Simulation Method of Borehole Trajectory Based on Vector Similarity

Abstract

For the well planning stage, the application of the designed borehole trajectory (DBT) predicts that the torque and drag is low, and it is impossible to accurately analyze the difficulty and risk of drilling construction. This paper proposes a method for comparing and selecting borehole trajectory control parameters based on the vector cosine similarity. The database for borehole trajectories has been established, and two vectors were designed to represent the control state of the actual borehole trajectory (ABT) and the simulation position of the simulated borehole trajectory (SBT), respectively, and the similarities of them were used as the reference standard for simulating the behavior of engineers to determine the control parameters. Random selection of control parameters was set to further simulate the behavior of the engineer. The feasibility of the method was evaluated by using the control deviation and torque and prediction deviation. The case well experiment results show that the control deviations of the SBT and the ABT relative to the DBT are close, and the fluctuation law is similar. In rotary drilling conditions, the torque calculated using SBT is slightly higher than the actual drilling torque, and the maximum deviation is less than 10%. In tripping out condition, the hook loads are slightly higher, and the maximum deviation is less than 9%. In additional operating conditions, the hook loads calculated by the SBT are the same as the actual hook loads, and the maximum deviation is less than 4%. This work provides a feasible method to simulate ABT in the well planning stage and enhances the reliability of the predicted torque and drag results.