What is the difference between PDC Bits and tricone drill bits?

PDC (Polycrystalline Diamond Compact) bits and tricone drill bits are two common types of drill bits used in the oil and gas industry and other drilling applications. Here are the key differences between PDC bits and tricone bits:

Cutting Structure:

The cutting structure is the primary distinction between PDC Drill Bits and tricone bits. PDC bits have cutters made of synthetic polycrystalline diamond materials that are bonded to a tungsten carbide substrate. These diamond cutters grind and shear the rock formations during drilling. Tricone bits, on the other hand, have three rotating cones with teeth or inserts made of hardened steel or tungsten carbide. The cones roll and crush the rock formations to create cuttings.

Cutting Action:

PDC bits primarily achieve cutting through a grinding and shearing action. The diamond cutters on the bit's surface grind and scrape the rock formations, breaking them into small chips or cuttings. Tricone bits rely on the rotation of the cones with teeth or inserts to crush, chip, and scrape the rock as they roll, creating cuttings.

Application:

PDC bits are generally preferred for drilling through hard and abrasive formations, such as shale, limestone, sandstone, and compacted formations. They excel in high-impact and abrasive drilling environments. Tricone bits are more versatile and can be used in a wider range of formations, including soft, medium, and hard formations. They are commonly used in drilling operations where the formations are less abrasive and require a combination of crushing and scraping action.

Durability:

PDC bits are known for their high durability and longer lifespan compared to tricone bits. The diamond cutters on PDC bits are highly wear-resistant and can withstand the harsh drilling conditions encountered in hard formations. Tricone bits, while durable, may experience faster wear due to the rolling and crushing action of the cones.

Cost:

PDC bits tend to be more expensive than tricone bits due to the cost of manufacturing the polycrystalline diamond cutters. Tricone bits with steel teeth are typically more affordable, while those with tungsten carbide inserts are generally more expensive.

The choice between PDC bits and tricone bits depends on various factors, such as the formation characteristics, drilling objectives, drilling parameters, and cost considerations. Drillers evaluate these factors to determine the most suitable bit for a particular drilling operation.