Before it became the world’s largest geothermal power-producing site, The Geysers was known as the “Gates to Hades,” drawing visitors with its healing waters, steam vents, and wild legends.
Drill Core
Intact cylindrical shaped sample of rock obtained during drilling with a special coring bit. Although commonly narrow in diameter (e.g., 1-4″ or 25-100 mm), it preserves a geological record that makes it possible to interpret the sequence of mineral formation, fracturing, and vein filling.
Geothermal Glossary
Word of the Week – Cement Bond Log
Cement Bond Log A geophysical well log that is obtained using a sonic-type tool on a wireline. The result helps to confirm the integrity of the hardened cement that was injected to form a bond between well casing and the adjacent rock formation.
Word of the Week – Chemical Geothermometer
Chemical Geothermometer A temperature that is calculated based on the chemical composition of a hydrothermal fluid and involves knowing a ratio (e.g., Na/K) or knowing the absolute concentration of a species (e.g., SiO2). Temperature is computed using a simple...
Word of the Week – Chlorite
Chlorite A micaceous mineral that is commonly green-colored, composed of iron and/or magnesium, and forms due to hydrothermal alteration of amphiboles, pyroxenes, and feldspars.