Innovative Dual-Chamfer Edge Technology Leads to Performance Gains in PDC Bits

Abstract

The dual-chamfer diamond cutter is a new technology combining a primary chamfer with a secondary edge, enabling greater footage to be drilled without compromising rate of penetration (ROP). The average distance drilled in the Mississippi Lime formation was increased by 40% while maintaining comparable ROP to offsets and with significantly improved dull bit conditions, resulting in greater reliability. Since 2013, more than 1, 500 runs with bits utilizing dual-chamfer technology were performed in Oklahoma. The dull state was significantly improved, resulting in reduced incidence of ring outs, core outs and other deleterious bit damage. The data presented in this paper are based on over 130 laboratory drilling tests. Chip flow analysis was conducted using a unique visual pressurized single-cutter test machine. Full-bit testing was carried out in a pressurized drilling simulator to compare drilling performance. Cutter wear life testing was conducted using an aggressive granite wear test protocol where a 100 to 200% increase in cutter life was documented by edge geometry changes. Chamfering polycrystalline diamond compact (PDC) cutters has a significant positive effect on edge durability and overall longevity. This concept has not changed over several decades since the introduction of chamfered PDC cutters. Many investigations were conducted with either a singular change to the chamfer height or chamfer angle or with combined edge geometries. These investigations, however, showed only limited success. The new geometry is based on a thorough understanding of historic investigations and failures observed on how diamond cutter wear flats are formed and degrade. Developments in the drilling sector with greater use of high-power directional motors results in more intermittent off-center drilling with high cutter edge loading. In addition, cutter developments now use leaching methods to reduce cutter wear and better control thermal cyclic loading. A leached diamond layer makes diamond cutters more susceptible to impact damage, resulting in greater premature and catastrophic failures. For the customer, the improved cutter technology resulted in significant cost savings and more confidence in tool life, enabling greater endurance and durability. Ultimately, the new cutter technology enables lower drilling costs and opens more drilling frontiers that were previously unprofitable.

Unique Hybrid Drill Bit with Novel PDC Cutters Improves Performance in Ultra-Deepwater Brazil Pre-Salt Application

“…A series of field tests in the Mississippi Lime application in Oklahoma showed bits with dual-chamfer cutters increased the average meterage by 40% while maintaining a comparable average ROP (Izbinski, 2015). A series of field tests in the Mississippi Lime application in Oklahoma showed bits with dual-chamfer cutters increased the average meterage by 40% while maintaining a comparable average ROP (Izbinski, 2015).…”

Performance dynamics of pdc cutters used in breaking ductile brittle rock

“…However, the estimation proceeding from a large number of assumptions is very tentative. A more precise estimate is provided by the results of bench-scale tests conducted to reproduce the rock breaking process and perform correct measurements (Besson et al, 2000;Borisov, 2002Borisov, , 2010Glowka, 1987;Izbinski et al, 2015;Rafatian et al, 2010;Rajabov, 2012). However, these works pay almost no attention to the dynamic component of cutter loads.…”

Vibration failure and anti-vibration analysis of an annular-grooved PDC bit

“…Polycrystalline diamond compact (PDC) bits break rock via shearing and offer many advantages for drilling, such as high efficiency in rock breaking, enhanced safety (e.g., no moving cutting elements), and long cutting life thanks to PDC teeth wear. Given these benefits, PDC bits are widely used in oil and gas well drilling [1][2][3] , and researchers have conducted extensive work on the improvement of drilling speed focusing on two main aspects: (1) how to improve bit's performance to feed into the formation, e.g., the development of a new cutting-teeth structure or combinations of various rock-breaking methods; and (2) the matched use of drilling tools, drill bits, and downhole tools, e.g., screw drill, turbodrill, axial impactor, peripheral impactor, or hydraulic oscillator. To deliver efficient drilling, drill bits require aggression and a long service life.…”

“…Such stability is thus essential to consider in bit design. Existing methods to improve PDC bit stability include the following: (1) adjusting PDC teeth parameters to ensure that the unbalanced bit force is less than 5% of the weight on bit (WOB); (2) optimizing the shape of the drill bit's crown contour and increasing the angle of the inner cone to help to prevent transverse vibration to some extent; (3) setting the PDC teeth to form grooves at the bottom of the hole, which can suppress bit vibration; (4) using a spiral blade, dispersing the cutting force directed at the shaft wall, and reducing contact stress between the bit-retaining part and the shaft wall; and (5) improving the impact resistance of PDC teeth by improving their processing technology [6][7][8][9][10] .…”