uu.seUppsala University Publications
Change search
ReferencesLink to record
Permanent link

Direct link
Modelling stress-dependent permeability in fractured rock including effects of propagating and bending fractures
Department of Earth Science and Engineering, Imperial College, London, UK.
Show others and affiliations
2013 (English)In: International Journal of Rock Mechanics And Mining Sciences, ISSN 1365-1609, E-ISSN 1873-4545, Vol. 57, 100-112 p.Article in journal (Refereed) Published
Abstract [en]

The influence of in-situ stresses on flow processes in fractured rock is investigated using a novelmodelling approach. The combined finite-discrete element method (FEMDEM) is used to model thedeformation of a fractured rock mass. The fracture wall displacements and aperture changes aremodelled in response to uniaxial and biaxial stress states. The resultant changes in flow properties ofthe rock mass are investigated using the Complex Systems Modelling Platform (CSMPþþ). CSMPþþisused to model single-phase flow through fractures with variable aperture and a permeable rock matrix.The study is based on a geological outcrop mapping of a low density fracture pattern that includes therealism of intersections, bends and segmented features. By applying far-field (boundary) stresses to asquare region, geologically important phenomena are modelled including fracture-dependent stressheterogeneity, the re-activation of pre-existing fractures (i.e. opening, closing and shearing), thepropagation of new fractures and the development of fault zones. Flow anisotropy is investigated undervarious applied stresses and matrix permeabilities. In-situ stress conditions that encourage a closing offractures together with a more pervasive matrix-dominated flow are identified. These are comparedwith conditions supporting more localised flow where fractures are prone to dilatational shearing andcan be more easily exploited by fluids. The natural fracture geometries modelled in this work are notperfectly straight, promoting fracture segments that dilate as they shear. We have demonstrated theintroduction of several realistic processes that have an influence on natural systems: fractures canpropagate with wing cracks; there is the potential for new fractures to connect with existing fractures,thus increasing the connectivity and flow; blocks can rotate when bounded by fractures, bent fractureslead to locally different aperture development; highly heterogeneous stress distributions emergenaturally. Results presented in this work provide a mechanically rigorous demonstration that a changein the stress state can cause reactivation of pre-existing fractures and channelling of flow in criticallystressed fractures.

Place, publisher, year, edition, pages
2013. Vol. 57, 100-112 p.
Keyword [en]
Hydro-mechanical coupling, Deformation, Fracturing, Fracture-matrix, Fluid flow, Numerical simulation
National Category
Geosciences, Multidisciplinary
Identifiers
URN: urn:nbn:se:uu:diva-293669DOI: 10.1016/j.ijrmms.2012.08.002OAI: oai:DiVA.org:uu-293669DiVA: diva2:928148
Available from: 2016-05-14 Created: 2016-05-14 Last updated: 2016-06-16Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full text

Search in DiVA

By author/editor
Tsang, Chin-Fu
In the same journal
International Journal of Rock Mechanics And Mining Sciences
Geosciences, Multidisciplinary

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 73 hits
ReferencesLink to record
Permanent link

Direct link