دیکشنری تخصصی مهندسی نفت - نسخه آنلاین

a pore pressure higher than a column of sea water for that true vertical depth.

n: (ECD) the increase in bottomhole pressure expressed as an increase in pressure that occurs only when mud is being circulated. Because of friction in the annulus as the mud is pumped, bottomhole pressure is slightly, but significantly, higher than when the mud is not being pumped. ECD is calculated by dividing the annular pressure loss by 0.052, dividing that by true vertical depth, and adding the result to the mud weight Also called circulating density, mudweight equivalent

n: The effective drilling-fluid weight at any point in the annulus of the well bore during fluid circulation.ECD includes drilling-fluid density, cuttings in the annulus, and annular pressure loss.

the effective fluid density that the formation sees when the friction pressure on the fluids returning to surface is added to the fluid density.

n: the increase in the temperature of the earth with increasing depth. It averages about 1�F per 60 feet (1�C per 18.3 metres),but may be considerably higher or lower.

n: 1.The rate of increase in temperature per unit depth in the Earth. Although the geothermal gradient varies from place to place, it averages 25 to 30 oC/km [15 oF/1000 ft]. 2.The natural increase of temperature with depth in the earth. Temperature gradient

the gradient reflecting the amount of temperature rise as the well depth increases. Normally about 1.1 to 1.8o F per 100 ft of true vertical depth increase.

abbr: measured depth.

measured depth – the along hole measurement of depth of the well. As opposed to true vertical depth (TVD).

n: (MD) the total length of the wellbore, measured in feet along its actual course through the earth. Measured depth can differ from true vertical depth, especially in directionally drilled wellbores. Compare true vertical depth.

n: the distance measured along the path of the wellbore (i.e. the length of the drill string).

depth measurement of a wellbore as measured along the drill pipe without respect for vertical penetration.

n: pressure measured relative to zero pressure. true vertical (TVD) n: the depth of a well measured from the surface straight down to the bottom of the well. The true vertical depth of a well may be quite different from its actual measured depth, because wells are very seldom drilled exactly vertical.

the vertical depth from the surface to the depth of interest. Used for formation comparison and calculation of hydraulic pressures.

abbr: true vertical depth.

True Vertical Depth.

true vertical depth from the rotary table.