Environmental Engineering Reference
In-Depth Information
wells MS-5 and NB-3) and from 25 to 85, respectively, while patterns (c) and (d) have
activity indices from 61 to 98 and from 77 to 90, respectively. Patterns (b), (c) and (d) of
convection type belong mainly to Types A or B. The proposed field of geothermal power
plant construction, where is necessary to have a reservoir temperature above 180
℃
, shows
patterns does not belong to pattern (a).
Figure 6. Activity index of each exploration well drilled in the “Geothermal Development Promotion
Survey” fields by NEDO. A symbol shows a maximum recovery temperature within the depths where
Th values were measured in a well.
3. GAS Chemistry
3.1. Crushing Experiments
The semi-quantitative gas analytical method using a crushing stage was devised by
Sasada et al. (1986). When a transparent mineral was crushed using the stage under the
microscope (Roedder,1970), behavior of vapor bubble in individual liquid-rich inclusion
related to the internal pressure of the non-condensable gases gives semi-quantitative
information on gas content in the inclusion. As CO
2
is a major component of the non-
condensable gases in most geothermal fields (Ellis and Mahon, 1977), Sasada et al. (1986)
assumed a simplified model in which all the non-condensable gas is CO
2
in a liquid-rich
inclusion. The convenient and cost-effective method can be used to low saline liquid-rich
inclusion frequently found in geothermal environment. The crushing experimental results
were previously performed on transparent minerals from the four geothermal fields in Japan,
containing Hohi (Sasada et al., 1986), Kakkonda (Muramatsu et al., 1996), Kirishima (Sawaki
et al., 1997) and Matsukawa (Muramatsu et al., 2006).
For example, the crushing experimental results for the Matsukawa and Kakkonda
geothermal fields are shown in table 2. The experiment was conducted on hydrothermal
anhydrite collected from 916 m depth of well M-11 in Matsukawa. The collapse of vapor
Search WWH ::
Custom Search