The Matsukawa geothermal power station has been in commercial operation since 1966. Its geothermal reservoir was discovered by chance, by drilling of hot spring wells by the local administration in 1952. Japan Metals & Chemicals (JMC) noticed this phenomenon and started exploration for a geothermal power development in 1956. Then, JMC and Geological Survey of Japan (GSJ) started collaborative study in 1958. The biggest technical challenge for success in Matsukawa was a decision of drilling target depth for steam production and a casing shoe depth to stop in-flow of shallow cold water. It was examined through measurements of water levels in three exploration wells, borehole temperature profiles and flow rates of rivers. Geological and geophysical studies by GSJ helped this study. Owing to this study, the 1st production well succeeded to produce dry steam in 1964 and led to a success in the first commercial scale geothermal power development in Japan.
