ESTIMASI SUHU RESERVOIR SUMBER MATA AIR PANAS HATUASA AMBON DENGAN METODE GEOKIMIA BERDASARKAN PENGEMBANGAN PERSAMAAN GEOTERMOMETER EMPIRIS; RESERVOIR TEMPERATURE ESTIMATION USING GEOCHEMISTRY METHOD BASED ON DEVELOPED EMPIRICAL GEOTERMOMETRY EQUATION IN THE HATUASA HOT SPRING, AMBON

Helda Andayany, Sismanto

2010 | Disertasi | PROGRAM STUDI S2 ILMU FISIKA

The research compares several existing empirical geothermometry equations to new developed geothermometry equations that have been successfully formulated by comparing the parameters of root mean square error (rms errors) and identifying the hot flow character, as well as reservoir temperature of Hatuasa hot spring, thus the prospects of certain geothermal field in research area can be determined. Geochemistry method employed in the research, based on developed empirical geothermometry equation which involves chemical elements, was obtained from the result of chemical analysis of hot water sample with Atomic Absorption Spectrophotometer method (AAS-NYALA). The result of chemical analysis of Hatuasa hot water sample, which are in the forms of concentration of Na, K, Calcium, Magnesium, and SiO2 are then inserted into the best assumed geothermometry formulas to be applied in Hatuasa. The temperature measured by using the aforementioned geotermometry formulas possesses rms error value < 2 % which is enabled as Hatuasa reservoir temperature. The result of measurement of water surface temperature, pH, and electrical conductivity in the Hatuasa hot spring site on 31 August to 1 Septembers 2010, it is indicated that Hatuasa geothermal tipe is a geothermal tipe with high temperature, i.e.: (272 – 277)oC that is potential for a geothermal field. The hot flow character in Hatuasa geothermal tipe is water flow into the upper reservoir (upflow) and belongs to hot water domination reservoir tipe (water heated reservoir). Besides, based on the calculation of reservoir temperature at four measurement points in Hatuasa hot spring, a linear relationship with surface temperature, pH and electrical conductivity is obtained. This means that the higher the surface temperature and electrical conductivity measured, the higher the temperature of Hatuasa reservoir and the contrary, the lower the pH measured.

Kata Kunci : persamaan geotermometer, suhu reservoir, upflow, reservoir dominasi air panas