دیکشنری تخصصی مهندسی نفت - نسخه آنلاین

estimation/measurement of age of a formation, fossil, etc., in years before the present.

n: (Ac) a white or gray midlevel cloud that appears as closely arranged rolls. This type of cloud is composed of either ice crystals or water droplets.

n: one type of misalignment in a chain-and-sprocket drive. The shafts are not parallel to each other (they form an angle) in either the horizontal or the vertical plane. This pulls the link plates on one side tighter than those on the other side;thus, one side of the chain and sprockets wears faster than the other. Link plates on only one side of the chain break because of fatigue.

n: the viscosity of a drilling fluid as measured with a directindicating, or rotational, viscometer.

n: The viscosity a fluid appears to have on a given instrument at a stated rate of shear. It is a function of the plastic viscosity and the yield point. The apparent viscosity in centipoises, as determined by the direct-indicating viscometer, is equal to the

the viscosity at a given shear rate and a given temperature.

an eon of geologic time extending from about 3.9 billion to 2.5 billion years ago.

(failure/crack development): characteristic markings (ridges, tears, risers, etc.) on fracture surfaces after fatigue crack of fracture propagation (also known as beach marks, clamshell marks, and conchoidal marks).

characteristic markings (ridges, tears, risers, etc.) on fracture surfaces after fatigue crack of fracture propagation (also known as clamshell marks, conchoidal marks and arrest marks).

n: a special well-control tool made up in the drill pipe usually just above bubble, of gas enter the annulus, the bubble chopper allows mud in the drill string to be diverted into the gas bubble by means of an opening, or port, in the tool. The mud from the drill string mixes with and spreads out the large gas bubble so that the gas cannot expand to a great extent as it nears the surface. Reducing the amount of bubble expansion reduces pressure on the casing near the surface and thus minimises the chances of formation fracture and an underground blowout.

a geological time from 500 million to 570 million years ago. Often signals the earliest hydrocarbon productive rocks.

n: a pipeline construction technique used in swamps and marshes. The first of several barges clears the right-of-way and digs a trench large enough to float itself and the following barges.