Fracture Simulation and Multi-Directional Rock Quality Designation

Abstract

A simple fracture network model is proposed based on the negative exponential distribution of the discontinuities in all directions. In the fracture generating procedure the midpoint coordinates of each fracture is generated by a uniform distribution function; the fracture directions are simulated by normal probability distributions and the fracture lengths are derived from a logarithmic-normal distribution. Three different sets of fractures are presented on a planar surface with different random seeds. The main purpose of this paper is to asses the rock quality designation, (RQD), on the basis of one, two and three directional fracture sets. However, all of the previous studies up to date theoretically or practically were confined to one direction only. A graphical procedure is presented for depicting the population estimate of the average number of discontinuities along a scanline. The substitution of this estimate into the relevant RQD equation provides the rock quality estimation in a better representative manner than the classical estimates.