There is another name that is related to the natural gas and it is often referred to as the "casinghead gas". Another name that it is attributed to the natural gas is "associated gas". In the case of the drilling of oil wells the former methods that were used for digging the oil wells centuries before, was to hand dig the well which ultimately was stopped when the oil makes its appearance. This system of hand digging was actually being practiced in the oil fields of Azerbaijan, where it is claimed that the oil wells were dug for nearly hundreds of meters down the earth's crust to finally reveal the crude oil. But with the passage of time this practice has given way to the modern technological methods where drilling machines are being used, which dig wells that are several meters deep. Hence to drill out the oil and natural gas more successfully from the surface of the earth, new techniques like the horizontal drilling and a still newer method like Nitrogen drilling methods are being put to use by the oil drilling companies worldwide.