Since the first roller cone bit was invented in 1909, it has become widely used worldwide. The tricone bit is currently the most commonly used in rotary drilling operations. This bit type has various tooth designs and bearing types, allowing it to adapt to geological formations. By selecting the right tricone bit structure based on the formation being drilled, you can achieve satisfactory drilling speeds and bit penetration rates.​​​​​​​​​​​​​

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A tricone bit consists of three cone-shaped rollers, with the bit body welded together and threaded at the top for connection. The rollers are made of metal with teeth, and the bit is categorized into two types based on tooth design: milled teeth (steel teeth) and insert teeth (tungsten carbide teeth). Milled teeth are suitable for soft to medium-hard formations and are more affordable, while insert teeth are made of extremely hard tungsten carbide, which makes them more expensive but suitable for harder, more complex formations.

Coring bits are specifically designed to extract formation samples during drilling. Their unique design allows them to retrieve intact core samples, which are essential for oil and gas exploration. Geologists analyze these core samples to evaluate the lithology, porosity, and permeability of subsurface reservoirs, helping to determine the amount and recoverability of oil and gas. Coring bits are typically used during the exploration phase, especially in unknown or under-evaluated reservoirs. By using coring bits, drilling teams can obtain accurate geological data to support further development.

Hybrid drill bits are a relatively recent innovation in the drilling industry, developed to overcome the limitations of traditional bit types when operating in complex or interbedded formations. While the concept of integrating multiple cutting mechanisms has been explored for decades, the first commercially viable hybrid drill bit was introduced by Baker Hughes in 2011 with the launch of the Kymera™ hybrid drill bit.​​​​​​​​​​

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A typical hybrid bit integrates multiple cutting elements, including diamond composites, roller cones, and PDC (polycrystalline diamond compact) cutters. Each component is selected for its specific strengths: roller cones provide superior impact resistance in hard or fractured formations; PDC cutters deliver high drilling speed and improved directional control in softer to medium formations; and diamond-enhanced materials increase durability and wear resistance, particularly in abrasive geological conditions

Bi-center bits are an innovative type of bit designed for hole enlargement during drilling. Their design allows them to expand the borehole diameter without increasing the initial hole size, reducing the need for traditional reaming tools. Bi-center bits are particularly suitable for formations that require transitions from smaller to larger diameters, making them ideal for projects that involve multiple hole diameter changes. By reducing the number of bit changes and reaming tool usage, bi-center bits improve operational efficiency and lower overall costs. They are especially effective in complex drilling operations requiring flexible wellbore designs.

PDC bits, short for polycrystalline diamond compact bits, are also known as synthetic diamond bits or composite cutter bits. Since General Electric introduced the first PDC bit in 1973, these bits have become widely used in oil drilling due to their high speed, long life, and high penetration rates. Almost all bit manufacturers have adopted this technology, producing their own series of PDC bits.

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Based on manufacturing processes and structure, PDC bits can be divided into two types: steel-body PDC bits and matrix-body PDC bits.​​​​​​​​​​​​​

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Steel body PDC bits are made from medium-carbon steel and manufactured through mechanical processes. PDC cutters are tightly pressed into pre-drilled holes in the bit body, with the crown surface hardened (e.g., with a tungsten carbide wear-resistant layer) to enhance durability. While these bits are simple to manufacture, their downside is the lower erosion resistance of the bit body, making it difficult to secure the cutters. As a result, they are less commonly used.

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Matrix-body PDC bits feature a steel upper section and a wear-resistant tungsten carbide lower section, formed using powder metallurgy. PDC cutters are brazed into pre-formed slots in the matrix using low-temperature solder. The matrix’s high hardness and erosion resistance give these bits a longer life and higher penetration rates, making them more commonly used today. 

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Natural diamond is the hardest and most wear-resistant material known to humans, making diamond bits ideal for hard and abrasive formations, allowing for higher penetration rates. Despite being expensive, the longevity and penetration capabilities of diamond bits make them competitive in today’s oil drilling industry. Any drill bit that incorporates natural diamonds into its surface or matrix can be categorized as a natural diamond bit.

Full-hole bits are designed for drilling large-diameter wellbores. When larger well diameters are needed, full-hole bits can drill these in a single pass without requiring multiple reaming operations. These bits are often used in unconventional oil and gas wells, underground storage wells, and natural gas wells. Their main advantage lies in their ability to efficiently drill large-diameter holes, reducing the need for multiple-bit changes. For projects requiring large well diameters, full-hole bits are an ideal choice.