Preliminary Investigations of Scaling and Corrosion Characteristics of High Enthalpy Geothermal Wells in Hungary

Abstract

A solubility equilibrium program GEOPROF developed earlier was applied for the determination of the bubble point depth, pressure and temperature, plus the partial pressure profiles of the gases C02, C& and N2 between the bubble point depth and the well head, in two high enthalpy geothermal wells, NSZ-2 and FAB-4. In addition, the program also determined pH, alkalinity, total carbonate, equilibrium solubilities for CaCO,, CaSO,, BaSO,, SrSO, along the well depths in Na-K-Mg- Ca-H-Ba-Sr-C1-Br-S04-OH-HC03-C0,-C0,-H20 system. The concentrations of Ca2+, Ba2+, Sr2+, H+, OH-, HCOy, C032-, and H2C03* were computed at the actual temperature and CO, pressure, using the Davies and the Pitzer activity calculation methods. J'he calculated amounts of CaC03 scaling along the wells and at the surface were used to estimate and suggest a service life of the system. The results from well FAB-4 have high uncertainties because of the estimated gas separation analysis data.