Incipient fault detection of rotary steerable drilling tool equipment

Abstract

Rotary steering drilling system is a high-end piece of equipment in oil and gas development. The reliable operation of its core equipment, the dynamic point-the-bit rotary steerable drilling tool (DPRSDT), is an important prerequisite for the normal operation of the drilling system. In this paper, the problem of incipient fault detection is investigated for the DPRSDT equipment based on the model method, which is expected to provide an important guarantee for the operation, maintenance, and health management of the system. First, the mathematical model of the DPRSDT is derived using the mechanism modeling method. Then, the moving weighted average approach is employed to improve the sensitivity of residuals to incipient faults. Based on the characteristics of the noncentral $\chi^2$ distribution, the detectability of incipient faults is analyzed in a statistical sense, and the window length and weight are derived, which ensures that the false alarm rate and missed detection rate can be reduced below the tolerance level. Finally, an experiment is performed in the rotary steerable drilling tool prototype to verify the effectiveness of the proposed method.