FLUID-MINERAL EQUILIBRIA AND INJECTION IN EGS — EFFECT OF INJECTING GROUNDWATER

Mineralization from groundwater injection augmentation in the Coso geothermal system was simulated to assess possible effects on the Coso-EGS injection well 34-9RD2. Anhydrite + dolomite or anhydrite + calcite dominate when the waters are conductively heated, while mixing produces these minerals plus a magnesium silicate. The quantities and relative proportions of the minerals are dependent on the relative rates of heating and mixing. The results of this study will be used in our ongoing petrographic and x-ray studies of injection-induced mineralization in existing wells.