lower pressure if a pathway (through fractures or between connected pore spaces) exists.
Permeability (amount of connected pore space) is measured in milliDarcies (after Darcy’s Law, which
describes how fluids flow through porous media). The rate at which a fluid
can flow through a rock, based on the amount of fluid present, pressure,
fracture presence, and rock permeability, is called conductivity