Hydrogeology

Modelling flow and mass and energy transport in aquifers (contact : patrick.goblet(-at-)mines-paristech.fr)

The METIS code simulates the mechanisms of flow and mass and heat transport in porous media or fractured aquifers. Its main applications concern further areas (not exhaustive) :

  • Flow simulation in aquifer structures. Scales considered can range from the local level (flows in structures such as dike, dam, dump, ...) to the regional level (simulated of multilayer aquifer structures).
  • Simulation of contamination by soluble pollutants, possibly taking into account simple non-conservation mechanisms.
  • Simulation of resource exploitation in low enthalpy geothermal.
 

In one-dimensional, two-dimensional Cartesian or radial, and three-dimensional geometry, METIS takes into account further mechanisms :  

  • Flow in saturated or unsaturated environment. This mechanism is described by solving the equation of the diffusivity in steady or transitory regime.
  • Transport of a species in solution (tracer) by convection, diffusion, dispersion, radioactive decrease, relationship, linear instantaneous interaction. These mechanisms are described by the equation of the dispersion.
  • Dissemination from the main aquifer in impermeable blocks (matrix diffusion).
  • Heat transfer by convection, diffusion, dispersion (equation of the heat dispersion).
  • Dense coupling between flow and mass and/or heat transport.

 

The equations are solved by the finite element method. METIS uses DELOS mesh generator.

 

metis
 

 Representation of an unsaturated flow and  of the solute transport in a dam structure

 

MODCOU (contact : emmanuel.ledoux(-at-)mines-paristech.fr)

The MODCOU hydrogeological model couples surface and underground run-offs with the view to reproduce, among others, flows simulated at rivers and the piezometric levels of represented aquifers.

Globally speaking, a surface module gives the precipitation water balance (rain, snow) between evaporation, run-off and infiltration ; an underground module gives the transfer in aquifers and aquifer-river exchanges (Figure 1).

 

MODCOU 

Figure 1 : General principle of MODCOU coupled hydrogeological model

For this distributed model, the area studied is divided into a multilayer structure using nested square meshes the characteristics of the area are connected to :

  • drainage and run-off directions, elevation, distribution of production areas which are areas with similar characteristics in terms of precipitation water balance (distribution between runoff and aquifer recharge) for surface meshes, and
  • transmissivity, leakage, storage coefficient for underground layer meshes (Figure 2).

  

modcou2

 

Figure 2 : Principle of the multilayer schematization