دیکشنری تخصصی مهندسی نفت - نسخه آنلاین

n: 1. in directional drilling, the direction of the wellbore or of the face of a deflection tool in degrees (0-359") clockwise from true north. 2. an arc of the horizon measured between a fixed point (such as true north) and the vertical circle passing through the centre of an object.

n: Reflecting the direction of wellbore deflection.

n: a wheel or disk mounted to spin rapidly about one axis but free to rotate about one or both of two axes perpendicular to each other. The inertia of the spinning wheel tends to keep its axis pointed in one direction regardless of how the other axes are rotated.

n: a wheel or disc mounted to spin rapidly about one axis,but free to rotate about one or both of other two axes.the inertia of the wheel keeps the axis aligned with the reference direction (true north).

n: a map that shows the isogonic lines joining points of magnetic declination, which is the variation between magnetic north and true north. For example, in Los Angeles, California, when the compass needle is pointing toward north, true north actually lies 150 east of magnetic north. See declination.

n: an imaginary line on a map that joins places on the earths surface at which the variation of a magnetic compass needle from true north is the same. This variation, which may range from 0 to 30 or more degrees either east or west of true north, must be compensated for to obtain an accurate reading of direction.

n: th angle between true north and magnetic north,this varies with geographical location, and also changes slightly each year.

n: a surveying tool that automatically aligns itself with true north (also called north-seeking gyro).

n: the direction of the north geographic pole-as opposed to the north magnetic pole, which is several hundred miles away, toward Hudson Bay.

n: the angle by which a compass needle deviates from true north.