ROP Improvement in Hard Formation Drilling Using Large Size PDC Cutters

ABSTRACT: With the ongoing development of oil and gas drilling equipment, the weight on bit, torque, and hydraulic energy in shallow formations are now sufficient for conventional bits. The study shows that under sufficient energy supply, optimizing PDC bits with larger-diameter cutters can significantly enhance the rate of penetration. To validate this design, cutters with diameters of Φ16 mm, Φ19 mm, and Φ22 mm were tested for rock-cutting efficiency, residual stress, wear resistance, and impact resistance, followed by full-scale bit drilling simulations and field tests at Shengli Oilfield. Results show that larger-diameter PDC cutter offer the fastest rock-breaking speed but at the cost of higher energy consumption. Larger-diameter cutters increase residual compressive stress, improve resistance to external impacts, and, despite a larger wear volume, exhibit smaller wear areas, thereby reducing overall rock-breaking energy consumption after wear. However, lower cutter density reduces drilling stability, potentially leading to bit damage. While large-cutter designs show promising potential for accelerating shallow drilling, energy limitations could affect their performance at greater depths. Overall, this optimized design demonstrates strong potential for enhancing ROP in shallow formations.