Geothermal Silica Saturation Index (SSI) Calculator
Determine amorphous silica solubility, Silica Saturation Index (SSI), and safe minimum reinjection temperature to prevent wellbore pipeline scaling.
Brine Chemistry & Cooldown
Saturation Index & Scaling Risk
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Frequently Asked Questions
What is the Silica Saturation Index (SSI) in geothermal systems?
SSI is the ratio of dissolved silica concentration to the equilibrium thermodynamic solubility of amorphous silica at a given temperature. When SSI exceeds 1.0, the brine becomes supersaturated.
Why is silica scaling the universal bottleneck for geothermal energy extraction?
Geothermal fluids dissolve massive amounts of quartz at reservoir conditions (>250°C). As heat is extracted and steam is flashed off, the brine cools and concentrates, driving silica into extreme supersaturation (SSI > 1.3) where it polymerizes into amorphous glass scale.
How do operators prevent silica scale in reinjection wells?
Operators maintain reinjection temperature above the SSI = 1.0 threshold (e.g., 140°C–160°C), inject acid to lower pH to ~5.0 (which retards polymerization kinetics), or employ silica crystallization-clarification seed plants.