Factors to Influence the Trajectory Control Ability of a Reverse Push-the-Bit Rotary Steerable System

Abstract

The reverse push-the-bit rotary steerable method based on the principle of a “labor-saving lever” provides a feasible technical solution for further improving trajectory control ability of the rotary steerable drilling system, further prolonging the system’s service life and further increasing the system’s drilling speed. In order to reveal the working characteristics of such a method deeply, the influence of the key structural parameters of the rotary steerable drilling system on its trajectory control ability is studied based on the finite element method. The results show that, with the certain distance from the bit to the centralizer, the structural parameters of the flexible joint, the distance from the flexible joint to the paranoid mechanism, and the distance from the paranoid mechanism to the centralizer are the main factors to affect trajectory control ability. Reducing the stiffness of the flexible joint, shortening the distance from the flexible joint to the paranoid mechanism, and optimizing the distance from the paranoid mechanism to the centralizer are the keys to improve trajectory control ability to the utmost. The performance of the reverse push-the-bit rotary steerable method with optimized parameters is obviously better than the existing method, but its actual drilling effect needs to rely on on-site verification and further optimization.