Optimization and application analysis of special-shaped cutters based on full-scale bench experimental assessment

The irregularly shaped cutter technology can effectively address the challenges of rock breaking and rate of penetration (ROP) enhancement in deep hard formations. The key to this technology lies in optimizing the selection of irregularly shaped cutters suitable for the target formation and operational conditions. This paper establishes a comprehensive method for selecting irregularly shaped cutters, which takes into account both the aggressiveness and reliability of the cutters during drilling in specific formations and under specific operational conditions. Additionally, a laboratory evaluation method for full-scale bit rock-breaking effectiveness has been developed, and the validity of the cutter selection results has been verified through field applications. Experimental results show that the optimized PDC bit significantly reduces the risk of cutter damage when drilling igneous rocks. The combined effect of the axe-shaped cutter's aggressive structure and dispersion mechanism substantially lowers the bit torque level, while the ROP increases by up to 59%. Field applications demonstrate that, compared to the last drilling run in the same formation, the bit optimized using the selection method proposed in this study achieved an average ROP improvement of 191.43%. This method enhances the adaptability of PDC bits to the formation and operational characteristics of target wells, providing technical support for improving rock-breaking efficiency and ROP in deep hard formations.