The Finite Element Simulation and Test of Rock Breaking by Non-Planar PDC Cutting Cutter

In order to provide references for PDC bit design, the rock breaking performance of triangular prism, axe-shaped and the conventional planar PDC cutting cutter was studied. 3D finite element models of vertical press-in and linear cutting into rocks were established by using finite element software, which simulated the processes of vertical press-in by cutters with the same tooth arrangement angle, and linear cutting of homogeneous/heterogeneous rocks with different cutting depths. It is found that there are significant differences in rock breaking, depending of the shape of the cutters, which can be quite different shapes. Compared with the conventional planar PDC cutters, triangular prism PDC cutters are more easily pressed into the formation to form a crushed pit. When breaking homogeneous sandstone, triangular prism and axe-shaped PDC cutters require less cutting force, and they establish a uniform contact with the rock, resulting in creating a larger pre-crushing area of the rock. For breaking heterogeneous rocks, the tangential force fluctuation of the triangular prism and axe-shaped PDC cutters is small, and it is more easily to break the rocks. According to the simulation results, the test of mixed granite stratum drilling with PDC bit with triangular prism cutters was conducted, and the test results showed that the finite element simulation could provide references for the design of a PDC bit.