Requirements for cemented carbide in Coalfield Geological Exploration

The cemented carbide cutting tool embedded and welded on the bit body is used as a tool to break rock. This drilling method is what we call cemented carbide drilling. Cemented carbide is the preferred tool material in coalfield geological exploration. Cemented carbide drilling accounts for about 80% of the total quantities in coalfield geological drilling in China. What problems should be paid attention to during drilling? What are the requirements for cemented carbide in coalfield geological exploration? Today we will share with you.

First of all, we should know the nature of rock stratum and select the type of drill bit scientifically and reasonably

Cemented carbide bits are suitable for drilling in soft rock and medium hard rock strata, and are not suitable for drilling in hard rock strata above grade 8. In the process of drilling, we should scientifically and reasonably select efficient bits and optimal drilling procedures according to the rock properties.

When drilling the first kind of soft rock with cemented carbide, the rock is easy to break, the rock abrasiveness is small, and the drilling efficiency is high. However, there are more rock powder and large rock powder particles in the hole, and the hole wall is easy to collapse.

Cemented carbide has certain abrasiveness when drilling the second type of rock, and the key problems to be solved during drilling are roughly the same as those of the first type. Therefore, when drilling argillaceous rock, the frame bit with large cutting depth or too deep edge should be selected.

When cemented carbide is used to drill the third kind of rock, the drilling efficiency is low. To select a variety of stepped crushing bits or a variety of small cutting tool bits.

When drilling the fourth type of rock with cemented carbide, it is characterized by hard rock, high abrasiveness, serious alloy wear and low drilling efficiency. The key to solve the problem in drilling is to improve the drilling efficiency under the condition of prolonging the service life of the bit. If the rock is uneven, we should also pay attention to the problem of alloy edge collapse.

Secondly, strictly abide by the operating procedures during drilling.

Before drilling with cemented carbide, we must strictly check the insert welding quality of the drill bit. Carefully line up the drill bits in groups and grind them in turns to ensure consistent hole diameter.

Be sure to keep the hole bottom clean. When a new bit is lowered into the hole to start drilling, it is necessary to use light pressure, slow rotation, large pump capacity and slow hole sweeping to the end to prevent alloy edge collapse and core blockage from affecting the drilling efficiency of the whole round.

In the process of drilling, if the rock stratum with difficult coring is encountered, such as the core is easy to be washed out and worn, the return length shall be reasonably controlled to ensure the core recovery rate.

There is also the need to reasonably grasp the time for the return footage of cemented carbide bits.

When the artificial sharpening alloy bit is used for drilling, the cutting tools are gradually blunt with the increase of drilling time. Therefore, the mechanical ROP decreases with the increase of drilling time. Scientifically and reasonably grasp the return footage time to make the return drilling speed reach the best value.

Cemented carbide has the advantages of high hardness, strong corrosion resistance, high wear resistance and stable chemical properties, which makes it easier to deal with the harsh coalfield geological exploration environment.