1990 年 12 巻 3 号 p. 229-237
Four hot spring areas, located at Ban Nam Ron, Ban Pu Toei, Ban Pu Kham and Ban Wang Kham, are to be found in Phetchabun province, approximately 350km northeast of Bangkok, Thailand. The surface temperatures range from 35 to 47°C; the discharges are generally small. Systematic studies were carried out to select for further exploration drilling the geothermal energy system showing the highest potential. These studies included geologic, geophysic (resistivity) and geochemical work. The geological work included field mapping, petrographic studies and fracture analysis, as well as the compilation of a 1:15, 000 geologic map and cross-section. Schlumberger profiling and depth sounding resistivity surveys, covering a distance of 105km, were carried out and the results are shown in isoresistivity contour maps. Water samples, in the form of both groundwater and hot spring water, were collected and analysed. The Phetchabun geothermal system is principally a fracture-controlled system and is classified as a low-enthalpy system with subsurface temperatures of around 120°C. The potential uses are therefore restriced to direct uses. The Pu Kham hot spring, the most easily accessible, densely populated, and with agricultural products easy available, is considered to be the most viable for exploration drilling to a proposed maximum depth of 100m. The proposed exploration well should encounter hot water upflowing along fracture zones at a depth of not more than 100m. The potential uses will depend on the temperature and quantity of the hot water flow (discharge). This work is part of a contracted research project supported by a grant from the National Energy Administration (NEA) of Thailand.
