Characterization of 3D Printed Fracture Networks

Abstract

Tracer testing has been used to obtain hydraulic properties in a reservoir system and may help characterize the fracture networks inside the reservoir. Numerous studies at various scales have shown that the distribution of many fracture properties (i.e., length, displacement) follows a power law scaling with some cutoffs. Fractal dimension is useful to evaluate the geometric characteristics of fracture networks. We studied mass transport in a fracture network where fracture lengths are given by a power law with maximum and minimum length. Effects of fractal dimension of fracture lengths on mass transport were investigated by particle tracking simulations and laboratory flow experiments in a fractured flow model. The numerical simulation results indicate that the fractal nature of the fracture length results in non-Fickian behavior on tracer responses. In the laboratory flow experiments, a 3D printer was used to create artificial fracture network models with different fractal dimensions. The experimental tracer responses of the 3D printed fracture model show similar features to the results by numerical simulation. A challenge of the printing process was the limited resolution of the 3D printer and the solubility of the supporting wax.