Experimental research on working principle of the composite single-cone bit

The composite single-cone bit is a new structure of single-cone bit, which breaks the limitation of the one-piece cone structure of existing single-cone bit. The new bit structure makes it possible to apply PDC cutters with strong wear resistance to single cone bit. PDC cutter is more suitable for rock breaking by scraping. In this paper, rock breaking and comparative drilling experiments of composite single-cone bit are carried out. The experiments verified the working principle of the new composite bit. The effective combination of fixed and unfixed cutting structures in the new bit can form complex cross-scraping. The comparative drilling experiments show that the new composite bit has higher rock breaking efficiency than the common single-cone bit, and it is more energy-saving for cross-scraping. The application of PDC cutters can improve the wear resistance of bit cutters and prolong the service life of bit. The research results can provide basic support and reference for subsequent research on the design, development, and application of this new type of bit. •The composite bit proposes a combination of fixed and unfixed cutting structure.•PDC cutters are directly used on the single-cone bit.•The cutters of the composite single-cone bit form complex cross-scraping.•The composite single-cone bit has higher rock breaking efficiency and saves energy.•The application of PDC cutters improves the wear resistance of bit cutters and can prolong the service life of bit.