A Customized Method of Drill Bit Cutter Layout to Extend Bit Life in Motorized RSS Horizontal Applications

Abstract Horizontal drilling in Kuwait's Mauddud-G formation demands durable, high-efficiency bit designs. This paper presents the first application of BESTE's 6.125-in T613 PDC bit with motorized RSS, engineered with optimized efficient cutter layout cutting structure. The objective is to demonstrate how advanced cutter layout, depth-of-cut (DOC) control, and CFD-driven nozzle placement deliver superior ROP, stability, and cost efficiency without compromising bit integrity. The customization of a 6.125-in. PDC bit started with ensuring an efficient design to endure drilling the challenging lithology and providing a stable tool face at the same time, especially given the expected torsional vibrations. Based on cases in the Kuwait where a matrix 6-bladed body was considered as a reference to improve the profile and cutter layout. The new solution kept the 13mm primary cutting structure, adjusting spacing and the back rake scheme. The layout followed a balancing strategy to reduce time and magnitude imbalance upon transitions, having an even distribution of cutting force as the bit enters a different rock strength formation. Additional critical aspects were modified, such as only 3 nozzles to increase the jet impact force, as well as adding impact arrestors. The bit was paired with a motorized RSS BHA to drill the lateral interval. Real-time parameter management ensured steady toolface control and borehole quality while leveraging the bit's design advantages. The run achieved a step-change in performance: 2,704 ft drilled from 8,120 to 10,824 ft in one run at an average ROP of 90.4 ft/hr, setting a new benchmark in the field. Cost per foot dropped to $6.18/ft compared to $8.63/ft offsets, a 28% reduction. The bit exited with excellent dull grade 1-1-WT-A-X-I-NO-TD, validating durability and rerun potential. CFD-optimized hydraulics improved hole cleaning and cutter cooling, while the DOC-controlled layout maintained efficient rock engagement. These results confirm that modern PDC design principles combined with RSS technology can substantially improve drilling efficiency and economics. This project marked a milestone in drilling innovation with strong support of the Kuwait Oil Company (KOC) Team, who endorsed this run performance. The T613 is the first BESTE bit applied with motorized RSS in Kuwait's Mauddud-G laterals, delivering the highest ROP, contributing to 15% of the Drilling Rate Improvement and the lowest cost per foot in the Sabriyah Field in 6.125-inch section, solidifying its status as a best-in-class solution, demonstrating how innovative technology and collaboration drive measurable efficiency gains in challenging drilling environments.