As a tool for drilling rock formations, rock bits have been widely used. Significant improvements in bit performance have directly reduced drilling costs, especially in the past decade. Service life and drilling speed are two performance indicators, which ultimately determine the extent to which the drill bit affects the drilling cost. Increasing the drill bit's ROP and service life is an effective way to reduce drilling costs. Data has proven that the improvement of the drill rate has a greater impact on the reduction of drilling costs than the improvement of the bit life. The improvement of the drill bit cutting structure is to improve the drill bit's machinery. The most direct method of drilling speed. For a long time, people's improvements to the cutting structure have mainly focused on the main cutting tooth structure. For example, in the cemented carbide tooth structure, people have invented wedge-shaped teeth, spoon-shaped teeth, partial-top spoon-shaped teeth, and other wear teeth.
In the past ten years, people have gradually realized that the gauge structure also has a greater impact on the drill bit's ROP and life. Especially the drill bits used in highly deviated wells and horizontal wells require a reasonable gauge structure. Many new gauge structures have been researched and developed and applied to rock bits with good results.
1. The use of high-strength and high-toughness alloy teeth improves the ability of the teeth to resist impact and reduces the probability of tooth breakage. The soft ground inserts the top spoon-shaped teeth.
2. The bearing of the tooth palm is covered with a layer of hard alloy, and the roller bearing is silver-plated, so that the bearing has improved anti-seize and load-bearing capacity.
3. The O-shaped sealing ring adopts more wear-resistant and highly saturated nitrile rubber, which increases the cross-section of the sealing ring, and adds a small sealing boss at the outer end of the sealing area, which improves the reliability of the sealing;
4. Using the steel ball locking roller, it can be suitable for relatively high speed.
5. The use of newly produced grease that can withstand temperatures of 250°C and has low wear improves the high temperature resistance of the drill.
6. The optimized number of teeth and the equipment such as tooth-exposure plus alloy teeth can maximize the cutting and speed of the drill.