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...

Spudding In Denotes the start of the well. The term originated from cable tool drilling where spudding is the act of hoisting the drill pipe and letting it fall freely so that the drill bit...

Stable Isotopes Refers to non-radioactive isotopes of elements, including those of oxygen, hydrogen, carbon, sulfur, and nitrogen. In geothermal geochemistry, the stable isotope ratios of...

Steaming Ground Hot thermal ground associated with diffuse steam discharge. Vegetation is typically stunted or non-existent.

Steam-heated water A shallow formed water resulting from condensation of steam into groundwater accompanied by absorption of carbon dioxide to form a bicarbonate water or by absorption of...

Stimulation an operation carried out on a well that increases production or injection by improving the flow characteristics of the reservoir and enhancing the flow between the reservoir and...

Stored Heat Calculated thermal energy stored in a volume of hot rock. It is calculated using the rock volume, porosity, rock density, specific heat of rock, and the difference between the...

Tephra Airborne particles of rock and ash produced by an explosive volcanic eruption. Tephra commonly deposits as a blanket that drapes over the underlying topography.

THMC Acronym that stands for thermal, hydrological, mechanical, and chemical effects that is evaluated simultaneously when running numerical simulations of reservoir behavior during...

Transcurrent Fault (Strike-Slip Fault) Vertically dipping fault that results from horizontal shear stress. Slip movement during an earthquake is sideways rather than up or down.

Two-Phase Flow A condition that is attained in production wells associated with high temperature (>200°C) geothermal reservoirs, wherein the flowing fluid comprises a mixture of steam...

Turbine Spinning axle mounted with fan blades that converts a fluid flow stream into mechanical energy. To produce electricity, the mechanical energy from the turbine is connected to a...