Design and rock-breaking performance of axe-shaped PDC cutter for hard sandstone of Shaximiao Formation, northeastern Sichuan Basin

Axe-shaped PDC cutter is well performed in rock breaking owing to its unique structure, but its rock-breaking performance and optimal working angle remain unclear. An evaluation method of total specific energy for rock breaking by cutting combining with pressing was established. By using the rock-breaking simulation model, the working angle optimization of axe-shaped PDC cutter was investigated, and a simulation was conducted on the axe-shaped PDC cutter with optimized working angle. The results show that the composite rock-breaking specific energy of the axe-shaped PDC cutter changes in an “N” pattern as the working angle increases. The axe-shaped PDC cutter with the working angle of 130° is excellently performed in hard sandstone, with the cutting force, cutting rock-breaking specific energy, pressing rock-breaking specific energy, and composite rock-breaking specific energy of 35%, 20%, 5.9% and 10.5% lower respectively than that of conventional PDC cutter. Laboratory experiment shows that the cutting rock-breaking specific energy of the axe-shaped PDC cutter reduces by 35.2% and shows a greater penetration. The research provides a theoretical foundation for customization of PDC cutter for hard sandstone of Shaximiao Formation in northeastern Sichuan Basin.