The development of a novel electric-hydraulic orienter used for coiled tubing drilling

Due to the limitation of running mode, the coiled tubing cannot rotate in the borehole, which makes the orientation difficult, so as to seriously impact the application and popularization of coiled tubing drilling technology. In this regard, a kind of electric-hydraulic orienter used for coiled tubing drilling was designed. The orientation of coiled tubing is realized by adjusting the tool face of bottom hole assembly (BHA) by means of electronic control-hydraulic drive-mechanical drive. Then, the effects of friction coefficient and contact dip on mechanical efficiency and output torque were clarified by analyzing the force applied on the mechanical drive system. Finally, the dynamic characteristic model of hydraulic drive system was established to simulate the whole process of hydraulic drive. In this way, the change of piston displacement and force in different stages and the relationship between the impact force on the drive contact surface and the movement velocity of the piston are figured out. The research results provide the theoretical basis for the optimal design of orienter’s mechanical drive system and hydraulic drive system.