Important Elements and Best Practice

Topic Version1Published11/11/2016
For StandardWITSML v2.0

It is important to include certain elements in the trajectory and trajectory station data objects for them to be both valid and of practical use. Most required elements relate to object identification (UUIDs), etc. and high-level concepts, which are implemented as requirements in the schemas. Other elements represent a “best practice” that is helpful for the Trajectory data object to be properly interpreted.

Trajectory Object, Best Practice:

  • Definitive: Identifies a final, definitive trajectory, as distinguished from other temporary or partial ones.
  • MdMn and MdMx: minimum and maximum measured depths represented by the contained trajectory stations.
  • ServiceCompany: name of the contractor who provided the service.

Trajectory Station:

  • Required:
  • uid: unique identifier within the trajectory scope, for a trajectory station instance.
  • TypeTrajectoryStation: specifies the type of a directional survey station.
  • Md: measured depth, along the trajectory path, identifying where the survey measurement was taken.
  • Best Practice:

Note: If inclination (Incl) and azimuth (Azi) are not provided, then Tvd, DispNs, DispEw should be; otherwise, it isn’t possible to properly interpret the trajectory path.

  • Incl: hole inclination angle, from vertical line descending from the well head.
  • Azi: hole azimuth, corrected to a well’s azimuth reference.
  • Tvd: true vertical depth of the measurement from vertical.
        • DispNs: north-south offset from vertical, positive to the north.
        • DispEw: east-west offset from vertical, positive to the east.
  • DTimStation: date and time the station was measured or created.
  • StatusTrajStation: status of the station: open, rejected or position.
Figure UML diagram of the trajectory data object.