Journal of the Korean Society of Mineral and Energy Resources Engineers ISSN:2288-0291(Print) 2288-2790(Online) 한국자원공학회지

In naturally fractured media, topological characteristics of fracture networks show fractal geometry. Several geological surveys have shown that fractal dimensions of fracture networks have different values with length scale and fractured media have randomness. In this study, we investigated pressure transient behaviors in fractured media with multi-fractal characteristics. After generating random fracture networks following a power-law length distribution, we extract infinite clusters that affect fluid flow in the networks. When the length exponent is between 2 and 3, the fracture networks have two different fractal dimensions separated by a critical radius. As the results of numerical flow simulations, pressure transient behavior shows two distinguished fractal characteristics due to the multi-fractal geometry. Fractal diffusion slowdown is small within the critical radius because the behavior of fluid flow is governed by a few long fractures only. On the contrary, it becomes large over the critical radius because the fracture networks in megascopic scale have more complexity by the combined effects of all the fractures. As length exponent increases, both of fractal dimension and diffusion slowdown increase.