Which type of percussion drilling method is commonly used?

Cable tool drilling is a percussion drilling method that has been used for many years, particularly for drilling water wells. This technique involves using a heavy bit that is repeatedly lifted and dropped onto the rock or soil, allowing it to break apart through the impact. The cable tool rig consists of a drilling bit attached to a series of cables, which are operated by a hoisting mechanism. This method is effective in penetrating hard formations and is particularly beneficial in areas where water is scarce, as it can reach significant depths and produce high-quality water.

The percussion action of cable tool drilling helps remove the cuttings from the hole by using the action of the bit as it strikes. It is a straightforward technique that does not require the same level of fluid circulation as other methods, which can be advantageous in specific geological conditions.

Other methods like sonic drilling, rotary drilling, and reverse circulation drilling serve different purposes or utilize different mechanisms that might not be classified purely as percussion drills. Sonic drilling, for example, uses high-frequency vibrations to penetrate the ground, while rotary drilling involves a rotating bit to cut through materials, and reverse circulation drilling uses air or fluid to transport cuttings to the surface. Each method has specific applications depending on the geological environment and the purpose of the drilling,