Study on Rock Breaking Mechanism and Field Test of Prismatic Cutter

Abstract

The rock breaking mechanism and effect of prismatic cutter is not clear, which leads to errors in the application and design of prismatic cutter, and often fails to achieve the expected effect. Therefore, the finite element method is used to carry out numerical simulation analysis of prismatic cutter. The change law of cutting force in the process of rock breaking is analyzed. Rock breaking mechanism is studied. What’s more, single cutter straight-line scraping experiment and field application are carried out to verify correctness. The results of numerical simulation and experiment show that the stress state of rock is obviously different between prismatic cutter and conventional plane cutter in the process of rock breaking. Under the same conditions, the tangential force and the fluctuation of tangential force required by prismatic cutter in cutting sandstone are less than those of conventional plane cutter. The field test of PDC bit with prismatic cutter shows that it has high rock breaking efficiency and good impact resistance in specific formation. The results show that the prismatic cutter destroy the rock mainly through the action of tension and shear. The tangential force and torque are smaller. The impact resistance and wear resistance are higher, which can effectively improve the rock breaking efficiency and increase the service life of the bit.