The Lip Structure Design Of Impregnated Drilling Bit For Hard And Dense Rock Formation

As the depth of geological drilling continues to increase,the possibility of drilling hard and dense rock formations is increasing.When a diamond drill bit is drilled in a hard and compact rock formation,on the one hand,the rock diamond is pressed into the rock to a small depth,resulting in a hard diamond bit.In the dense rock formation,the rock can only be crushed by surface wear and fracture,and the drilling efficiency is low.On the other hand,the weak abrasiveness of the rock and the formation of fine cuttings lead to the failure of the diamond in the drill bit to be timely,which is prone to "slip" phenomenon.In view of the "slip" and low drilling efficiency of the impregnated diamond drill bit in the hard and compact rock formation,the fracture mechanism of the impregnated diamond drill bit in the hard and compact rock formation is analyzed,and the energy consumption per unit volume from the rock is analyzed.From the angles of "angle of free cutting" and "partial volume crushing",the idea of using rock local volume crushing to increase drilling efficiency is proposed and the combination of the tongue-and-groove super-tooth structure and the low-bit tooth structure is designed.The ?36-18 impregnated diamond drill bit was designed based on the calculation of the drill bit nozzle,the groove tooth strength and the optimal design of the lower bit and the ridge.The COMSOL software was used to simulate the nozzle of the designed bit,which verified the rationality of the bit size design.Using the indoor micro-drilling experimental platform,1 m was drilled in the granite at the same drilling speed of 0.5 m/h and the same speed of 300r/min.The results show that the average drilling pressure of the new lip-faced drill bit is about 1/2 times that of the flat-bottomed bit.The new lip-faced drill bit produces a rock chip size of about 300 mm.-5 times,indicating the feasibility of the designed bit.Finally,the wear conditions of the two drill bits are compared and analyzed accordingly,which provides a basis for the further design of the drill bit.