MANUAL – REFLEX EZ-TRAC™ | 20
6 About Survey Data
This chapter describes the survey data provided by magnetic
instruments from
REFLEX™.
6.1 Introduction
REFLEX™ magnetic instruments measure and displays the following
basic survey data:
Azimuth 0º to 360º
Dip ±90º
Magnetic field strength 0 to 100,000 nT
Magnetic dip ±90º
Gravity tool face 0º to 360º
Magnetic tool face 0º to 360º
6.2 Dip and azimuth
Dip, or inclination, is the angle from the horizontal plane to the
borehole. Azimuth, or the direction of the dip, is the angle from north
to the horizontal projection of the borehole.
The readings of dip and azimuth are absolute measurements, at a
particular depth, of the direction of the instrument relative to the
gravitational and magnetic vectors.
The dip and azimuth angles, along with the depth of the survey
station, are used to calculate the regional and local coordinates of the
survey station.
The mathematic algorithms needed for the calculations of the
coordinates are included in
REFLEX™ SProcess.
6.3 Magnetic components
Based on data from the magnetometers and the accelerometers,
two types of magnetic data are calculated; total magnetic field
strength and magnetic dip.
6.3.1 Total magnetic field strength
The Earth’s total magnetic field strength is reported in nanoTesla
(nT). This is the unit in which magnetic survey maps are often
contoured. This is the force exerted by the Earth’s magnetic field at
any particular point. The magnetic field increases in strength towards
the poles, but have minimal change down the borehole.
Several items will distort the Earth’s magnetic field, such as solar
wind from the sun, rocks (wide range of magnetic influences) and
man made ferrous objects.
6.3.2 Magnetic dip
The Earth’s magnetic field does not run parallel to the Earth’s surface.
The magnetic dip is the angle from the horizontal plane to the
magnetic lines of force.
To Next Page
Loading...
Need help?
General
