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Communication Dans Un Congrès Année : 2008

A discrete dual-porosity fracture network for modeling flow in heterogeneous porous fractured media

Jean-Raynald de Dreuzy
Philippe Davy

Résumé

One of the main challenges of flow modeling in porous fractured media consists in accounting for the broad range of heterogeneities coming both from the existence of fractures at all scales and from the differences between fractures and the surrounding matrix. The broad-range fracture characteristics and the fracture/matrix duality have led to two different modeling paradigms, which are respectively the Discrete Fracture Network model (DFN) and the dual-porosity model. Existing modeling approaches rely either on the one or on the other. Our objective is to set up a new modeling framework accounting equally and consistently for both the fracture characteristic complexity and the fracture/matrix duality. We call it the discrete dual-porosity fracture network. Beyond the development of this model, we aim at understanding the influence of the fracture network structure on the exchange between fracture and matrix at block scale. The critical flow localization recurrently observed in fractured media is likely to be of major importance for the quantity of flow exchanged between fracture and matrix and for the transport of solutes potentially diffusing in the matrix. Practically, our model consists of a superposition of two overlapping media. The "fracture" medium consists of the major fractures represented as discrete features like in the classical Discrete Fracture Network approach. The "matrix" medium includes all other fractures of less influence to the main flow structure and the non-fractured surrounding porous medium. This method leads to a substantial simplification of the fracture network while retaining the observed flow channeling in some fractures. However, it requires some kind of inclusion of the less important fractures in the "matrix" medium. To this end, we develop a new operational homogenization method, the "Equivalent Hydraulic Matrix" (EHM), based on the linear relation between head and flow and designed to keep the salient structure of the less important fractures. We present the results of this method and the perspectives of this ongoing PhD.

Domaines

Hydrologie
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Dates et versions

insu-00377163 , version 1 (21-04-2009)

Identifiants

  • HAL Id : insu-00377163 , version 1

Citer

Jean-Raynald de Dreuzy, Philippe Davy. A discrete dual-porosity fracture network for modeling flow in heterogeneous porous fractured media. Gordon conference on flow and transport in permeable media, Jul 2008, Magdalen College, Oxford, United Kingdom. ⟨insu-00377163⟩
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