Single-phase lattice Boltzmann simulations of pore-scale flow in fractured permeable media

The objective of this work is to investigate fracture flow characteristics at the pore-scale, and evaluate the influence of the adjacent permeable matrix on the fracture's permeability. We use X-ray computed microtomography to produce three-dimensional images of a fracture in a permeable medium. These images are processed and directly translated into lattices for single-phase lattice Boltzmann simulations. Three flow simulations are presented for the imaged volume, a simulation of the pore space, the fracture alone and the matrix alone. We show that the fracture permeability increases by a factor of 15.1 due to bypassing of fracture choke points through the matrix pore space. In addition, pore-scale matrix velocities were found to follow a logarithmic function of the distance from the fracture. Finally, our results are compared against previously proposed methods of estimating fracture permeability from fracture roughness, tortuosity, aperture distribution and matrix permeability.