Physical Characterization of Rocks in Thung Nui Hot Spring, Satun Province, the South of Thailand

摘要

In this study, Physical properties of rocks from geothermal reservoir were investigated. To describe rock properties of the selected outcrops, density, radioactivity, and heat production were researched. The obtained density of granite rock from Triassic period and limestone rock from Ordovician period were 2,648±112 kg/m~3 and 2,637±96 kg/m~3, respectively. Radioactivity of ~(226)Ra ~(232)Th and ~(40)K of granite rock were measured as 109.9±17.2 Bq/kg, 134.2±9.5 Bq/kg, and 1,569.3±75.7 Bq/kg, respectively. For limestone rock, it shows 13.8±6.4 Bq/kg, 23.3±7.7 Bq/kg, and 394.1±117.8 Bq/kg, respectively. After grinding the samples, radioactivity values of ~(226)Ra, ~(232)Th, and ~(40)K were measured by gamma spectrometer. It was found that the concentration of ~(238)U, ~(232)Th, and ~(40)K in granite rocks from Triassic period were 8.90 ppm, 33.07 ppm, and 5.06%, and limestone rocks from Ordovician period are 1.11 ppm, 5.73 ppm, and 1.27%, respectively. The physical properties of reservoir rocks giving geological parameter information were necessary to understand geothermal system of the area in this study and to develop renewable energy for the community.