دیکشنری تخصصی مهندسی نفت - نسخه آنلاین

n: A formation pressure that is higher than the normal formation fluid hydrostatic pressure.

n: pressure exceeding or falling below the pressure to be expected at a given depth. Normal pressure increases approximately 0.465 pow1ds per square inch per foot of depth or 10.5 kilopascals per metre of depth. Thus, normal pressure at 1,000 feet is 465 pounds per square inch;at 1,000 metres it is 10,500 kilopascals. See pressure gradient.

n: A formation pressure that deviates from the normal formation fluid hydrostatic pressure. Such pressure may be classified as "subnormal" (lower than normal) or "overpressured" (higher than normal).

n: a gas measurement device that consists of a mutiple-ported Pitot tube installed inside a pipe through which gas is flowing;it is installed perpendicular to the flow of gas. The length of the annubar is equal to the diameter of the pipe in which it is installed. An annubar senses the difference between total flowing pressure and static pressure;gas volume is calculated from this difference. See Pitot tube.

a gas flow rate measurement device using Pitot tubes. Common in pipelines.

n: 1. the pressure at the bottom of a borehole. It is caused by the hydrostatic pressure of the wellbore fluid and, sometimes, by any back-pressure held at the surface, as when the well is shut in with blowout preventers. When mud is being circulated, bottomhole pressure is the hydrostatic pressure plus the remaining circulating pressure required to move the mud up the annulus. 2. the pressure in a well at a point opposite the producing formation, as recorded by a bottomhole pressure bomb.

n: The pressure at the bottom of the borehole, or at a point opposite the production formation.

n: The surface pressure after well off. It is the static pressure bwtween casing and drill pipe or casing and reservoir. Reservoir pressure can be computed by casing head pressure.

n: a compressor in which the flow of gas to be compressed is moved away from the centre rapidly, usually by a series of blades or turbines. It is a continuous-flow compressor with a low pressure ratio and is used to transmit gas through a pipeline. Gas passing through the compressor contacts a rotating impeller, from which it is discharged into a diffuser, where its velocity is slowed and its kinetic energy changed to static pressure. Centrifugal compressors are nonpositive-displacement machines, often arranged in series on a line to achieve multistage compression.

n: the amount of force needed to crush the sides of pipe until it caves in on itself. The pipe collapses when the pressure outside it is greater than the pressure inside it.

n: The required pressure collapsing casing from outside.

external hydrostatic pressure that will cause the onset of pipe yielding. Heavily influenced by tension loads on the pipe.

n: a type of orifice meter chart that indicates the differential pressure and static pressure for a particular time period. The pressures can be read directly from the chart instead of being calculated from information given on the chart.

n: (DST) the conventional method of formation testing. The basic drill stem test tool consists of a packer or packers, valves or ports that may be opened and closed from the surface, and two or more pressure-recording devices. The tool is lowered on the drill string to the zone to be tested. The packer or packers are set to isolate the zone from the drilling fluid column. The valves or ports are then opened to allow for formation flow while the recorders chart static pressures. A sampling chamber traps clean formation fluids at the end of the test. Analysis of the pressure charts is an important part of formation testing.

n: during drilling or affter well completation ,lower the drillstem tester into the layer to make the pressure build up test so as to eatimate the layers and the fluid parameters

n: a multiplying factor used when calculating gas flow rate. This factor corrects for the reduction in fluid density that a compressible fluid experiences when it passes through an orifice as a result of the increased fluid velocity and the decreased static pressure. Also called expansibility factor.