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variation. That may or may not be true. For example, a truck passing during the average or at the time of the observation may affect that accuracy.
7. u y lcul on M hods
7.1 Examples of current methods
Over the years there have been several methods of calculating survey positions from the raw observations of measure depth, inclination and direction. At the simplest level if a straight line model is used over a length dM with inclination I and Azimuth A, we can derive a shift in coordinates as in figure 42. This simple technique is often referred to as the Tangential Method and is relatively easy to hand calculate. However, the assumption that the inclination and direction remain unchanged for the interval can cause significant errors to accumulate along the wellpath.
Figure 42: Tangential method to derive a shift in coordinates.
An mpo m n o hsw s h ‘A g Angl M hod’wh h zmuh nd ncln onus d n h bo fomul s was simply the average of the values at the start and end of the interval.
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