Nevada geothermal wells are drilled through exceptionally hard, abrasive, and highly fractured volcanic, metamorphic, and crystalline formations. These conditions generate low ROP, severe drilling vibrations, accelerated drill bit cutter wear, and frequent drilling dysfunctions. For geothermal operators, the challenge is to maintain wellbore quality and directional control while drilling faster and farther in high-temperature environments where drilling performance directly impacts project economics.
To reduce well construction costs and improve operational efficiency, the operator sought drill bit technologies capable of increasing ROP, extending bit life, suppressing whirl and other drilling vibrations, and maintaining stable performance under elevated geothermal temperatures. Previous attempts using roller cone and PDC bit designs resulted in multiple bit runs to complete the 12.25-in reservoir section, leading to increased downtime and higher costs. The operator needed a reliable drill bit solution to drill the entire section efficiently, with fewer bit trips and higher penetration rates.
To overcome the hard, abrasive, and highly heterogeneous geothermal formations encountered in Nevada, the operator selected the 12.25-in AxeBlade bit equipped with the StingBlade diamond element. The AxeBlade bit profile promotes efficient rock failure by reducing the energy required to break hard crystalline and volcanic formations, while the StingBlade diamond element initiates localized fractures ahead of the primary cutters. This combination improves depth of cut and reduces drilling inefficiencies commonly associated with hard-rock drilling, suppressing vibration-related dysfunctions, and maintaining cutter sharpness.
The AxeBlade bit and StingBlade diamond element successfully drilled the target interval in a single run, delivering an average ROP of 54 ft/h—a 160% improvement over the average ROP achieved in offset wells. The bit drilled seven times farther than the average footage per run of the closest offset wells, demonstrating exceptional durability in Nevada's hard and abrasive geothermal formations. By completing the section in one run instead of the seven bit runs required in offset wells, the AxeBlade bit substantially reduced trip-related time, improved operational efficiency, and helped lower overall well construction costs.
