Abstract: A method for reducing deposition of scale in geothermal wellbores and geothermal flash steam plants is described. Naturally occurring brines containing different amounts of dissolved solids and having contrasting chemical behavior are blended in controlled proportions to obtain improved properties in the mixture insofar as deposition of scale is concerned. The invention improves the usability of hypersaline brines, containing substantial quantities of sodium chloride, for power generation by blending them with cooler more dilute brines containing dissolved bicarbonate. By mixing the two brines within calculable limits of their proportions in the total produced fluid, deposition of sodium chloride and carbonate scales is avoided in the wellbore and in the downstream power generation equipment.

Abstract: A method for the treatment of geothermal brines to control the precipitation of silica is disclosed. A sulfate-rich liquid is introduced into geothermal brine within a production well prior to flashing or is introduced into the residual geothermal brine remaining after the brine has been flashed to produce steam. The sulfate in the liquid reacts with the barium, calcium, and/or lead salts within the brine to produce a colloidal suspension which serves to accelerate precipitation of silica from the brine and to adsorb the precipitated silica particles. The colloidal suspension with its adsorbed silica particles is then removed from the brine by conventional gravimetric or filtration methods.The method of the invention substantially reduces the deposition of silica in wellbores and in energy extraction equipment and facilitates removal of the silica from the brine. The method further reduces the deposition of silica in injection wells wherein the silica cleansed brine is discharged.