Offshore drilling is typically carried out in order to explore for petroleum.
== Main offshore fields ==Notable offshore fields include:the North Seathe Gulf of Mexico (offshore Texas, Louisiana, Mississippi, and Alabama)California (in the Los Angeles Basin and Santa Barbara Channel, part of the Ventura Basin)the Caspian Sea (notably some major fields offshore Azerbaijan)the Campos and Santos Basins off the coasts of BrazilNewfoundland and Nova Scotia (Atlantic Canada)several fields off West Africa most notably west of Nigeria and Angolaoffshore fields in South East Asia and Sakhalin, Russiamajor offshore oil fields are located in the Persian Gulf such as Safaniya, Manifa and Marjan which belong to Saudi Arabia and are developed by Saudi Aramco
 Often used while drilling oil and natural gas wells and on exploration drilling rigs, drilling fluids are also used for much simpler boreholes, such as water wells

