Caractérisation par micro-sismicité induite des propriétés des massifs poreux fracturés. Modélisations par la méthode des lignes de courant d'un site géothermique HDR (Soultz-sous-Forêts, France)

Institut National Polytechnique de Lorraine

Abstract

At Soultz-sous-Forets (Alsace, France), a European research project investigates technical and ˆ technological solutions to extract the heat contained in the upper part of the continental crust. The aim of this project is to circulate cold water at depth, warm it during circulation, extract the heat contained in the pumped fluid and reinject it. The feasibility of this HDR concept is still to be proven. To estimate the life time of such an exchanger, numerical modelling is required. The streamline technique which is already widely used in petroleum reservoir modelling was applied to compute fluid flow, tracer transfer and thermal evolution problems inside geothermal reservoirs. To do such kind of modelling, the permeability field inside the reservoir is required. It was estimated using a new SBRC-based inversion method which uses the induced microseismic clouds recorded during hydrofracturing experiments as a marker of the fracturation front position. This new methodology allows to quantify the heterogeneous isotrope permeability and allows to quantify its increase during the fracturation tests. The numerical solvers developed during this work were finally used to simulate the behavior of the Soultz-sous-Forets geothermal exchanger and to demonstrate the ability of the new SBRC- ˆ based methodology to estimate the reservoir permeability.

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BibTeX Reference

@PHDTHESIS{Voillemont2003,
    author = { Voillemont, Jean-Charles },
     title = { Caractérisation par micro-sismicité induite des propriétés des massifs poreux fracturés. Modélisations par la méthode des lignes de courant d'un site géothermique HDR (Soultz-sous-Forêts, France) },
      year = { 2003 },
    school = { Institut National Polytechnique de Lorraine },
  abstract = { At Soultz-sous-Forets (Alsace, France), a European research project investigates technical and ˆ
technological solutions to extract the heat contained in the upper part of the continental crust. The
aim of this project is to circulate cold water at depth, warm it during circulation, extract the heat
contained in the pumped fluid and reinject it. The feasibility of this HDR concept is still to be
proven.
To estimate the life time of such an exchanger, numerical modelling is required. The streamline
technique which is already widely used in petroleum reservoir modelling was applied to compute
fluid flow, tracer transfer and thermal evolution problems inside geothermal reservoirs.
To do such kind of modelling, the permeability field inside the reservoir is required. It was estimated
using a new SBRC-based inversion method which uses the induced microseismic clouds
recorded during hydrofracturing experiments as a marker of the fracturation front position. This
new methodology allows to quantify the heterogeneous isotrope permeability and allows to quantify
its increase during the fracturation tests.
The numerical solvers developed during this work were finally used to simulate the behavior
of the Soultz-sous-Forets geothermal exchanger and to demonstrate the ability of the new SBRC- ˆ
based methodology to estimate the reservoir permeability. }
}