دیکشنری تخصصی مهندسی نفت - نسخه آنلاین

n: the force in dynes that a stationary flat plate with a surface area of 1 square centimetre exerts on a similar parallel plate 1 centimetre away and moving in its own plane with a velocity of 1 centimetre per second, the space between the plates being filled with the liquid in question. It is a measure of the resistance that the liquid offers to shear. absolute error n: the difference between the result of a measurement and the true value of the measured quantity as determined by means of a suitable standard device.

n: The pressure within a system caused by fluid friction or an induced resistance to flow through the system. Hydraulic Thru-Tubing Fishing tools are typically operated using back pressure created by fiow through a nozzle.

a pressure caused by a restriction or fluid head that exerts an opposing pressure to flow.

n: on a roller cone bit, a coneshaped steel device from which the manufacturer either mills or forges steel teeth, or into which the manufacturer inserts tungsten carbide buttons. Most roller cone bits have three cones, which roll, or rotate, on bearings as the bit rotates. As the cones roll over the formation, the cutters on the cone scrape or gouge the formation to remove the rock.

n: a drilling bit with tungsten carbide inserts on the cones that resemble plugs or buttons. See roller cone bit.

nn: The cone bit which is installed with obtuse tungsten carbide insert.

n: the amount of pressure that, when applied inside a string of casing, causes the wall of the casing to fail. This pressure is critically important when a gas kick is being circulated out, because gas on the way to the surface expands and exerts more pressure than it exerted at the bottom of the well.

n: The pressure leading to collapsing of the casing.

n pi: (slang) certifications of materials on physical and chemistry properties.

certificates, usually on physical or chemical properties (e.g., MSDS Sheets).

n: that part of the cone of a Toner cone bit out of which the teeth are milled or into which tungsten carbide inserts are placed and inside of which the bearings are housed.

n: The shell of cone bit.

v: to carry on drilling operations with a mud whose density is such that it exerts less pressure on bottom than the pressure in the fonnation while maintaining a seal (usually with a rotating head) to prevent the well fluids from blowing out under the rig. Drilling under pressure is ad- vantageous in that the rate of penetration is relatively fast;however, the technique requires extreme caution.

n: (ERTS) see Landsat.

abbr: Earth Resource Technology Satellite.