Calcium transport during circulation in Hot Dry Rock system
Calcium transport was estimated in the Hijiori Hot Dry Rock geothermal system. During circulation test, we collected scale samples: calcite and aragonite at the pipeline and anhydrite at the deep production well. After a 3-month circulation test, we measured the thickness of calcite scale on the pipeline of HDR-2. The～50 mm thickness means that about 2.7 tonnes of calcite (1.04 tonnes calcium) precipitated. Also we estimated anhydrite dissolution volume from the fluid chemistry at the injection and production wells. Anhydrite dissolved near the injection well by cool water but then Ca re-precipitated as anhydrite in the reservoir with temperature increase. After anhydrite precipitation, calcite precipitated in the surface pipeline and in the shallow well. After 3 months, 7.5 tonnes Ca was contained in the circulation fluid, and 2.7 tonnes Ca was contained in calcite scale in the surface pipeline and shallow production well.
N.Yanagisawa I.Matsunaga H.Sugita N.Tsuchiya
National Institute of Advanced Industrial Science and Technology, Tsukuba, Japan Graduate School of Environmental Studies of Tohoku UniversitY, Sendai, Japan
国际会议
第十二届水-岩相互作用国际研讨会(P0roceedings of the 12th International Symposium on Water-Rock Interaction)
昆明
英文
259-262
2007-07-31（万方平台首次上网日期，不代表论文的发表时间）