Oil drilling is the process by which tubing is bored through the Earth's surface and a well is established. A pump is connected to the tube and the petroleum under the surface is forcibly removed from underground. Oil drilling is a highly-specialized business that grew into the largest industry on the planet by the early 21st century.
The first oil drilling occurred in China during the 4th century. It expanded throughout Asia and the Middle East by the 8th century. Marco Polo reported to Europe the volume of oil drilling that existed in the East during the 13th century.
Until the late 19th century, oil drilling only occurred where the oil was readily available near the surface. Edwin Drake created a method of drilling using pipes that allowed for deeper exploration and prevented the collapse of the borehole. This method is still used today.
The standard oil drilling process is conducted by boring a hole between 5 and 36 inches into the earth. A drill string is used, which is a series of tubes put together that continue to dig deeper until oil is found.
Cement is generally placed on the outside of the drill string in an effort to prevent the borehole from collapsing. This also helps prevent a loss of pressurization, which can lead to a possible explosion or collapse. This is accompanied by back pressure holes being drilled.
The drill bits vary greatly depending on the type of rock that is being drilled through. To make the work easier, drilling fluid is pumped down into the piping. This complex mixture of chemicals and mud brings rocks to the surface and keeps the drill bit cool.