Tunnel boring machines are popular for creating tunnels through mountains or underneath the earth’s surface. When comparing hydraulic drills with tunnel boring machines, tunnel boring machines are used for drilling earth surfaces that containing hard rocks and other substances to ease the mining and tunnel construction process. While hydraulic drilling machines are mostly used for construction works like piling and drilling rigs. Also, some other hydraulic drills are used for creating holes on various workpieces. Key differences among these machines lie in their design and construction. The design and construction of the hydraulic drilling machine are mentioned in this article.
Also Read:Hydraulics in Tunnel Boring
When considering the structure of hydraulic drilling rigs, they can be either mounted on mobile machinery(trucks, tracks or trailers) or permanent land or marine-based structures. The rig in the drilling machine is the device used for penetrating the earth to a certain depth underground to exploit minerals. The drilling operation requires a drilling fluid which can be air, water-based mud, air/water, oil-based mud, and synthetic-based fluids. Basic details of all these drilling methods are listed below.
The most popularly used drilling methods include percussion or cable drilling, rotary drilling, dual-wall reverse-circulation drilling, electro-drilling, and directional drilling. The percussion/cable drilling approach was used previously and this has a hammering bit attached to a long cable, that is lowered into a wide-open hole. For percussion/cable drilling, the vertical hole is created using various types of power units like manual lift and drop, compressed air, and electrically driven winches. The rotary drilling method uses hydraulics for operating the drill. The reverse circulation drilling technique uses an outer drill rod with an inner tube. The hollow inner tube will remove the drill cuttings to be transported back to the surface. Electro-drilling is an alternative for rotary, turbo, and positive-displacement motor systems, and is preferred for drilling deep, directional, horizontal, and multilateral wells. Directional drilling is the practice of drilling non-vertical bores.
Read More: Horizontal Directional Drilling
Rotary drilling is preferred for drilling big holes in large quarries, open-pit mines, petroleum extraction, and more(either in the land or sea). Most common applications include petroleum production and geothermal development. These are fully self-propelled hydraulic drilling rigs that are equipped with computer operating systems. Increased flexibility, higher automation, faster drilling, high operational efficiency, and eco-friendliness are the key features of the rotary drill rigs. In this type of drill rig, hydraulic oil pressure is applied for rotating the drilling head for an accurate drilling process.
How do rotary drilling works? The design of the rotary drilling machine contains a rotary table connected to square kelly, which then is connected to the drilling pipe. The mud swivel on the pipe is connected to blowout preventers. The drill with drag bits, sharp cutting edges, or rolling cutters is attached to the pipe that rotates at a velocity of 40-250rpm. The fluid supplied through the pipe will remove the cuttings.