Introduction to the Structure of PDC Drill Bit

PDC drill bit relies on the cutting teeth installed on the drill bit body to cut through the formation. These cutting teeth have two structures: the compound sheet cutting teeth and the columnar teeth. Their structures and installation methods on the drill bit vary. Compound sheet cutting teeth are formed by directly welding the composite sheet into the grooves reserved on the drill bit body. It is generally used for body drill bits. Columnar cutting teeth are formed by welding the composite sheet onto the tungsten carbide column and then embedding or welding the teeth into the holes on the drill bit body. It is generally used for steel body drill bits and also for somebody's drill bits. Click for PDC drill bits manufacturers.

Poly-crystalline diamond composite sheets have two types: columnar and sheet. They come in shapes such as circles, pointed and semi-circles, and are usually embedded in body drill bits in columnar form.

The arrangement of the PDC drill bit cutting teeth

The arrangement of cutting teeth is related to the formation being drilled and the type of drill bit used, which affects the mechanical drilling speed, total footage, and wear of the drill bit. The more cutting teeth are arranged, the slower the wear, and the longer the drill bit life. However, the mechanical drilling speed is lower. The arrangement of cutting teeth should ensure that the cutting force, the amount of rock cut, the load, the torque, the wear, and the hydraulic cleaning of each cutting tooth are the same, so equal cutting, equal power, and equal wear design requirements are necessary.

The edge angle of the PDC drill bit cutting teeth and the body

Refers to the distance between the cutting edge and the drill bit body. The cutting teeth can be fully extended or partially extended: full extension is generally used for drilling soft formations, and full extension cutting teeth are beneficial for drill bit cleaning, and the drilling speed is higher; partial extension is used for hard formations. It has higher cutting tooth strength, but cleaning the PDC drill bit is relatively difficult, and it is suitable for drilling in oil-based drilling fluids; hard alloy body drill bits are formed by casting and are not limited by processing.

The arrangement direction of cutting teeth

At present, there are many studies on the arrangement of cutting teeth on PDC drill bits. In order to facilitate clearing and drilling, the arrangement of cutting teeth on the drill bit body should also pay attention to the inclination angle and the back inclination angle. The inclination angle produces a push-out force during drilling and, under the cleaning action of drilling fluid, the inclination angle can assist in ejecting rock debris from the center of the drill bit and effectively clean the PDC drill bit.

The back inclination angle is not only beneficial for cleaning the cutting teeth of the PDC drill bit but also can reduce the vibration of the cutting teeth when the cutting force is increased in hard rock formations, which is conducive to protecting the cutting edge and prolonging its life. The back inclination angle is generally 0-25°. The greater the back inclination angle, the lower the mechanical drilling speed, but in hard formations, the back inclination angle can reduce damage to the cutting edge.

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