Drill pipes are known as the most important drilling accessories. Drilling fluid is pumped through the rotary drills as well as the holes in the bit. DTH drills are nothing but a small jack hammer that screws on the bottom of a drill string.
Down-the-hole also known as DTH drilling method has gained a lot of popularity because of its utility in various application segments. The name was originally generated from the fact that it will help to drill large-diameter holes located downwards in surface-drilling applications. DTH method is to drill underground but the overall direction while drilling is upwards instead of downwards.
DTH drill is nothing but a small jack hammer that screws on the bottom of a drill string. It has the ability to break the hard rock into small flakes and dust through its fast hammer actions. This is considered to be the best way to drill hard rock. The key features of DTH drilling comprises of good hole cleaning, good hole quality, deep hole drilling capacity, excellent hole straightness and efficient energy transmission.
There are different drilling accessories that help to create a deeper hole. Usually, the percussion mechanism or hammer is situated right behind the drill bit. The drill pipes transfer the requisite feed force as well as rotation to hammer and bit. Often, compressed air is also provided for the hammer and flushing of cuttings by the drill pipes. The hole gets deeper when the drill pipes add to the drill string successively behind the hammer. While the hammer casing provides a very stable guidance of the drill bit, the piston on the other hand strikes the impact surface of the bit. This helps to avoid the impact energy to pass through any of the joints. So, the impact energy stays constant irrespective of the depth of the hole.
Drill pipes are known as the most important drilling accessories which are used in different applications like DTHR/DR/DTH. The main role of the drill pipe is to transfer rotational thrust and torque from the drill rig rotary head to down hole drilling tools. It also facilitates to transfer the drilling fluid to down hole tools. The main features of an effective drill pipe are- durable in terms of its connections, well-designed to support its own weight, sufficiently rigid length, shouldn't break or bent permanently and capable of handling tremendous forces generated while drilling.
Another method used for drilling is Rotary Drilling with Mud. In this method, the action is completed by rotating a drill pipe by using a power driven rotary table or hydraulic powered top head drive. There is always a bit attached to the bottom of the pipe which is utilised to cut and break up the material as it penetrates the formation. Drilling fluid is pumped through the rotary drills as well as the holes in the bit. The fluid has to flow in an appropriate manner as it helps to make the drilling fast. As the operation proceeds, the rotary drills and bit move downward and it deepens the hole. One more method is Rotary Drilling with Air. The method is same as mud drilling but the only difference is that the mud pump is replaced by a compressor assembly.
