Design and mechanical analysis of a new automatic vertical drilling tool used in a slim borehole

A new kind of electronic-controlled automatic vertical drilling tool is developed to satisfy the requirements of slim-hole, which has a unique push-actuator to push-the-bit. This paper introduced the mechanical structure and working process of the automatic tool, and analyzed in detail one of the most critical component - the push-actuator. The analysis reveals that, with the pitch-row of studdle increasing form 20mm to 24mm, the ratio of push-out force to forward force gradually decreases from 2.04 to 0.78, and the completion time of push-out process reduces from 75.8s to 42.8. This result indicates that, using studdles with shorter pitch-rows, larger straightening force could be obtained. On the contrary, studdles with longer pitch-rows could realize more quickly sensitive response of deviation control. These unique characters make the vertical drilling being able to be adapted to different geological conditions and technological requirements, the applicability and feasibility of the drilling tool remarkably improved. Thus this vertical drilling tool owns a great promotional value for oil and gas exploration. (paper)