Innovative Placement of 3D Shaped Cutters for Hard and Abrasive Formations

Abstract

Current well designs that aim to efficiently drill long heterogeneous wellbore sections in a single run make cutter wear mitigation and overall performance increasingly important. However, in these harsh conditions, the durability of PDC bits and their high rate of penetration (ROP) in many formations are often compromised by cutter damage, limiting total footage and penetration rates. These limitations frequently necessitate using multiple bits to complete the section, increasing the overall cost for operators to drill to Total Depth (TD). Therefore, mitigating PDC cutter wear while improving indentation and shearing action, especially in hard rock formations, is crucial for the effective application of PDC technology in modern wellbores. To address these issues, a Bit company has developed a new generation of tools with an innovative cutter arrangement and specific cutter shapes. These bits pre-fracture the rock before shearing begins, achieving higher ROPs and more stable boreholes, particularly in hard rock formations. The PDC bit designs presented in this paper result from extensive research aimed at overcoming historical performance challenges in long, hard, and interbedded formations. The design configuration combines multiple rows of cutters with different geometries. Cutters with force-concentrating tip profiles initially weaken and fracture the rock, followed by another set of specially shaped cutters that shear the weakened rock more efficiently.