Kinematic Characteristics of Vertical Runner and Numerical Simulation Analysis of Rock Breaking

Abstract

In order to solve the problems of PDC teeth easy to collapse and fail in hard, hard and soft interlaced formations and gravel bearing formations, low mechanical speed, and difficult orientation caused by high torque response of pdc bits in directional drilling, this paper proposes a new type of composite bit with vertical wheels on the blade. Through theoretical analysis, the rotating conditions of the vertical wheel are obtained, that is, the contact angle of the cutting teeth of the vertical wheel must be greater than the center angle of its two adjacent teeth. At the same time, the cutting tracks generated by the previous vertical wheel unit experiments are analyzed, and the causes of different cutting tracks are obtained. Finally, the rock breaking of the PDC teeth under the pre damage of the vertical wheel is numerically simulated and analyzed, and it is concluded that the force on the PDC teeth is closely related to the relative height between the cutting teeth of the vertical wheel, It increases with the increase of relative height. When the relative height is 2mm, the tangential force on the PDC tooth is 4.78 times that when the relative height is 0mm, and the axial force is 2.47 times that when the relative height is 0mm. At the same time, the relationship between the force on the PDC teeth and the normal deflection angle and the rake angle of the vertical roller is not obvious.