From Design Innovation to Field Success: Transforming Well Performance with a Game-Changing Two-Cone Hybrid Bit Design

Abstract This study evaluates the development and implementation of an innovative 16-inch two-cone hybrid drill bit design with the latest generation of tungsten carbide insert (TCI) and polycrystalline diamond compacts (PDC), in a major oil field in the Middle East region. The objective was to improve drilling efficiency and overcome operational challenges in heterogeneous formations, including limestone and interbedded shale sections, with the potential for loss of circulation and wellbore instability. The new Hybrid bit was designed to address issues such as bit balling, low hydraulic performance and erosion observed in previous design iterations. In Addition to improve the overall drilling efficiency and performance. The improved hybrid drill bit incorporated several key design features to target improving the overall performance and elimination an extra trip due to the challenges mentioned above. These include reducing the number of cones from three to two on a six-blade base design for a more aggressive cutting structure and improved drilling efficiency, through detailed finite element analysis to validate the structural integrity of the bit under high-stress drilling conditions. Extensive computational fluid dynamics analysis was also carried out to optimize the number of bit nozzles and maximize the junk slot area to improve bit face cleaning, cuttings evacuation and enhance hydraulic power per square inch to address bit balling issues in shale formations. In addition, the new bit combined dual chamfer 19mm PDC cutters for improved durability and cutting efficiency and features up drill cutters on all blades for improved tripping performance. Furthermore, a comprehensive pre-job analysis roadmap was carried out to tailor the drilling parameters to the specific formations encountered to ensure optimum bit performance. The application of the new 16-inch hybrid drill bit demonstrated exceptional performance improvements across multiple metrics compared to previous bit designs. Specifically, the bit successfully drilled the entire section in a single run, eliminating the need for dedicated clean-out runs previously required due to challenges such as PDC damage in the interbedded formations and reaching the bit revolution limit on the TCI bearing due to the high hours of drilling especially with the low ROP of TCIs. Seal and bearing performance exceeded expectations, achieving 376 krevs while maintaining the structural integrity of the bit. The improved hydraulic design proved particularly effective in managing bit balling issues in such challenging formations. The bit also achieved the highest rate of penetration (ROP) in the field for a rotary assembly, averaging 52.6 feet per hour, a 67% improvement over the average field performance. In addition, the bit was recovered in green condition, indicating minimal wear and highlighting its robust design. These results clearly demonstrate the new hybrid bit design ability to improve drilling efficiency and reduce operating costs by eliminating trips and maximizing ROP. The new hybrid bit's innovative design features, including reduced cone count, optimized hydraulic design and advanced cutter technology, contributed to its exceptional performance, and represents a significant advancement in hybrid bit technology. The success of this application demonstrates the novelty of the new hybrid bit design and its potential to improve drilling operations in heterogeneous formations. The design's success in achieving significant performance improvements while maintaining structural integrity sets a new benchmark for hybrid bit designs in oil well applications.