Drift:

An ocean current’s speed of motion.

2.

An observed change, usually uncontrolled, in meter performance, meter factor, etc., that occurs over a period of time.

v:1.

To move slowly out of alignment, off center, or out of register.

2.

Gauge or measure pipe by means of a mandrel passed through it to ensure the passage of tools, pumps, and so on.

Terms Related to Drift

• Drift angle

  The angle at which a wellbore deviates from the vertical, expressed in degrees, as revealed by a directional survey. Also called angle of deviation, angle ...

• Micron

  One-millionth of a meter, a metric unit of measure of length equal to 0.001 meter.

• Rate of penetration (rop)

  A measure of the speed at which the bit drills into formations, usually expressed in feet (meters) per hour or minutes per foot (meter).

• Deviation

  Departure of the wellbore from the vertical, measured by the horizontal distance from the rotary table to the target. The amount of deviation is a ...

• Deviation survey

  An operation made to determine the angle from which a bit has deviated from the vertical during drilling. There are two basic deviation-survey, or drift-survey, ...

• Stability meter

  An instrument to measure the amount of voltage needed to break down invert emulsions.

• Bleed

  To drain off liquid or gas, generally slowly, through a valve called a bleeder. To bleed down, or bleed off, means to release pressure slowly ...