calcium transpot by water-rock interaction in geothermal system

Abstract

Calcium transport was estimated in the Hijiori Hot Dry Rock geothermal system, Yamagata, Japan. During 3 month circulation test from Jun 2002 to Aug 2002, we collected and calculated mass of scale samples: calcite and aragonite at the pipeline of 2 wells and anhydrite at the deep production well. Also we estimated supplied calcium to production well from the fluid chemistry at the injection and production wells. Then 2.6 ton calcium was supplied from anhydrite of reservoir granite rock and 3.3 ton calcium precipitated as calcite or aragonite in production wells with fluid temperature and pressure decreasing.