Estimation of tortuosity of fluid flow through a single fracture

Tortuosity of fluid flow through a fracture is mainly caused by the geometry of the fracture surface and contact condition. In addition, it causes the deviation from the cubic law of fracture permeability. In this study, to estimate the tortuosity, several physical experiments and numerical simulations to visualize the streamlines were carried out for the water flow through interlocking fractures and non-interlocking fractures. These fractures were artificially prepared by using a fractal model to control the fractal parameters and interlocking parameter. Furthermore, the tortuosity was discussed in relation to the fractal parameters, interlocking parameter, and contact area ratio. Consequently, the behaviour of fluid flow through the fractures was clarified, and the effects of those parameters on tortuosity were clarified. The obtained results can give a basic knowledge of the fluid flow through a fracture and will be helpful to estimate the fracture permeability used for reservoir simulation and well test analysis.