This method involves repeatedly lifting and dropping a heavy tool, known as a drilling hammer, onto the ground to create a hole. The drilling hammer may weigh several hundred pounds, and it is attached to the top of the drill stem, which is a long steel pipe.
As the drilling hammer is raised and then allowed to fall onto the ground, it fractures the soil and rock below, creating a hole. The cuttings are then removed using a bailer or other tool, and the process is repeated until the desired depth is reached.
Percussion drilling is often used in areas where the soil is hard and difficult to penetrate, such as in areas with a lot of bedrock or boulders. However, this method can be slow and labor-intensive, and it may not be suitable for drilling deep wells or in areas with loose or sandy soil.
Second method is rotary drilling, which is a water well drilling method that involves using a rotary bit attached to a rotating drill stem to bore through the ground. The drill stem is a long steel pipe that is connected to the bit and is rotated by a rotary table or top drive.
As the bit rotates, it cuts through the soil and rock, and the cuttings are removed from the hole by circulating drilling mud or water. The drilling mud is a mixture of water, clay, and other additives that help to lubricate the bit and stabilize the hole.
Rotary drilling, it can be used in a variety of soil and rock types and is generally faster and more efficient than percussion drilling. It can also drill deeper wells and can be used to install larger diameter casings and screens.
There are several types of rotary drilling, including:
Air Rotary Drilling: This method involves using compressed air to rotate the drill bit and to remove cuttings from the hole.
Mud Rotary Drilling: This is the most common type of rotary drilling, which uses a circulating drilling mud to remove cuttings from the hole.
Dual Rotary Drilling: This method uses two rotating drill stems, one inside the other, to simultaneously drill and case the hole.
Reverse Circulation Drilling: In this method, drilling mud is circulated down the drill stem and up through the annulus between the drill stem and the casing, carrying cuttings to the surface.
The choice of rotary drilling method depends on several factors, including the type of soil or rock being drilled, the depth of the well, and the availability of equipment and resources.