The Numerical Analysis of Suction Port Position under the Stress and Velocity Field
The shaft drilling diameter is up to φ7m, Larger borehole and deepened section make slow drilling problem more and more prominent, which has seriously affected the drilling cost and drilling cycle, thus affecting the exploration and development speed of entire coal mine and the oil field. At present, the improvement of drilling speed and efficiency of φ7m and larger diameter section has become a technical problem needed to be solved. In order to improve the drilling speed of φ7m diameter and larger diameter boreholes, super twin-stage bit is recommended. It has an enlarger drill (φ 4.5m) than average bit using twin-stage structure.,A small guide hole is drilled the first, followed by drilling the borehole. On the other hand, the stratum drilled makes larger free surface to release the ground stress, which will increase ROP, reduce drilling time and quicken the speed of well completion.Starting from the mathematical model of stress field and velocity field, this paper establishes the unit models of bottom-hole stress field and velocity field. Through the finite element analysis, it analyzes influence of different slurry suction port position on rock breaking efficiency, which has high reference value for the design of super twin-stage drill bit.