An Innovation in 3-D Drilling Trajectory Design Using Concept of Constant Curvature

Abstract

This paper focuses on the use of the 3-D drilling trajectory equations derived from the concept of constant curvature. It is shown that the constant curvature equations are specially useful for horizontal drilling. Three examples of using the constant curvature method are presented to demonstrate the practical usefulness of the proposed concept. The results obtained reveal that the well trajectory with constant curvature is not only consistent with directional performance of deflection tools, but also yields less dogleg severity. This, in turn, should increase the fatigue life of drillstring elements passing through the curved segments of the hole. Finally, drag and torque computations show that, thanks to less dogleg severity, the drag and torque are expected to be less in holes designed to have constant wellpath curvature.