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Stress Effects on Flow and Transport in Three‐Dimensional Fracture Networks
Author(s) -
Sweeney M. R.,
Hyman J. D.
Publication year - 2020
Publication title -
journal of geophysical research: solid earth
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.983
H-Index - 232
eISSN - 2169-9356
pISSN - 2169-9313
DOI - 10.1029/2020jb019754
Subject(s) - flow (mathematics) , fracture (geology) , tortuosity , mechanics , channelized , geology , fluid dynamics , flow network , stress (linguistics) , geomechanics , external flow , eulerian path , geotechnical engineering , physics , computer science , mathematics , lagrangian , mathematical optimization , mathematical analysis , telecommunications , linguistics , philosophy , porosity
We investigate the effects of various external stress regimes on fracture apertures, fluid flow, and solute transport in three‐dimensional fracture networks. We use well‐established geomechanics equations coupled with discrete fracture network modeling to characterize changes in primary flow paths within a complex network as a function of stress magnitude and orientation. These changes manifest in the alterations of the fluid flow field and are measured in terms of Eulerian and Lagrangian flow observables including solute transport, which is a key problem in many hydrologic applications. Changes in primary flow paths affect the solute transport in the network by promoting anomalously early arrival or long tailing behavior. However, early time arrival is not ubiquitous in anisotropically stressed networks and in most cases there is a delayed arrival of solute, which is attributed to (i) the presence of low‐velocity zones normal to the flow direction, (ii) the angle between flow direction and major compressive principal stress directions, and (iii) changes in the primary flow paths (i.e., increases in tortuosity and active network structure). Overall, flows become more channelized in anisotropically stressed fracture networks than in unstressed and isotropically stressed networks.