A new edge preparation of Polycrystalline Diamond Compact (PDC) cutters has been developed to target applications where either weight or torque is limited. This paper describes the geometry, which differs considerably from existing thermostable product.
Initial testing at atmospheric conditions in a drilling laboratory shows a 30% reduction in torque and a 100% increase in penetration rate when compared to conventional cutter geometry. Secondary testing was conducted with drill bit designs at a non-commercial test facility. In this controlled environment, designs with new cutter edge geometry were compared directly to those with conventional cutters. By using the same drill bit cutting structure and parameters, any difference in torque and penetration rate was solely dependent upon the cutter geometry. Additionally, to quantify any effects caused by torsional or lateral vibration, a downhole dynamics recorder was used to gather data at a high frequency sample rate.
Performance studies are presented for a variety of applications from around the world but focusing on applications within the US Rockies. They compare direct offset runs against conventional geometry cutter designs. Results demonstrate that the new geometry delivers footage and ROP equal or greater than the best field offsets.
The increased penetration rate and reduced torque provided by this geometry result from more efficient failure of the rock. This provides reduced Mechanical Specific Energy and improved drilling efficiency, thus reducing drilling costs for the operator. This is a significant step change in PDC cutter technology, dramatically increasing fixed cutter drill bit performance.