Effects of the Chamfer on the PDC Cutters

Effects of the chamfer on the PDC cutters

PDC (Polycrystalline diamond compact) cutters play a key role in the performance of PDC bits in oil & gas drilling. It’s very important to study the rock-breaking mechanism for PDC bits to deal with challenging formations, especially when the wells become increasingly longer and more complex.

Among all the factors influencing the cutting efficiency, the chamfer is easy to be ignored in theoretical and experimental studies.

The chamfer is a transitional edge between two faces of an object. The PDC cutters usually have chamfer both on the bottom and diamond layer.

In the mid-1990s, chamfering technology began to be widely used on PDC cutters, and the multi-chamfering technology was adopted in the form of a patent in 1995. If the chamfering technique is applied correctly, the fracture resistance of the cutter during drilling can be improved by 100%. The Baker Hughes company has successfully used a double chamfer technology on the teeth in recent years.

The double-chamfer PDC cutter is a new technology combining a primary chamfer with a secondary edge, enabling greater footage to be drilled without compromising the rate of penetration (ROP).?Since 2013, more than 1, 500 runs with bits utilizing double-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.

Chamfering polycrystalline diamond compact (PDC) cutters have 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

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It was found that smaller angle means faster ROP but more tendency to chipping and cutter damage than large angle. Large angle means more durable cutters but slower ROP. The angle value has to be optimized according to the types of the common formation to be drilled.

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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.