| Title | Application of Fluid Inclusion Studies in Understanding the Thermal Systems in Shiramizugoe and Appi Geothermal Fields, Japan |
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| Authors | Yasuyuki Abe, Hiroyuki Ishizaki, Koichi Tagomori, Takamasa Horikoshi, and Tsuneo Kikuchi |
| Year | 2003 |
| Conference | PNOC-EDC Geothermal Conference |
| Keywords | |
| Abstract | New Energy and Industrial Technology Development Organization (NEDO) has studied fluid inclusion measurement technologies through the R&D theme of Modeling Support Techniques on the Development of Technology for Reservoir Mass and Heat Flow Characterization Project since 1997. As case studies, fluid inclusion measurement technologies were applied in Shiramizugoe in Kyushu and Appi in Tohoku, Japan. NEDO is currently implementing an exploration program under the Geothermal Development Promotion Survey Project in these two geothermal areas. In the Shiramizugoe area in southern Japan, drilling of five exploratory wells was completed. The lowest temperatures obtained from fluid inclusion analysis show good agreement with temperature profile from logging indicating that the combination of these two temperature data represent present subsurface thermal conditions. In the Appi area in northern Japan, four exploratory wells have been drilled while fifth well was spudded in August, 2002. Salinity was calculated on the basis of final melting point of ice and melting point of hydrohalite. These calculated values provide clues on the origin of geothermal fluids. In contrast to the Shiramizugoe area, the fluid inclusion data in Appi do not show good correlation with temperature profile based on the final equilibrium static temperature. Thus, formation temperature should be delineated mostly from temperature logging data. However, combination of fluid inclusion data and final static temperatures may be used in reconstructing the thermal history of the wells. |