Working mechanism and experimental study of split bit

Abstract

As a component directly acting on the rock in the drilling process, the low efficiency of rock breaking will occur when the bit is drilled. In this paper, a new type of split drill is designed in which the cutting ring can move relatively independently, as well as the kinematic analysis model of the cutting tooth is established. The displacement, velocity and acceleration values of the specific points on the cutting tooth ring of the bit are obtained, which verifies that the small cutting ring at the center of the split cone bit can improve the rock breaking efficiency at the center of the bit. Through the comparison experiments of different types of bits and split bits, the results show that the mechanical drilling rate of split single-tooth bits and triple-tooth bits increased by 11.7% and 12.4%, respectively, in Beipei limestone conditions. Meanwhile, the speed of those two increased by 8.9% and 11.4%, respectively, in Wusheng sandstone conditions, which effectively improved the rock-breaking performance. Combined with the results of bottom hole model, the characteristics of impact, invasion and cutting in the process of tooth rock breaking can be obtained, which effectively improves the rock breaking performance and verifies the rationality of bit design and the correctness of theoretical analysis.