Comparison of the directional survey calculation methods applied on real well data

• The six most common directional survey calculation methods are described.
• The methods are compared to each other with relative differences approach.
• Calculated trajectories from the methods are visualized.
• The method for field and computer application is recommended.

Directional surveys have been around since the beginning of drilling in the oil and gas industry. The tools have constantly been changing during the years, which cannot be said for the calculation methods. The most common directional survey calculation methods were compared in this paper. The methods were compared with the introduction of relative differences, where each or every second, every third, or every fifth survey station is taken into consideration. The results were plotted graphically over the length of the wellbore. They were also visualized. The tangential method was found to be inappropriate for its use in any circumstances. The average angle method or balance tangential method should be used for field application whereas the helical arc method is recommended for computer calculations.