A quick guide to understanding the drill bits and PDC cutters

1.?????Drill bits

As we all know that drill bits are used for well drilling. Well drilling is the process of drilling a hole in the ground for the extraction of a natural resource such as ground water, brine, natural gas, or petroleum.

Drilling to explore the nature of the material underground (for instance in search of metallic ore) is best described as borehole drilling.

?Types of drill bit

?Drill bits are usually grouped into two categories: roller cone bits and fixed-cutter bits.

Roller cone bits can be further divided into two categories: milled-tooth and insert, and are designed to drill rocks of various types and strengths. While the milled-tooth bits are generally used when tooth wear is not a critical issue, the insert bits with tungsten carbide inserts are used when tooth wear becomes the limiting factor in the life of the bit. Both these types of roller cone bits have bearings that limit their operating lives. If we talk about the rock-cutting mechanism, roller cone bits use a shoveling action in soft formations and a crushing action in hard formations.

?Fixed cutter bits can also be categorized into two types: polycrystalline diamond cutters (PDCs) and diamond matrix bodies. The major points of difference between roller cone bits and fixed-cutter bits are the rock-cutting mechanisms and a lack of bearings. While the PDC bits cutting mechanism is rock shearing, the diamond matrix is rock grinding. The former is used in all non-abrasive rocks regardless of strength, whereas the latter is generally used in extremely hard abrasive formations.

?Drill bit selection is usually based on past bit performance records. Past experience and learning are key factors in selecting the right bit for the right hole interval to be drilled.

2.?????PDC cutters

?PDC（Polycrystalline Diamond Compact ) cutters are sintered with selected diamond powder and tungsten carbide under high temperature and ultra-high pressure.

?PDC has high hardness, wear resistance, and impact resistance, which are widely used for oil/gas well drill bit, rock drills and coal mining bits also could be used for diamond tools for cutting, grinding, and polishing.

Sizes and shapes of PDC cutters

As a general rule, large cutters (19mm to 25mm) are more aggressive than small cutters. Smaller cutters (8mm, 10mm, 13mm, and 16mm) have been shown to drill at higher ROP than large cutters in certain applications. One such application is limestone for example.

?PDC cutters come in many sizes, shapes, and forms. The most common shape is the cylindrical planar type, there are also shaped PDC cutters, like PDC dome buttons, PDC conical buttons, PDC parabolic buttons, and other irregular shapes.

A PDC cutter consists of two parts, the diamond table, and the substrate. The thin disc at the top is the diamond, responsible for removing the rock. Diamond is one of the hardest materials on earth. The larger portion of the PDC cutter is the metal tungsten carbide alloy responsible for securing the cutter to the drill bit.

Production of PDC cutter

In order to make a PDC cutter, diamond grit is placed in a small metal cup placed in a press.

The most common press machine is called a cubic press. The cubic press uses 6 anvils which converge to create pressures higher than 1,000,000 PSI, but this pressure alone is not enough to create a diamond. As the diamond is pressed, it is also heated to 2300 degrees Celsius. A catalyst is added before pressing to help speed up the process. The catalyst is usually cobalt. The diamond will sit in this heated and pressed state for several minutes, whilst diamond-to-diamond bonds are created.

ZZbetter has been in line of PDC cutter for several years now. We innovate to make sure every PDC cutter is crafted for your use and requirement to perfection by our experienced professionals.

Learn more about us by browsing through the website.www.zzbetter.com

For samples of PDC cutter, please contact us at [email protected].