Modélisation du comportement hydrogéomécanique d’un réseau de failles sous l’effet des variations de l’état de contrainte

Abstract : In the present work, we address the issue of groundwater flow in the fractured porous media submitted to local or regional stress-state variations. Due to the increasing pore fluid pressure, the length and aperture distribution of the fractures are modified resulting in the formation of preferential flow channels within the geological formation. The numerical approach proposed is a fully coupled hydro-poro-mechanical model in saturated conditions involving single-phase flow both in fractures and in the porous matrix. The extended finite element method (XFEM) is employed for modeling fracture dynamics and flow calculation for fracture which do not lie on the mesh but cross through the elements. In this study: (i) we consider the pressure build up generated by fluid flow inside and through the fracture, (ii) the fracture dynamics by using a cohesive zone model (CZM) on pre-existing propagation path and (iii) fluid exchanges may occur in between fractures and porous medium. The last specification of the HM-XFEM model is taken into account through the introduction of a Lagrange multiplier field along the fracture path. These fields are the result of the dualised condition of pressure continuity between the pore pressure and the fluid pressure inside the fracture. As a function of the Lagrange multiplier value, both permeable and impervious fractures can be considered. The cohesive law employed is a non-regularized-type cohesive law to ensure propagation and eventually closure of the fracture. Validation of the model has been conducted by means of the well-known KGD fracture model when different propagation regimes are considered. We applied the HM-XFEM model to the case of multi-stage fracture network stimulated by the injection of incompressible fluid at constant rate. Fractures are not connected to each other and evolve on pre-existing propagation paths. We aim at appreciating the influence of the fluid viscosity, the injection rate and spacing between each fracture, on the fracture propagation. A peculiar attention is paid to the stress-shadowing effect (i.e. interaction between fractures).
Complete list of metadatas

https://hal.univ-lorraine.fr/tel-01752354
Contributor : Thèses Ul <>
Submitted on : Thursday, March 29, 2018 - 1:42:58 PM
Last modification on : Friday, April 5, 2019 - 8:21:42 PM

File

DDOC_T_2016_0080_FAIVRE.pdf
Files produced by the author(s)

Identifiers

  • HAL Id : tel-01752354, version 1

Citation

Maxime Faivre. Modélisation du comportement hydrogéomécanique d’un réseau de failles sous l’effet des variations de l’état de contrainte. Autre. Université de Lorraine, 2016. Français. ⟨NNT : 2016LORR0080⟩. ⟨tel-01752354⟩

Share

Metrics

Record views

110

Files downloads

105