4.2.4 Trajectory Data Object

The trajectory data object (Trajectory) (Figure 4.2.4.3-1) is used to capture information about a directional survey in a wellbore. The data from the survey actually defines the wellbore trajectory. A trajectory is a top-level data object and must reference a parent wellbore using a data object reference.

While drilling a well, contractors conduct measurement-while-drilling (MWD) surveys. MWD typically takes measurements of wellbore inclination from vertical and magnetic direction from north. Using basic trigonometry, a 3D path of the wellbore can be produced. The location in the wellbore where a measurement is taken is referred to as a survey station or trajectory station (TrajectoryStation). The set of data collected at all stations defines the wellbore trajectory.