Dynamic characteristics analysis of rotary coupled controller in directional well

With the advancement of the oil and gas industry, ultra-deep wells, extended-reach wells, and long-distance horizontal wells are increasingly prevalent. The drilling condition is very complicated. Therefore, this paper develops the rotary coupled controller (RCC) for directional wells to improve the efficiency of directional drilling. The structure and working principle of RCC are introduced, and the advantages of sliding directional drilling and rotary steerable drilling are combined. According to the working characteristics of RCC, the drilling string dynamic model of horizontal well is established. The results indicate that, compared with the dynamic model with or without RCC, the bit angular velocity fluctuates periodically in the range of 0–16.2 rad/s without RCC. The bit movement is unstable and always lags behind the upper drill string. After using RCC, the angular velocity initially fluctuates briefly before stabilizing at approximately 31.2 rad/s. The torque result of drill string system is always in dynamic friction state, indicating that RCC can reduce friction and suppress stick–slip vibration. This tool serves as a valuable reference for achieving high-precision and high-efficiency directional well drilling.