We conducted tracer experiments using a two-dimensional porous medium modeling a vertical fault system. The medium has a dimension of 600mm long, 1500mm wide and 20mm thick, and was filled with glass beads of 1mm diameter. In order to visually observe the tracer movement in the model, we injected dyes as tracer materials. We developed an optical tracer concentration sensor for concentration measurement on the basis of absorption spectrophotometry method. The sensor was located at the outlet of simulated production well. Simultaneous injection of different tracer dyes at two reinjection wells was conducted and concentrations of each tracer were successfully measured at the production well with this newly developed sensor.
Binary power generation test using about 97 °C hot spring fluid is progressing at the Matsunoyama geopressured hot spring field in Niigata Prefecture characterized by about 9,000 mg/l Cl and high methane concentration. At Matsunoyama, the geochemical monitoring was carried out at Takanoyu#3 well used for the binary system and the surrounding hot spring wells from October 2010. The flow rate of Well-3 was almost constant in spite of the change of flow rate used for binary test of Takanoyu#3 well. The coefficients of variation of pH, EC, temperature and chemical concentrations were from 0.01 to 0.06 until February 2014. But the coefficients of variation of HCO3 concentration, Si concentration at Takanoyu#3 and Ca concentration at Well-3 were more than 0.1. The main reason of variation was the Nagano North Earthquake (2011) occurred at 12 March, 2011 near Matsunoyama hot spring field. At Well-3, the Ca concentration increased from 100 to 200 mg/l and the HCO3 concentration decreased from 320 to 240 mg/l at the time of this earthquake. At Well-1, Na and Cl concentrations were stable during 70 years.
In Indonesia, the Governmental Law specifies that the government is responsible for data collection concerning geothermal resources to mitigate the risks often occurring at an initial stage of geothermal development. This task lies on the Center for Geological Resources (CGR) under the Ministry of Energy and Mineral Resource (MEMR), which assumes a heavy responsibility. In response to the request from the Government of Indonesia (GOI), a capacity development project of the Japan International Cooperation Agency (JICA) and MEMR was formulated in order to reinforce CGR’s capability in geothermal resource survey, exploration and evaluation. The project had been conducted for three years since October 2010 to September 2013. The project activities were successfully carried out by combining the learning process of CGR from JICA experts with their self-trials and teaching processes at workshops. The technology transfer was carried out by improving the CGR’s abilities of field surveys and analyses together with introduction of new measurement equipment and software.