Enhancing Drilling Efficiency with Flanked Non-Planar Shaped PDC Cutters

Abstract

Abstract This paper examines the performance of a novel Flanked Non-Planar (FNP) shaped Polycrystalline Diamond Compact (PDC) cutter through laboratory and field testing in challenging applications. Testing results demonstrate significant advantages of the new cutter shape, which are further validated by an extensive field test program in the Middle East. The geometry of the PDC cutter has emerged as a crucial factor in enhancing fixed-cutter drill bit performance industry-wide. Two types of cutters were investigated: a V-shaped FNP and a non-V-shaped FNP cutter. Both cutters had identical non-planar geometry on the face but varied in cutter-rock interaction characteristics. Field evaluations compared these cutters with legacy cylindrical cutters in terms of drilling efficiency, durability, repairability, and cost per foot. Laboratory tests assessed drilling efficiency at single cutter and full-scale drill bit levels. Field testing involved more than 470 runs across the Middle East, using offset runs with legacy cylindrical cutters for comparison. Laboratory tests revealed significant benefits of FNP cutters. The non-V-shaped FNP cutter reduced vertical force by 20% due to its angled flank, which improved cuttings evacuation and decreased frictional losses. The V-shaped FNP cutter showed a 30% reduction in vertical force and enhanced fracture propagation with its tip geometry. Full-scale tests demonstrated a rate of penetration (ROP) improvement of 13 to 38% for the non-V-shaped FNP drill bit across different formations, while the V-shaped FNP drill bit achieved a 29 to 40% ROP improvement. Field trials in the Middle East across various conditions showed ROP improvements of 14 to 112%, with the highest gains in shales and carbonates using the V-shaped FNP cutter. Cutter durability was comparable to conventional round cutters, considering the interval drilled and dull condition. Moreover, a cost analysis considering bit cost, ROP, and rig rates demonstrated significant reductions in cost per foot compared to offset runs. Overall, the novel FNP cutters offer tangible drilling efficiency gains that significantly reduce drilling costs. This paper highlights the significance of exploring innovative shaped PDC cutter designs and their impact on drilling efficiency. It demonstrates that FNP cutters improve efficiency at both micro and macro levels. Field testing confirms that these novel geometries provide tangible ROP performance and drilling cost reduction without compromising durability or repairability.