An empirical flow model, based on the observed fracture networks and corridors of the deepwater clastic systems of Clare Basin, Ireland, shows that fracture enlargement at intersections increases the vertical flow through fracture corridors. In vertical fracture corridors, flow is dominantly controlled by fracture density and aperture, but this work also shows a significant influence from fracture intersection openings.

Only connected fracture networks contribute to field horizontal permeability, while both isolated and connected fractures contribute to vertical permeability. In this field, horizontal fracture flow needs a minimum fracture density about 4.5 m−1; below that critical density, no field horizontal fracture flow exists. For fracture aperture of 0.1 mm, field horizontal intrinsic fracture permeability can be estimated by an empirical equation: kIH(cm2) = 5×10−9d3.802 (m−1) for fracture density between 4.5 and 7 m−1; where fracture density is between 7 and 20 m−1, the empirical equation kIH (cm2) = 2×10−7d1.978 (m−1); where fracture density is above 20 m−1, kIH is close to field vertical intrinsic fracture permeability (kIV) because more and more fractures are connected to form flow channels.

The workflow introduced here estimates field scale-fracture permeability using discrete fracture networks (DFNs) for reservoir simulations from seismic and well logs. We estimated the vertical permeability of both simulated fracture networks and natural fracture networks from the sediment rock exposures in the English Lake District, estimating both vertical and horizontal intrinsic fracture permeabilties based on fracture density (d).

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