Introduction to knowledge about tricone drill bits!

1. Historical Development of Tricone Drill Bits

In oil drilling operations, tricone drill bits are the most commonly used type of drill bit that can adapt to various formations.

In 1909, the world's first roller cone drill bit was invented.

In 1925, the self-activating roller cone drill bit was developed, which solved the problem of cuttings accumulating between teeth and causing mud cake in soft formations.

In 1933, the tricone drill bit with rolling bearings was invented.

In 1935, the tooth axis drill bit was further improved, and the movable-axis tricone drill bit was developed.

In 1949, jet drilling began to be developed and soon applied to roller cone drill bits.

In 1951, drill bits with hard alloy inserts were used, which improved the service life and drilling speed of the drill bits in extremely hard formations.

In 1960, the sealed lubricated bearing was successfully developed, which increased the working time of the drill bits to 40-60 hours and improved the drilling footage by 50%."

2.Motion of Three-cone Bit at the Bottom of the Well

The motion and force status of the cone bit at the bottom of the well are quite complex when it is working. To understand the working principle of the bit in breaking rock, it is necessary to first understand the motion law of the bit at the bottom of the well.

To facilitate the theoretical analysis of the motion law of the cone bit, the following assumptions are made before the analysis:

  1. The bottom of the well and the bit are both rigid.

  2. The pressure on the generatrix of the cone in contact with the bottom of the well is uniformly distributed.

  3. The bit and the cone are rotating at an equal angular velocity.

3.The Impact and crushing effect of the tricone bit

During the working process of the tricone bit like tci tricone drill bits, the teeth of the bit generate impact and crushing on the rock through the bit resonance, which is the main way of breaking the rock by the tricone bit.

As a pdc bit company, when drilling, the bit resonates at the bottom of the well, causing the drilling string to compress and stretch continuously. The lower part of the drilling string transmits this periodic elastic deformation energy to the teeth, which is the source of the impact and pressure of the teeth when the bit breaks the rock.

4.Shearing action of Three-Cone Bit Teeth on Formation

In order to improve the efficiency of the Three-Cone Bit in breaking rocks, it is required to have a certain shearing action on the medium-hard and soft formations in addition to the teeth producing crushing and impact. The shearing action is mainly achieved by the relative sliding between the wheel teeth and the rock while the wheel is rolling at the bottom of the well. In actual work, there are three reasons for the sliding: over-gauge, conical section, and movable axis.

  1. Sliding caused by over-gauge

The tangential sliding caused by the over-gauge of the wheel teeth, and the sliding velocity is proportional to the over-gauge distance. On both sides of the pure rolling point, the sliding direction is opposite.

  1. Sliding caused by conical section

The conical section of the wheel includes the main cone and the sub cone. Although the main cone of the conical wheel coincides with the center of the Three-Cone Bit, the top of the sub cone (extension line) must be over-gauge. Similarly, over-gauge will cause sliding.

  1. Sliding caused by movable axis

We have tricone drill bit for sale. The axial sliding caused by the movable axis can shear the rock between the tooth circles. Although the sliding of the teeth can shear the rock at the bottom of the well to improve the crushing efficiency, it also increases the wear of the teeth.