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 is commonly developed in volcanic-plutonic sequences that host high-temperature geothermal reservoirs.

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Word of the Week – Cyclone Separator

Word of the Week – Cyclone Separator

Cyclone Separator A large cylindrical vessel attached to two-phase production pipelines in geothermal fields that is used to separate dry steam from a fast-moving two-phase fluid. Steam...

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Word of the Week – DAS

Word of the Week – DAS

DAS Distributed Acoustic Sensor. Involves the deployment of fiber optic cable on the surface or in a well, and the detection of small variations in the refractive index of the fiber based...

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Word of the Week – DFIT

Word of the Week – DFIT

DFIT Diagnostic Fracture Injection Test. A subsurface well test in which pressure is monitored as a small volume of fluid is injected into a reservoir to develop a hydraulic fracture....

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