22.1 Checking raw data

Raw data observed in the field can be checked for basic quality control. Any set of MWD raw sensor data can be used to calculate a field strength and dip angle using the following formulae.

The Dip Angle can be calculated from the following simple formula:

Where Bt = square root of (Bx2 + By2 + Bz2) ie the total Magnetic Field
And Gt = square root of (Gx2 + Gy2 + Gz2) i.e. the total Gravity Field

In general if the Field Strength calculated is within 300nT of the expected field and the dip angle to be within 0.25 of the expected dip, we would consider the MWD to be within acceptable tolerances.