Oil wells are holes drilled into the rock strata to either find oil or pump out oil trapped in reservoirs below the surface.

Drilling is the process of creating perforations called oil wells. This oil is then is pumped out using advanced machinery and techniques.

Oil rigs are machines used for to drill oil wells. These rigs utilize diesel engines, generators, hoisting systems, a turn table, a drill string, drill bits, drill collars, pumps, hoses and pipes, and more.

A drill bit, a collar and a drill pipe are placed in a starter hole as the first step of drilling. Next, once a pre-set depth is reached, the casing pipe (a large-diameter concrete pipe) is used and lines the drill hole and is cemented into the hole. When the final depth is reached, oil will flow into the casing in a controlled manner. A multi-valved structure called a Christmas tree allows operators to control the amount of oil flowing from the well.

Once oil begins to flow, the rig is replaced with equipment used to extract oil from the well. In some cases, electric motors and pumps are used to pump out the oil. If the oil is very thick, sometimes steam under high pressure is injected through a second hole which thins the oil and allows for smoother pumping.