Well drilling is the process of drilling a hole in the ground either for exploration of the nature of the material underground or for the extraction of a natural resource such as water, natural gas, or petroleum.
The earliest water wells were probably shallow pits dug by hand in regions where the water table approached the surface, possibly with masonry walls lining the interior to prevent collapse. Modern drilling techniques utilize long drill shafts, producing holes much narrower and deeper than could be produced by human labor.
See also rock drilling.