Issue 51

R. Basirat et alii, Frattura ed Integrità Strutturale, 51 (2020) 71-80; DOI: 10.3221/IGF-ESIS.51.06 71 Scaling geological fracture network from a micro to a macro scale Rouhollah Basirat, Kamran Goshtasbi*, Morteza Ahmadi Faculty of Engineering, Tarbiat Modares University, Tehran, Iran goshtasb@modares.ac.ir A BSTRACT . Characterizing fracture systems at various scales, modeling fracture distributions, and clarifying scale relations that correlate total fracture systems are of paramount importance in geology, mining, civil engineering, and petroleum engineering. In this paper, the conditions of fracture network geometry are investigated in a field scale (about 100 m) and a core sample scale (several centimeters). To achieve this purpose, field surveys and coring of rock outcrops were performed in the Asmari Formation of Iran. Fractures were manually sampled from rock outcrops on the field scale while micro-fractures were surveyed using CT-scan images of core samples on a small scale. To compare the fracture network geometry, two perspectives of fractal dimensions and orientation of fractures were used. The results showed that the fractal dimension has the same value in both field and core scales and the orientation of the fractures is similar in both scales. Therefore, it can be claimed that in the Asmari Formation of Iran the structure of the fracture network is similar in two studied scales. K EYWORDS . Asmari Formation; CT-scan; Fractal Dimension; Fracture System; Scaling Citation: Basirat, R., Goshtasbi, K., Ahmadi, M., Scaling geological fracture network from a micro to a macro scale, Frattura ed Integrità Strutturale, 51 (2020) 71-80. Received: 16.09.2019 Accepted: 14.10.2019 Published: 01.01.2020 Copyright: © 2020 This is an open access article under the terms of the CC-BY 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. I NTRODUCTION ock fractures are observed at various scales ranging from several micrometers to hundreds of kilometers [1, 2] and often exhibit high scale invariance and self-similarity [3-6]. Therefore, recognizing the scaling behavior of natural fracture systems opens the possibility for characterization of macro-scale properties of fractured rock/medium from a relatively smaller sampled model [7]. Fractal concepts can be applied to these issues in a variety of ways. A fractal distribution is the only statistical distribution that is scale-invariant [8]. One of the most remarkable features of the concept of fractal introduced by Mandelbrot [9] is the description and understanding of self-similarities. Self-similarity refers to the well-known observation that the Earth’s morphology looks the same at a variety of scales. This feature is used in numerous investigations including breakage and fragmentation [10], the interaction of fracture growth processes correlations from macro-scale frameworks to micro-scale fabrics [1, 3], tectonic interpretation of the connectivity of a multiscale fracture system [11], fault and fractures patterns [12- 15], modeling porous media by scaling mass, pore space, and pore surface [16], the terrain fault distribution [17], and clustering of earthquakes [18, 19]. R