What Is a PDC Drill Bit? Why Is a PDC Drill Bit So Important?

As drilling technology develops, PDC bits are becoming increasingly popular in the drilling industry, especially in oil and gas drilling. As an important tool for oil drilling, PDC drill bits play a decisive role in the drilling process. Today, we will explore everything you need to know about PDC bits.

What Are PDC bits?

Polycrystalline Diamond Compact bits (PDC bits) are a type of bit used in the drilling industry. PDC bits consist of a fixed bit and several PDC cutters. Since the bit is fixed and contains no moving parts, the bit rotates as a whole. PDC cutters or inserts are made up of a layer of polycrystalline diamond and a tungsten carbide substrate, with the diamond layer bonded to the substrate. This advanced design provides the bit with excellent performance in terms of wear resistance, erosion resistance, and high-temperature tolerance, thus enhancing drilling efficiency and lifespan.

PDC drill bits were first manufactured in 1976. In recent years, PDC bits have been widely used in various applications such as well drilling, mining, and oil and gas drilling.

Types of PDC Bits

There are mainly two types of PDC bits: matrix-body bits and steel-body bits. These two types differ in structure and capabilities. The choice of bit depends on the application requirements.

Matrix-Body PDC Bits

Matrix-body bits are made from a composite material containing tungsten carbide particles and a metallic binder. Due to their hardness and excellent erosion and wear resistance, matrix-body bits are more suitable for drilling hard rocks. However, compared to steel-body bits, matrix-body bits are more brittle and less resistant to impact. Additionally, the heterogeneity of the matrix can affect its physical properties, making its performance less stable than that of steel-body bits.

Steel-Body PDC Bits

Unlike matrix-body bits, steel-body bits are made from high-alloy steel and possess good impact resistance. However, steel-body bits are relatively softer, with poorer erosion and wear resistance, making them more prone to wear. The solution is to apply hardfacing to the steel body to extend its lifespan. Through hardfacing technology, steel-body PDC bits can also achieve considerable durability. Steel-body PDC drill bits are more suitable for drilling soft and sticky formations.

PDC Cutters

PDC cutters are composed of two parts: the diamond table and the tungsten carbide substrate. The diamond table is the diamond layer bonded to the substrate, as previously mentioned. As the hardest material, diamond can cut through any other material, making it an essential component in drilling. In addition to hardness, diamond can efficiently bond with tungsten carbide to form complete cutters, which can be inserted into the bit.

The important raw material for PDC cutters is diamond grit, which are tiny synthetic diamond particles. Synthetic diamonds resemble natural diamonds in every detail, making them sharp, hard, and wear-resistant. Moreover, compared to natural diamonds, synthetic diamonds perform better in terms of shearing. Due to structural reasons, synthetic diamonds have lower stability at high temperatures, so PDC cutters require adequate cooling during drilling.

The diamond table is composed of diamond grit, tungsten carbide, and a metallic binder. These materials are sintered into a diamond-rich layer. The ideal thickness for a diamond table should be between 2mm to 4mm, while the height of the tungsten carbide substrate is usually 0.5 inches.