Petroleum from the sea is extracted via offshore drilling, providing roughly 30% of global oil production. It is formed over millions of years from organic matter (phytoplankton, algae) on the seafloor, which is covered by sediment and subjected to intense pressure. Specialized rigs (jackup, semi-submersible, drill ships) drill into the seabed to extract it. Petroleum is extracted from beneath the seabed through offshore drilling, where massive rigs and drill ships bore through rock layers to access, pump, and transport crude oil found in, for example, the Gulf of Mexico, North Sea, and Brazilian coast. It is a fossil fuel created over millions of years from marine algae, plants, and sediment buried under high pressure.