What is the most common drilling machine

The most common drilling machine used across various industries and applications is the rotary drilling rig. Rotary Drilling Rigs are versatile and widely employed for drilling boreholes in different geological formations and for various purposes, including water wells, oil and gas exploration, geotechnical investigations, and mineral exploration.

Rotary drilling rigs utilize a rotating drill bit to penetrate the ground. The drill bit is connected to the rig through a drill pipe, which provides the necessary torque and axial force to drive the bit and break through the subsurface formations. As the drill bit rotates, it cuts or crushes the rock or soil, and a drilling fluid (such as water, mud, or air) is circulated through the drill pipe to cool the bit, remove the cuttings, and maintain stability within the borehole.

There are different types of rotary drilling rigs, each designed for specific drilling conditions and depths. Some common types include:

1. Direct Mud Rotary Rigs: These are the most commonly used rotary drilling rigs. They employ a drilling fluid (mud) for both cooling the bit and creating a hydrostatic pressure to prevent formation fluids from entering the borehole. Direct mud rotary rigs are versatile and suitable for a wide range of formations, from soft soils to hard rocks.

2. Reverse Circulation Rigs: Reverse circulation (RC) rigs are primarily used in mineral exploration and water well drilling. They employ a dual-wall drill pipe system, where the drilling fluid is pumped down the outer annular space and the cuttings are brought up through the inner tube. This method allows for efficient sampling of rock chips and improves drilling speed.

3. Air Rotary Rigs: Air rotary rigs use compressed air as the drilling fluid instead of mud or water. The high-velocity air jets at the drill bit break up the rock or soil, and the cuttings are blown out of the borehole. Air rotary drilling is typically used in hard rock formations where water-based drilling fluids may not be effective.

4. Combination Rigs: Combination rigs are versatile drilling systems that combine different drilling methods. They can be equipped with both rotary and percussion drilling systems, allowing for efficient drilling in various formations. Combination rigs are commonly used in geotechnical investigations and environmental drilling.

The choice of the most suitable rotary drilling rig depends on several factors, including the intended purpose of the borehole, the geological conditions, the required depth, and the available resources. Factors such as the size and power of the rig, drilling capabilities, mobility, and the availability of support equipment and personnel also play a role in the selection process.

It's worth noting that while rotary drilling rigs are the most common type of drilling machine, other drilling methods and machines may be utilized depending on specific requirements. For example, for shallow and soft soil drilling, auger drilling rigs may be preferred, while sonic drilling rigs are often used for environmental and geotechnical investigations where sample integrity is of prime importance.