…be accessed through conventional vertical drilling, but the most productive method is usually horizontal drilling. In this technique a well is begun in the traditional way, with the auguring of a pilot hole usually some 6 to 15 metres (20 to 50 feet) deep. This is lined with a steel…

…they are done, these are drilling, blasting, loading and hauling, scaling, and reinforcing. Drilling is done in various ways depending on the size of the opening being driven, the type of rock, and the level of mechanization. Most mines use diesel-powered, rubber-tired carriers on which several drills are mounted; these…

…the first known well was drilled for natural gas, to reported depths of 150 metres (500 feet). The Chinese drilled their wells with bamboo poles and primitive percussion bits for the express purpose of searching for gas in limestones dating to the Late Triassic Epoch (about 237 million to 201.3…

…1920, petroleum engineering focused on drilling problems, such as establishing casing points for water shutoff, designing casing strings, and improving the mechanical operations in drilling and well pumping. In the 1920s, petroleum engineers sought means to improve drilling practices and to improve well design by use of proper tubing sizes,…

Early oil wells were drilled with impact-type tools in a method called cable-tool drilling. A weighted chisel-shaped bit was suspended from a cable to a lever at the surface, where an up-and-down motion of the lever caused the bit

…been sunk through soil by drilling methods. The technique was first used in British practice in 1930 and was subsequently further refined in the Netherlands and Germany. The procedure involves first advancing a pilot hole, then reaming in several stages of enlargement to final diameter, while the walls of the…

…of this technique is ultrasonic drilling, which makes use of pneumatic vibrations at ultrasonic frequencies in place of the standard rotary drill bit. Holes of virtually any shape can be drilled in hard or brittle materials such as glass, germanium, or ceramic.

…part of the Deep Sea Drilling Project conducted from 1968 to 1983 by the U.S. government, the drilling ship Glomar Challenger undertook several cruises of Antarctic and subantarctic waters to gather and study materials on and below the ocean floor. Expeditions included one between Australia and the Ross Sea (1972–73);…