12.2.3.3 Deviation Survey

Before a trajectory can be computed in a model coordinate system, it is usually represented by a deviation survey. It is useful to transfer this survey when a trajectory is not yet computed or for quality control.

The survey references MD datum pointing to a measured depth reference, indicates the location of the first survey station in the model, and then, for each station, specifies a measured depth, azimuth, and inclination. To distinguish it from other intermediate versions of survey, an "is final" tag is used to indicate if this is the currently accepted version of the survey. The deviation survey can be associated with a WITSML survey.