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Upscaling of Fracture Hydraulics by Means of an Oriented Correlated Stochastic Continuum Model
Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences.
2003 In: Water Resources Research, ISSN 0043-1397, Vol. 39, no 10, SBH 3 (1-13) p.Article in journal (Refereed) Published
Place, publisher, year, edition, pages
2003. Vol. 39, no 10, SBH 3 (1-13) p.
URN: urn:nbn:se:uu:diva-92871OAI: oai:DiVA.org:uu-92871DiVA: diva2:166180
Available from: 2005-03-31 Created: 2005-03-31Bibliographically approved
In thesis
1. Upscaling of Flow, Transport, and Stress-effects in Fractured Rock
Open this publication in new window or tab >>Upscaling of Flow, Transport, and Stress-effects in Fractured Rock
2005 (English)Doctoral thesis, comprehensive summary (Other academic)
Alternative title[sv]
Uppskalning av flöde och ämnestransport i sprickigt berg samt bergspänningens inverkan
Abstract [en]

One of many applications of geohydraulic modelling is assessing the suitability of a site to host a nuclear waste repository. This modelling task is complicated by scale-dependent heterogeneity and coupled thermo-hydro-mechanical (THM) processes. The objective here was to develop methods for (i) upscaling flow and transport in fractured media from detailed-scale data and (ii) accounting for THM-induced effects on regional-scale transport. An example field data set was used for demonstration.

A systematic framework was developed where equivalent properties of flow, transport, and stress-effects were estimated with discrete fracture network (DFN) modelling, at some block scale, and then transferred to a regional-scale stochastic continuum (SC) model. The selected block scale allowed a continuum approximation of flow, but not of transport. Instead, block-scale transport was quantified by transit time distributions and modelled with a particle random walk method at the regional scale.

An enhanced SC-upscaling approach was developed to reproduce the DFN flow results more simply. This required: (i) weighting of the input well-test data by their conductivity-dependent test volumes and (ii) conductivity-dependent correlation structure. Interestingly, the best-fitting correlation structure resembled the density function of DFN transmissivities.

Channelized transport, over distances exceeding the block scale, was modelled with a transport persistence length. A linear relationship was found between this persistence length and the macroscale dispersion coefficient, with a slope equal to a representative mean block-scale dispersion coefficient.

A method was also developed to combine well-test data and rock-mechanical data in estimating fracture transmissivities, and its application was demonstrated.

Finally, an overall sequential THM analysis was introduced allowing the estimation of the significance of waste-related thermo-mechanical (TM) effects on regional transport; here TM effects are calculated separately and their impact on fracture transmissivities were incorporated into the hybrid framework. For the particular case, their effects on regional-scale transport were small.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2005. 71 p.
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 35
Hydrology, Upscaling, fractured media, flow, solute transport, thermo-hydro-mechanical processes, hybrid approach, continuum approximation, discrete fracture network, stochastic continuum, Hydrologi
National Category
Oceanography, Hydrology, Water Resources
urn:nbn:se:uu:diva-5739 (URN)91-554-6208-1 (ISBN)
Public defence
2005-04-29, Hambergsalen, Geocentrum, Villavägen 16, Uppsala, 10:00
Available from: 2005-03-31 Created: 2005-03-31Bibliographically approved

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