This most common type of offshore job exists due to the worldwide demand for oil and petroleum. As demand increases and supply falls, oil companies are constantly in search of new sources of oil and many times they find this deep in the ocean bed of a remote corner of the world. Drilling for oil is a massive effort and requires the constant support and supervision of a highly specialized and trained staff.
There are also less specialized roles like that of cooks, housekeeping staff, painters, welders, roughnecks and floor hands. All the roles involved in drilling for oil comprise of global energy offshore jobs and are by far the most in demand.