Algorithm facilitates preplanning wellbore trajectories : Nicholson, J T Oil Gas JV89, N5, 4 Feb 1991, P45–49

Abstract

An algorithm has been developed for generating and navigating well bore trajectories with prescribed initial and final coordinates, and angular conditions. This type of three-dimensional trajectory occurs while planning relief, extended reach, horizontal, and noncollinear multitarget wells. The selection of a mechanically feasible well bore trajectory is based upon optimizing the drillstring loads and the steerability of the trajectory. The use of the algorithm is illustrated with detailed examples. The algorithm can be easily solved on a personal computer. The basic nature of the algorithm differs from that of conventional directional drilling, planning, and survey techniques in that no assumption was made as to the shape of the trajectory. The algorithm generates data bases that can be used to compare the accuracy of survey calculation methods. The algorithm can be generalized in two ways. One or two more derivatives at the terminal ends can be prescribed. This is equivalent to specifying the initial and final curvature and torsion. Such generalizations would increase the order of the polynomial from a third order to a fifth and seventh order polynomial.