Fractal and multifractal analysis of fractured geological media: surfacesubsurface correlation
One of the main points of interest in fractured media analysis arises from the need to characterise and model fracture patterns, within the framework of the current problem of identifying a site for the location of a deep geological nuclear fuel or waste disposal facility. Preservation of the environment during this characterisation is an important requirement. Thus, preliminary surface studies are preferred to drilling. Relatively recently, fractal geometry techniques have begun to be applied to the analysis of fractured geological media. Many of these techniques have used spatial data, in the form of surface maps of fractures and outcrops, or, when available, borehole geophysical records. Studies by several authors have shown that scaling invariance exists over a wide range of scales, both in geometrical data sets and in geophysical variables (fracture density, hydraulic conductivity, resistivity, etc.) measured in depth. However, the real question is concerned with the fracture field in the entire rock mass. Is it possible to characterise the three-dimensional fracture system taking into account the scale invariance derived by surface or borehole analysis?. This paper is aimed at solving this problem. A methodology, called the inverse box counting algorithm, is developed, to compute the multifractal spectrum. First, the fracture patterns are characterised with respect to their scaling behaviour. Then, a structural inference of the stochastic three-dimensional fracture network is presented. Results of the application of this methodology, at the El Berrocal site, a granite batholite in Toledo (Spain), are presented, and used to simulate the three-dimensional fracture network.
fracture media fracture density fracture simulation hidrobap project