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What is DTH drilling method?

Views:6     Author:Site Editor     Publish Time: 2020-03-31      Origin:Site

The DTH hammer is probably the most important component on the rig, and the DTH hammer system has many advantages over other methods, it is a good choice for fragile rock or for large diameter holes . But, for hard rock or where small diameter holes are needed, the top hammer drill system can achieve satisfactory results. So far, the DTH system is the most extensive way, it can be used very successfully in various ground conditions from soft, medium to hard. So we need to know more about its usage.


This article contains the following aspects:

  • The introduction of DTH hammer

  • What is DTH drilling method

  • Conclusion

1.Introduction of DTH hammer

When you need a high-quality hole with a diameter between 100-254 mm, DTH (Down Hole) drilling is by far the best and most effective method. DTH drilling can be performed on most types of rock, whether hard or soft. It is a method commonly used in the mining, well drilling, construction,  oil and gas industries.

In DTH drilling, the drill string rotates while the hammer continuously hits the rock downwards. Inside the DTH hammer, piston driven by compressed air gives the drill its amazing power. Rocks are crushed in a very effective way by combining with rotational motion.

DTH drilling is the fastest and most effective method of drilling in hard rock. This is bad for cohesive soil or unconsolidated overburden deposits, but it doesn't matter if you only go through these depths (up to 30 meters deep) into deeper holes in the bedrock formation.

2.What is DTH drilling method?

First, the compressed gas enters the DTH hammer through the drill pipe, and then is discharged from the button bit of the DTH hammer. The rotary motion of the down-the-hole hammer is provided by the rotary hammer, and the thrust of the shaft is provided by the propeller, which is transmitted to the DTH hammer through the drill pipe. The brazing layer is mainly used to transmit thrust and rotary motion to the drill. The snap ring controls the axial movement of the drill bit, and the check valve is used to prevent ballast and other impurities from entering the DTH hammer when the pressure supply is stopped. During drilling, the DTH hammer pushes the position of the diving hole button to the brazing sleeve. At this time, the piston directly hits the drill bit to drill the hole. When the rig rises from the bottom of the well, it starts to explode violently.

There are many casing systems, ranging in size from less than 100 mm to more than 1000 mm, depending on the type and purpose of the hole to be drilled. For wells, always adjust the diameter of the casing and well bore to accommodate the required installation of pump and well bore lining.If the customer only needs a small water hole with a diameter of 4 to 6 (100 mm to 150 mm), it can accommodate 3.5 to 5 drill liner and well screen pumps. 3 inch pumps, producing up to 4000 liters per hour. 4 inch pumps, producing up to 16,000 liters per hour. This includes most private water supplies. For larger farm irrigation wells and industrial or municipal water supply in excess of 16,000 liters / hour, you need to drill 7 wells with diameters "to 12" to accommodate 6 inch or 8 inch pumps with proper lining. Sometimes it is better to drill a small diameter exploration hole, use a large amount of water to test the presence of water without any cost, and then, if you find it, drill a larger diameter hole. Generally, doubling the diameter will produce twice the output (this is proportional to the internal surface area of the borehole). If you want to install a system for all wells, we find that for most boreholes, usually at depths of 30 to 120 meters, they prefer a diameter of 8 inches (200 mm) to allow the production large enough, Install any size lining (6.5 inches) and gravel filter packaging, The output of 4 inch or 6 inch pump is up to 75,000 liters per hour. If you are buying a drill, you need to match the capacity of the drill to the size and depth of the hole. If you plan to drill, you also need to match the capacity and pressure of the compressor. Measure the planned drilling depth and diameter.

 Drilling is usually several hundred meters higher than digging. The live pump drilling usually use in rural or sparsely populated areas. Most shallow rigs are mounted on large trucks, trailers or tracked vehicles. The depth of a well is usually between 3 and 18 meters, but in some areas it may exceed 900 meters. The segmented steel drill string of a rotary drilling rig is usually composed of 6 meter long galvanized steel pipes threaded together. It is equipped with a drill bit or other drilling equipment. The bottom of the rotary rig is designed to fit the steel casing to the well combined with actual drilling. During DTH drilling, air or water is used as a circulating fluid instead of cuttings and cooling the drill bit. Another form of rotary drilling is called mud rotary drilling, which needs to continuously change the mud or drilling fluid during the drilling process so that it can be drilled. Regardless of whether there is a casing in the well, sufficient water pressure must be maintained to keep the well wall unblocked. In general, no matter what mechanical equipment is used, the borehole of solid rock can only be drilled after the DTH drilling process is completed.

3. Conclusion

The use of DTH hammer must be strictly in accordance with its use method, pay attention to choose the appropriate size. The DTH hammer produced by our company is the leader in this industry and is used in all aspects of society. So we are confident to provide you with the highest quality products.



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