دیکشنری تخصصی مهندسی نفت - نسخه آنلاین

n: See magnetic declination。

n: 1. the angle, variable with geographic position, between the direction in which a magnetic needle points and the true meridian. 2. a turning aside or swerving.

n: an imaginary contour on the earths surface joining places where the magnetic declination is the same.

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

n: a device used to determine the direction and drift angle of a deviated wellbore. It uses a magnetic compass to measure magnetic direction, which differs from true direction by the amount of local declination.

n: the apparatus that measures drift azimuth and deviation angle.

A mathematical transformation of the total magnetic intensity field at its observed inclination (I) and declination (D) to that of the magnetic equator. I=0o.

A mathematical transformation of the total magnetic intensity field at its observed inclination (I) and declination (D) to that of the north magnetic pole. I=90o, D=0.