Investigation of Salt Precipitation in Geothermal Reservoir Near Sealing Conditions

Abstract

The main goal of the work is to investigate the behavior of a geothermal reservoir containing salty water when its physical parameters exceed the critical values, i.e. when the vaporization process cannot be described by the asymptotic self-similarity solution. We consider a low-permeability rock, where salty water vaporizes at a sharp front, because of fluid extraction at constant pressure. If the parameters are below the critical values the analytical results are in good agreement with results of 1D numerical simulations carried out by the TOUGH2-EWASG code. In these cases the numerical solution reaches a quasi-stationary regime, describing by the similarity solution. For a higher mass flux towards the well bore, when the critical parameters exceed the critical values, the numerical solution maintains a non-stationary regime until the porous space at the vaporization front is fully clogged (sealed) with solid salt.