Research On Improving The Stability Of PDC Bits

The stability of the working state of the PDC bit directly affects the service life and rock breaking efficiency of the drill bit.In the previous calculation model of the lateral unbalance force of the PDC bit,the influence of the shape of the bottom hole was not considered.Different shape of the bottom hole will cause the drill to be subjected to different rock reaction forces,which will affect the movement state of the drill bit.Therefore,it is necessary to study the mechanical model of the bit cutting from the shape of the bottom hole,optimize the calculation model of the unbalanced force of the bit,and finally obtain a method to improve the working stability of the PDC bit.In this paper,aiming at improving the working stability of the drill bit,it is clear that the essential cause of the unstable working state of the drill bit is the unbalanced force,and the objective function is that the drill bit is subjected to the lateral unbalance force.The test method of single-tooth cutting of different shapes of limestone is used to explore the relationship between the shape of the bottom hole and the force of the cutting teeth.The finite element software is used to simulate the rock process of single-tooth and singlerow teeth.Verification,at the same time,the mathematical relationship between the force of the cutting teeth and the shape of the bottom hole.It is brought into the PDC bit lateral force calculation model to complete the optimization of the model and establish the relationship between the shape of the bottom hole and the stability of the drill bit.Finally,using the shape of the bottom hole and the contour of the crown of the drill bit,the method of improving the working stability of the PDC bit is proposed.