Rock Breaking Drill Bit Overview

In the mining of coal, oil, natural gas and other mineral resources, as well as various types of geotechnical engineering, the rock breaker drill bit is widely used as an important rock breaking tool. With the increasing demand for energy and the gradual depletion of shallow mineral resources, drilling and mining activities have been gradually transformed to deep, complex and difficult-to-drill formations. This transformation has put forward higher requirements for the performance of rock-breaking drill bits.

According to the classification of cutting teeth materials, rock-breaking drill bits are mainly divided into cemented carbide drill bits and PDC (diamond composite chip) drill bits. Carbide drill bits played an important role in mining in the past, but with the increase in mining difficulty, their performance gradually fails to meet the demand. In contrast, PDC drill bits stand out for their excellent rock-breaking ability, and the market size is increasing year by year.

PDC drill bit and its working principle

PDC drill bit mainly consists of drill bit body, cutting teeth (diamond composite piece), hydraulic structure, retaining surface and joints. Among them, the cutting teeth are the core of PDC drill bit, which are made of diamond composite sheet. Diamond composite piece is a new type of composite superhard material made by sintering diamond micropowder, bonding agent and cemented carbide liner under high temperature and ultra-high pressure, which has extremely high hardness and good toughness.

During the drilling process, the PDC drill bit cuts into the formation with the cutting edge of the cutting teeth through the torque applied by the drilling rig. Due to the high hardness and toughness of the diamond composite, the PDC bit is able to easily cut into the rock interior and maintains a sharp cutting edge for a long period of rock-breaking operations, continuing to work efficiently.

Depending on the manufacturing process and material, PDC drill bits can be categorized into carcass type and steel body type. Carcass type drill bits are made of sintered tungsten carbide powder, which have high rigidity and hardness, are not easy to be damaged and have good diameter preservation effect, but the manufacturing process is relatively complicated. Steel body type drills are made of medium and low carbon alloy steel through machining, which can guarantee the processing quality, but the strength and durability of the drill bit is general.

Rock breaking mechanism of PDC drill bit

The rock breaking mechanism of PDC drill bit mainly includes the following:

Cutting: mainly occurs in softer formations, the cutting teeth of the PDC drill bit go deep into the formation under drilling pressure, and with the rotation of the drill bit, shear force is generated on the formation, thus cutting the formation and forming rock chips.

Crushing: mainly occurs in brittle rock formations, and is unique to PDC drill bits with alternating arrangements of cusped and rounded teeth. The sharp teeth create stress cracks in the formation when they contact it, and the subsequent crenellated teeth cut the formation that has stress cracks, thus improving the breaking efficiency.

Plowing effect: When the round teeth of PDC drill bit cuts the rock, the drilling pressure makes the round cutting teeth form cracks inside the rock, and expand with the deepening of the cutting teeth, which ultimately leads to rock breakage.

Abrasive action: mainly occurs in high hardness, high abrasive stratum. Due to the high density of the ground rock, it is not easy to rupture, the cutting teeth of the PDC drill bit repeatedly cut the ground under the drilling pressure, grinding it into fine granular rock chips. However, this method will accelerate the wear of cutting teeth.

Impact crushing effect: mainly embodied in the PDC composite drill bit. During the drilling process, the vibration generated by the rotation and autorotation of the tooth wheel bit, as well as the vibration formed by the unevenness of the rock at the bottom of the well, causes the cutting teeth of the bit to crush the rock under the dual action of drilling pressure and vibration. This mechanism has higher drilling efficiency and longer service life than ordinary PDC bits.

BN(China) Technology PDC cutting teeth

BN(China) Technology is a high-tech enterprise integrating scientific research, production, sales and service. The company specializes in the research and development and production of diamond composite blades for drilling, and the products mainly include two structural forms of planar and spherical, and have a complete range of models, which can meet the drilling needs of different rock formations. BN(China) Technology has batch large-scale synthesis equipment, which provides a strong guarantee for the consistency and stability of product quality as well as supply ability. Through continuous technological innovation and optimization, BN(China) Technology is committed to providing customers with better quality diamond composite products and more professional technical services.