A computer-implemented method for estimating an upscaled directional permeability of a formation, the method comprising: receiving a discrete fracture network, the DFN being a plurality of rock fractures and a location, size, orientation and aperture of each of the rock fractures; aligning the DFN in a predetermined orientation or direction; cropping the DFN to a predetermined size having boundaries; identifying a fracture plane or fracture planes that are connected with each other and establish a path between the boundaries of the cropped DFN; creating a pipe model of the identified fracture or fractures (61, 62, 63, 64), the pipe model comprising a node (71, 72, 73) at an intersection (65, 66, 67) of fracture planes and a conduit (75, 76) connecting two nodes together such that one or more conduits alone or in combination establish the path between the boundaries of the cropped DFN, the pipe model further comprising a node at each conduit intersecting a boundary, the method is characterized by further comprising: creating a system of equations representing flows through the conduits; applying boundary conditions to the system of equations; solving the system of equations for steady-state flow to estimate the upscaled directional permeability of the formation; iterating the aligning, cropping, identifying, creating a pipe model, creating a system of equations, applying and solving for another orientation or direction when the upscaled directional permeability is wanted for the another orientation or direction; transmitting a signal comprising the upscaled directional permeability to a signal receiving device using an output interface; wherein the aligning, cropping, identifying, creating a pipe model, creating a system of equations, applying and solving are performed using a processor; wherein the upscaled directional permeability comprises a plurality of upscaled directional permeability values for a plurality of orientations or directions; and wherein the method further comprises plotting a plot illustrating the plurality of upscaled directional permeability values for the plurality of orientations or directions. receiving a discrete fracture network, the DFN being a plurality of rock fractures and a location, size, orientation and aperture of each of the rock fractures; aligning the DFN in a predetermined orientation or direction; cropping the DFN to a predetermined size having boundaries; identifying a fracture plane or fracture planes that are connected with each other and establish a path between the boundaries of the cropped DFN; creating a pipe model of the identified fracture or fractures (61, 62, 63, 64), the pipe model comprising a node (71, 72, 73) at an intersection (65, 66, 67) of fracture planes and a conduit (75, 76) connecting two nodes together such that one or more conduits alone or in combination establish the path between the boundaries of the cropped DFN, the pipe model further comprising a node at each conduit intersecting a boundary, the method is characterized by further comprising: creating a system of equations representing flows through the conduits; applying boundary conditions to the system of equations; solving the system of equations for steady-state flow to estimate the upscaled directional permeability of the formation; iterating the aligning, cropping, identifying, creating a pipe model, creating a system of equations, applying and solving for another orientation or direction when the upscaled directional permeability is wanted for the another orientation or direction; transmitting a signal comprising the upscaled directional permeability to a signal receiving device using an output interface; wherein the aligning, cropping, identifying, creating a pipe model, creating a system of equations, applying and solving are performed using a processor; wherein the upscaled directional permeability comprises a plurality of upscaled directional permeability values for a plurality of orientations or directions; and wherein the method further comprises plotting a plot illustrating the plurality of upscaled directional permeability values for the plurality of orientations or directions. creating a system of equations representing flows through the conduits; applying boundary conditions to the system of equations; solving the system of equations for steady-state flow to estimate the upscaled directional permeability of the formation; iterating the aligning, cropping, identifying, creating a pipe model, creating a system of equations, applying and solving for another orientation or direction when the upscaled directional permeability is wanted for the another orientation or direction; transmitting a signal comprising the upscaled directional permeability to a signal receiving device using an output interface; wherein the aligning, cropping, identifying, creating a pipe model, creating a system of equations, applying and solving are performed using a processor; wherein the upscaled directional permeability comprises a plurality of upscaled directional permeability values for a plurality of orientations or directions; and wherein the method further comprises plotting a plot illustrating the plurality of upscaled directional permeability values for the plurality of orientations or directions.