A multiscale analysis of a fracture pattern in granite: A case study of the Tamariu granite, Catalunya, Spain

Abstract

Please cite this article as: bertrand, L., geraud, Y., Le Garzic, E., Place, J., Diraison, M., Walter, B., Haffen, S., A multiscale analysis of a fracture pattern in granite: A case study of the Tamariu granite,The in-depth investigation of fractured reservoirs is mainly limited to geophysical data that 2 is in 3D and mostly on the scale of hundred meters to several kilometers or boreholes data that 3 is in 1D and at meter to lower scale. The study of outcropping analogs of buried reservoirs is 4 therefore a key tool for the characterization of the fault and fracture network at the reservoir 5 scale. Tamariu granite has been the subject of this study with the aim to analyze faults and 6 fractures from seismic to borehole scale. With the combination of satellite picture at different 7 resolution and field study, we perform a statistical analysis focused of the length and 8 orientation from infra centimeter crack to hundred kilometer length fault. On the whole range 9 of scale studied, i.e. on 7 orders of magnitude, we have defined a length distribution following 10 a power-law with an exponent a= -2. On the contrary to the length that can be modeled with a 11 unique law, the orientation data shows a variation depending on the scale of observation: as 12 the fault and fracture sets are suitable from the regional faults to the centimeter crack, the 13 proportion of the sets varies at each scale of observation.

Tectonic interpretation of the connectivity of a multiscale fracture system in limestone

“…However, relatively small‐scale fractures can form during later phases of tectonism [ de Joussineau and Aydin , ; Park et al , ]. A likely universal scaling behavior may exist in a multiscale fracture system [ Odling et al , ; Marrett et al , ; Bour et al , ; Du Bernard et al , ; Bertrand et al , ], whereas inconsistent scaling exponents separated by characteristic lengths can also occur [ Ouillon et al , ; Hunsdale and Sanderson , ; de Joussineau and Aydin , ; Putz‐Perrier and Sanderson , ; Davy et al , ]. A break in scaling may be caused by the different growth mechanisms of jointing and faulting [ Pollard and Segall , ; de Joussineau and Aydin , ], the influence of lithological layering [ Ouillon et al , ; Hunsdale and Sanderson , ; Odling et al , ; Putz‐Perrier and Sanderson , ], and the nature of driving forces (i.e., boundary or body forces) associated with distinct spatial organization of strains [ Bonnet et al , ; Davy et al , ].…”

Influence of Landscape Coverage on Measuring Spatial and Length Properties of Rock Fracture Networks: Insights from Numerical Simulation

“…Actually we can also see from Fig. 5b that the landscape coverage can lead to a curvature at the small scale in the density distribution of fracture lengths, which may be related to the socalled ''truncation effect'' (Pickering et al 1995;Bonnet et al 2001) that is always present in the length distribution plot of outcrop data (Davy 1993;Odling 1997;Odling et al 1999;Bour et al 2002;Davy et al 2010;Le Garzic et al 2011;Bertrand et al 2015;Lei et al 2015;Lei and Wang 2016).…”

“…Aerial photographs are instantaneous records of ground details taken at heights ranging from tens of meters to hundreds of kilometres using, e.g. airplanes (Reed 1940;Ray 1984), helicopters (Odling 1997), or satellites (Holland et al 2009;Bertrand et al 2015). This technique allows researchers to capture geological features at different length scales, especially those large-scale structures (Maerten et al 2001;Watkins et al 2015).…”

Interaction between hydraulic fractures and natural fractures: current status and prospective directions

“…These fracture modes describe the mechanical failure of geological brittle discontinuities at multiple scales, for example, micro-, meso-to macro-laboratory and field scales (e.g., this study; Einstein and Dershowitz 1990; Rutledge and Phillips 2003;Maxwell et al 2009) and mega-field scales (e.g., Ayalew et al 2004;Kolawole et al 2018b). They are also found to characterize brittle deformation in geological materials of varying mechanical strengths such as unconsolidated sediments (e.g., Kolawole et al 2017Kolawole et al , 2018b, sedimentary rocks (e.g., , and hard rocks (e.g., Segall and Pollard 1983;Katz and Reches 2004;Bertrand et al 2015;Kolawole et al 2018c). However, this paper only considers the micro-, meso-to macroscale fracturing of reservoir rocks, and the classic fracture modes (mode-1 to 3) encompass the range of mechanical behavior that characterize HF-NF interactions discussed in this paper.…”