LAUSR

Abstract The Stinger PDC cutter has a better performance than the conventional PDC cutter drilling for hard, interbedded and highly abrasive rocks. Although researchers have investigated the cutter's characteristic, such as impact resistance, wear resistance and cutter's life, the cutting behaviors of the Stinger PDC cutter still remains unclear. In this study, the single cutter tests were carried out with a Stinger PDC cutter and a conventional PDC cutter as comparisons. The cutting force, cuttings size, surface topography along the cutting trajectory and microscopic morphology of the fracture surface were compared and analyzed. The results show that the average cutting force of a Stinger PDC cutter is 46.14% lower than that of a conventional PDC cutter. The proportion of large cuttings (r > 2.36 mm) generated in the Stinger PDC cutter test is higher than that in the conventional PDC cutter test. In addition, the energy consumption of breaking rocks by a Stinger PDC cutter is 34.09% lower than that by a conventional PDC cutter. The cutting trajectory in the Stinger PDC cutter test has a “V” shape and the surface is relatively rough (Sa = 617.08 μm), while the conventional PDC cutter produces a “U” shape cutting trajectory and the surface is relatively smooth (Sa = 462.18 μm). Furthermore, the SEM analysis shows that the Stinger PDC cutter breaks granite mainly by tensile stress, which is different with the conventional PDC cutter by shear stress. The key findings of this work will help to reveal the rock-breaking process and mechanism with the Stinger PDC cutters.