Oil drilling is drilling into the bedrock to look for oil or gas. At discovery drill more holes to determine the extent of any oilfield. During Crushing drilling a three-headed diamond -bit- is often used for crushing rock to the cuttings. By pumping, drilling fluid down the drill takes place and the bottom of the hole is pressed and then cuttings are done up the drill rig for analysis. By turbine drilling mud is pumped at high pressure down through the drill string. Pressure causes the bit to rotate and thereby crushing the rock.

This method is widely used because drilling is quick in loose formations and because the drill bit can be attached to a knee joint by directional drilling. By coring the lower part of the drill string is rotated so as to cut out an entire core of the bore hole. Formation is analyzed very thoroughly.