| Title | Investigations on Hydrothermal Activities Using Fluid Inclusion Geothermometry in the Otake and Hatchobaru Geothermal Fields |
|---|---|
| Authors | Takagi, H., Fujino, T., Kurokawa, K., |
| Year | 1988 |
| Conference | Japan International Geothermal Symposium |
| Keywords | |
| Abstract | The homogenization temperatures of fluid inclusions in hydrothermal minerals such as quartz, anhydrite and calcite from wells in the Otake and Hatchobaru geothermal fields have been measured. The fluid inclusion temperatures from wells drilled in the producing zone distribute along a narrow range a little inside of the boiling point curve. The lowest value of the fluid inclusion temperatures at each depth is quite close to the present temperature of fluid conduits and reservoirs. The reservoir temperature in the Otake geothermal field is estimated to be 190 -200°C at the producing level (300 -500 m below surface) and 250 -280°C at the producing level (1,000 1.500 m below surface) in the Hatchobaru geothermal field. The distribution of fluid inclusion temperatures from wells drilled in the reinjecting zone has a wide range and show a bimodal distribution. The lowest value of the low temperature peak agrees well with the present temperature. whereas the value of the higher temperature peak appears to be equal to the original reservoir temperature. The temperature contour map at the producing level in the Otake geothermal field obtained from the fluid inclusion geothermometry shows that the geothermal fluid comes up from the south at a steep angle and forms a reservoir with temperature of 190 -220°C. In the Hatchobaru geothermal field, the temperature contour map reveals that a high temperature zone above 270°C strikes east to west and breaks towards the north at southeast of the power plant. |