Word of the Week – Steaming Ground
Steaming Ground Hot thermal ground associated with diffuse steam discharge. Vegetation is typically stunted or non-existent. Read More »Word of the Week – Aquifer
Aquifer Porous and permeable rock unit or unconsolidated layer in the subsurface in which all the pores and voids are filled with water. Water supply for wells comes from aquifers. Read More »Word of the Week – Epidote
Epidote Alumino-silicate hydrothermal mineral having a distinctive yellow-green color that is used a mineral geothermometer, forming at temperatures above ~230°C. The first down hole occurrence of epidote commonly coincides with the top of a high-temperature geothermal reservoir where it is hosted by igneous rocks. Read More »Word of the Week – Illite
Illite A potassium-bearing mica-like clay mineral that is a product of hydrothermal alteration. It commonly replaces feldspars and other alumino-silicate minerals and it forms above ~220°C. It also reflects a weakly acidic pH condition in hydrothermal fluids. Read More »Word of the Week – Propylitic Alteration
Propylitic Alteration A term borrowed from studies of hydrothermal ore deposits that refers to an assemblage of secondary hydrothermal minerals which forms in igneous rocks. This assemblage is made up of chlorite, illite, feldspar (both Na and K-rich varieties), epidote, calcite and pyrite, imparting a dark green tint to the appearance of altered rocks. It… Read More »Word of the Week – Mineral Geothermometer
Mineral Geothermometer A secondary mineral phase whose stability is defined by a lower and sometimes an upper temperature threshold. Common mineral geothermometers comprise clays, zeolites and epidote, with crystal structures that contain a hydroxyl (OH-) or water (H2O) molecule. The temperature ranges of mineral geothermometers are calibrated from investigations of a large number of drilled… Read More »Did you know… 20% of the Island of Hawai’i’s power comes from geothermal energy?
Did you know... 20% of the Island of Hawai'i's power comes from geothermal energy? Located in Puna (Kilauea East Rift Zone), is Hawai’i’s geothermal power plant, Puna Geothermal Venture (PGV). PGV has two air-cooled power plants, a binary system, and a combined cycle system. The plants together generate up to 38 megawatts of electricity. The first… Read More »At the Core 9th Edition (April 2022)
Keep up to date on what is going on at Utah FORGE. Read about it in the quarterly newsletter. SUBSCRIBE and receive updates and special announcements. Open and download a pdf version at-the-core-april-2022. Read More »Word of the Week – Slotted Linear
Slotted Liner In geothermal wells, this is a type of production casing that does not go to the surface, and instead with the aid of a “liner hanger” it extends below the casing shoe to protect the wall of the well. Slotted liner has pre-milled slots that allows for production or injection of fluids along… Read More »Geothermal Song Parody Contest Winners
Utah FORGE and Enel-sponsored Geothermal Music Parody Contest Read More »Word of the Week – Casing Shoe
Casing Shoe In geothermal wells, this is the bottom of the cemented casing string. Below the casing shoe, the well may be unprotected and open to the surrounding rock or lined with a slotted liner. The depth of the casing shoe generally coincides with the top of the production interval in the reservoir. Read More »Word of the Week – Peak Load Generation
Peak Load Generation The amount of power required to maintain an electric grid for short-lived periods (e.g., morning, late afternoon and evening) in response to high demand. Thermal power plants that burn natural gas and hydroelectric dams are two common modes of peak load generation. Read More »Word of the Week – Normal Fault
Normal Fault Refers to a steeply dipping planar fault in which the upper block slides downward relative to the lower block. Such fault movement is characteristic of extension and extensional tectonic regimes like the Basin and Range province of the western USA. Read More »Word of the Week – Dolomite
Dolomite A carbonate mineral similar to calcite in which magnesium partially substitutes for calcium. Read More »Word of the Week – Felsic
Felsic A geological term referring to igneous rocks that are equivalent to rhyolite and granite in composition. Read More »Did you know… one of the world’s largest hot springs is in New Zealand?
Did you know... one of the world’s largest hot springs is in New Zealand? Located in the Waimangu Volcanic Rift Valley near Rotorua, Frying Pan Lake is one of the world’s largest hot springs! It is also one of the youngest, with a precise birthdate of April 3, 1917, having filled and formed in the… Read More »Word of the Week – Mafic
Mafic A geological term referring to igneous rocks that are equivalent to basalt and diorite in composition. Read More »Word of the Week – MWD
MWD Refers to Measurement While Drilling which for directional drilling includes geospatial information that is used to steer the bottom hole assembly (BHA). Inclination and azimuth are surveyed using accelerometers and magnetometers which are incorporated into MWD tools. Other MWD information includes rotational speed of the drill string, type and severity of downhole vibration, temperature,… Read More »Word of the Week – BHA
BHA Refers to Bottom Hole Assembly, which is the system of tools at the bottom of the drill string that is used for drilling directional wells. The BHA includes the drill bit, mud motor, drill collar, and any tools that are used for making measurements while drilling. Read More »Word of the Week –
Heat exchanger A device or engineered system that is used to transfer thermal energy in soil, rock or produced fluid to heat a closed loop through which another fluid is circulated. Heat exchangers are used in ground sourced heat pumps, binary plants, and a range of direct use applications. Read More »
