Simulation Model of Silica Scale in Geothermal Wells: Case Study

Abstract

Silica deposition in geothermal wells is one of the causes of the decline in geothermal production. Fluid from the seservoir that has been saturated by silica flows in the wellbore and begins to become two phases. This scale deposition occurs due to the flashing process in geothermal wells where hot water turns phase into steam in the wellbore. silica deposition occurs in several wells. From the results of the geochemical analysis of R-5 wells in May 2014, the SiO2 concentration of production fluid was 639.36 ppm, Cl concentration of 16875 ppm, and silica saturated index (SSI) of the R-5 well reached 1.78. Silica deposition can occur because of the reboiling and condensation processes as well as the flashing process. Pressure and temperature data from running PTS only present qualitative data from the fluid phase and do not present complete quantitative data from the fluid regime. Therefore, to determine flow regime and the rate of deposition of the scale, the CMG-Stars software is used.