Kohei Akaku

Geochemical study on mineral precipitation from geothermal waters at the fushime field, Kyushu, Japan

Abstract The fluids in the Fushime geothermal system, Kyushu, Japan, are hot and saline, and most likely originate from seawater-rock interaction. The type of scale precipitated from the waters differs according to its location in the flow test facilities. Galena and sphalerite are commonly the predominant minerals in the scale coating the insides of the two-phase lines and amorphous silica tends to be dominant in the sections further downstream. Anhydrite has been found to precipitate in a specific zone of a production well where relatively cool sulfate-rich water is believed to mix with ascending hot sulfate-depleted water.