28.7 Section Summary

Subsea positioning accuracy is dependent on the equipment used, the water depth, and the absence of human error in the taping and recording of offsets. It is important that the SFP communicates well with the marine survey department to ensure the following

1. That both departments are using the same coordinate reference system and datum
2. That vertical references are clearly understood and agreed
3. That the method of calibration of seabed arrays is understood and adequate for the job
4. That a clear report is produced of the final positions and their uncertainties
5. That subsea well positions and not topside centres are used for well coordinates