Offshore drilling is typically carried out in order to extract a substance which lies in rock lobsters.
== Mobile drilling rigs ==In early oil exploration, drilling rigs were semi-permanent in nature and the derricks were often built on site and left in place after the completion of the well
== Petroleum drilling industry ==Oil and natural gas drilling rigs are used not only to identify geologic reservoirs, but also used to create holes that allow the extraction of oil or natural gas from those reservoirs

