Salt precipitation in porous media and multi-valued solutions G. G. Tsypkin Institute for Problems in Mechanics RAS, Moscow, Russia

1
Salt precipitation in porous media and
multi-valued solutions G. G. TsypkinInstitute
for Problems in Mechanics RAS, Moscow, Russia

• Petroleum engineering gas hydrate, paraffin
  etc. formation
• Soil sciences salt precipitation, ice
  formation etc.
• Chemical engineering filters
• Geothermal reservoir engineering salt
  precipitation, crystallization of components due
  to chemical reactions etc.

2
Salt precipitation in soilswith destruction of
porous media
3
SPE 68953 The Precipitation of Salt in Gas
Producing WellsW. Kleinitz, SPE, M. Koehler and
G. Dietzsch, SPE, Preussag Energie GmbH, Germany.
2001.Scanning electron micrograph of
precipitate formation in the sample of rock
4
Sketch of the problem salt precipitation in
geothermal reservoirs
5
Basic equations
Vapor domain
Water domain
? porosity, ?? density, k permeability, µ
viscosity, ?w compressibility, h specific
enthalpy, e the specific internal energy, ?
thermal conductivity, T temperature, P
pressure, v filter velocity, Spr solid salt
saturation, c salt concentration
6
Boundary conditions through the interface
Discontinuities of water and salt saturation
functions
Mass balance for H2O and salt
Momentum balance
Thermodynamic equilibrium
Energy balance
Initial and boundary conditions
Similarity solution
7
Variation of the mass of salt in the vapour
domain as a function of reservoir pressure
Tsypkin G., Woods A. J. Fluid Mech. 2005
8
Analytic (1) and numerical results (2) Tsypkin
G., Calore C. Proc. 32nd Workshop on Geothermal
Reservoir Engineering, Stanford, 2007
9
Salt diffusion influence in low-permeability
reservoirsTsypkin G. Fluid Dynamics. 2009.
T const
10
Conclusions

• There are two self-similar solution branches for
  precipitation problem
• These two branches coincide for critical values
  of the parameters, and above these values, the
  self-similar solution ceases to exist
• For a higher initial pressure and larger well
  pressure rock becomes fully sealed with salt
• Salt diffusion may lead to a sleeping regime
  formation in low-permeability rock