High penetration rates and extended bit life through revolutionary hydraulic and mechanical design in PDC drill bit development

PDC drill bit developments have been made to achieve higher penetration rat es and longer life, involving a compromise between open, light set, bits fo r speed, and heavy set ones for durability. Developments are described whic h provided the benefits of both in a revolutionary hydraulic and mechanical design. The hydraulic design causes mud to Bow first towards the bit cente r and then outwards. It was extensively how tested using high-speed photogr aphy to ensure that bit balling was prevented. It includes features to addr ess bit whirl which were demonstrated in full scale laboratory testing to r educe the bit's vibration level. The mechanical design maximizes open-face volume, known to benefit penetration rate, by using very high blades. Howev er, the heights attainable can be limited by the bit body's mechanical stre ngth. Steel was chosen to maximize blade strength and was coated with a new ly developed hardfacing to improve erosion resistance. A program of fatigue testing assured adequate strength.