Dynamic characteristics analysis of hydraulic clutch controller in directional wells

Ultra-deep wells, extended-reach wells and long-distance horizontal wells are becoming more and more common in the development process of oil and gas industry. And it is gradually shifting toward new unconventional oil and gas resources, resulting in the complex wellbore trajectory. Therefore, this paper proposes a hydraulic clutch controller (HCC) for directional wells, which can well complete the directional drilling. This paper introduces the structure and working principle of the HCC, and it incorporates the advantages of sliding directional drilling and rotary steerable drilling. Based on the working characteristics of HCC, the drill string dynamics model in the horizontal wells is established. Compared with the calculation results of dynamic model with HCC or not, the research results show that the angular velocity of drill bit fluctuates periodically in the range of 0–11.86 rad/s without HCC. The drill bit motion is erratic and always lags behind the upper drill string. With the action of HCC, the angular velocity fluctuates in short time at the initial phase and gradually stabilizes at about 8 rad/s. And the torque results of drill string system are always in dynamic friction condition. The HCC can reduce the friction and suppress stick–slip vibration phenomenon. The developed tool provides an alternative approach for high-precision and high-efficiency drilling of directional wells.