دیکشنری تخصصی مهندسی نفت - نسخه آنلاین

n: the common name for anhydrous calcium sulphate. caSﾰ4.

n: The main component is calcium sulphate which has no crystal water. The formation which contains this gypse is very usual in drilling and it can contaminate the fresh water drilling fluid. This formation swells when the drilling fluid go through it and som

CaSO4 formation. Usually formed as an evaporite from a drying lake of trapped sea water.

n: dissolved calcium ions in sufficient concentration to impart undesirable properties, such as flocculation, reduction in yield of bentonite, and increased fluid loss, in a drilling fluid. See also anhydrite, calcium carbonate, calcium sulphate, gypsum, lime.

n: The process that calcium ion enters into the drilling fluid when drilling in the calcareous formation or cement plug.

n: a chemical compound of calcium, sulphur, and oxygen, CaSﾰ4. Although sometimes considered a contaminant of drilling fluids, it may at times be added to them to produce certain proper- ties. Like calcium carbonate it forms scales in waterhandling facilities, which may be hard to remove. See anhydrite, gypsum.

n: a freshwater drilling mud using calcium oxide (lime) or calcium sulphate (gypsum) to retard the hydrating qualities of shale and clay formations, thus facilitating drilling. Calcium-treated muds resist salt and anhydrite contamination but may require further treatment to prevent gelation (solidification) under the high temperatures of deep wells.

n: a naturally occurring crystalline fom1 of calcium sulphate in which each molecule of calcium sulphate is combined with two molecules of water. See anhydrite. calcium sulphate.

n: a naturally occuring crystalline form of hydrous calcium sulfate.

n: a substance. such as salt. potassium chloride. or calcium sulphate. added to drilling mud to minimise the hydration (swelling) of formations with which the mud is in contact.