New understandings of the applications of PDC cutters in oil and gas drilling

Abstract

Today, the polycrystalline diamond compact (PDC) cutters have already reached a pretty high level of quality and are still keeping advancing. The formations drillability is positively related to the quality of PDC cutters. With advances in PDC cutters, most formations have become easy-to-drill. Years of improvements in the PDC cutter quality and the drilling techniques have also upended some long-hold knowledge and understandings about the cutter applications. PDC designs abandoned long ago are once again applicable, such as unleached, thin diamond table, small chamfer, and non-pure diamond mix. From the perspective of saving money and environmental protection, these long-abandoned PDC designs are worth a shot, but are suggested to be used in the well-understood formations and lithologies. On the other hand, why do PDC cutters always perform poorly in challenging formations? The results revealed that this is mainly due to the irregular dynamic impacts and inefficient rock cutting, which are the primary causes of the premature failure of PDC cutters and bits. The challenging formations as well as the unknown formations in the exploratory wells still prefer the cutters with the best quality, such as pure diamond mix, thicker diamond table, deep leaching, excellent residual stress management, and the ones from the best manufacturer. In addition, how to select the right cutters depends highly on the bit failure forensics and the multi-index evaluation. The emphasis of cutter selection is on selecting the right design and the right materials for the right formations, rather than the most expensive ones.