Geologic fractures arrangement in Miocene rocks from Mexico basin

Abstract

The study of fracture arrangement is important for the understanding of fluid flow and has a wide application in several areas as slope stability analysis, geothermal fields, deep aquifers and oil exploration. The facture arrangement is an essential characteristic of the spatial distribution of the fractures, although the relation of the spatial arrangement of fractures with variables such as the rock type, the kilometric faults, and structural inheritance is unknowns. We explore de influence of these variables in the facture arrangement through of detail study of Miocene rocks in the Mexico basin.  The Miocene rocks in the Mexico Basin are affected by three fracture systems oriented NE-SW, NNW-SSE and ~E-W. All fracture families present a cluster array, where the degree of clustering is related to the rock type that constitute the Miocene volcanic succession (lava flows and volcaniclastic deposits). In addition, the intensity of fracturing is stronger in lava flows than the volcaniclastic deposits, with an inverse relationship to the degree of clustering (Lyapunov Exponent). The F1 family (NE-SW) has groups of fractures characterized by a fractal distribution in mesoscopic scale. Meanwhile, the fractures F2 (NNW-SSE) present groups that are associated with mechanical anisotropy in pre-Miocene rocks. This phenomenon is related to structural inheritance and/or reactivation. Finally, the fractures F3 (~E-W) form groups with a random distribution.