Selection of extended reach well trajectory design scheme based on entropy weight method

The trajectory design of extended reach well is quite important for its safe and efficient drilling. The drilling of extended reach well faces several problems, such as poor wellbore stability in the long open hole section, high torque and drag, serious string buckling and difficult hole cleaning, so its trajectory design needs comprehensive analysis and evaluation. In this paper, a model for evaluating the trajectory design scheme of extended reach well was established based on the entropy weight method, in which the weights are calculated and the schemes are scored by making full use of the fluctuation of evaluation indexes, so that the trajectory design scheme of extended reach well is quantitatively evaluated. It has been successfully applied to the drilling of extended reach well in one certain oilfield. This research not only provides a new idea and a guidance method for the selection of trajectory design scheme of extended reach well, but also a technical reference for the subsequent drilling technology optimization and risk evaluation of extended reach well.