Abstract: There are many calculation techniques for determining the trajectory of the wellbore. The most common techniques are tangential method, balanced method, angle averaging method, radius of curvature method and minimum curvature method. This paper presents a comparison study among five different models used to calculate the well trajectory using actual field data for different well profiles (build & hold, S shape and modified S trajectory). A new model was developed for calculating the well trajectory and compared with different models mentioned above using the same data and the same well profiles. The results obtained during the present work indicated that the new model is more accurate than the other methods for calculating the true vertical depth. At calculate Horizontal displacement, northing and easting different methods give very close agreement, with the exception of the tangential method.

Keywords: Trajectory, tangential method, balanced method, angle averaging method.