Research Status and Technological Development Trends of Hybrid Drill Bits

In petroleum drilling engineering, the drill bit is the primary rock-breaking tool, and its performance directly affects drilling cost and operational efficiency. As oil and gas exploration and development extend from shallow formations to deep and ultra-deep reservoirs as well as increasingly complex geological environments, challenges such as high rock hardness, strong abrasiveness, and poor drillability significantly increase the difficulty of rock breaking, placing higher demands on drill bit structural design and service reliability. The PDC–roller-cone hybrid drill bit combines the shearing rock-cutting mechanism of PDC cutters with the crushing action of roller cones, enabling higher rates of penetration, improved directional control capability, and longer service life in hard formations, highly abrasive formations, and directional drilling operations. Considering that the understanding of the rock-breaking mechanism and the theoretical basis for structural design of hybrid drill bits remain incomplete, this paper systematically reviews recent research progress and engineering applications in China and worldwide. The structural characteristics and operating principles of hybrid drill bits are analyzed, and the shear–impact coupled rock-breaking mechanism as well as typical failure modes are discussed. Furthermore, their performance advantages and limitations compared with conventional roller-cone bits and PDC bits are evaluated under practical drilling conditions. Based on these analyses, structural optimization strategies and future technological development directions are proposed to support the engineering application and further research of hybrid drill bits.