Offshore drilling is a mechanical process where a wellbore is drilled below the seabed. It is typically carried out in order to explore for and subsequently extract petroleum which lies in rock formations beneath the seabed. Most commonly, the term is used to describe drilling activities on the continental shelf, though the term can also be applied to drilling in lakes, inshore waters and inland seas.
Offshore drilling presents environmental challenges, both from the produced hydrocarbons and the materials used during the drilling operation. Controversies include the ongoing US offshore drilling debate.
There are many different types of facilities from which offshore drilling operations take place. These include bottom founded drilling rigs (jackup barges and swamp barges), combined drilling and production facilities either bottom founded or floating platforms, and deepwater mobile offshore drilling units (MODU) including semi-submersibles and drillships. These are capable of operating in water depths up to 3,000 metres (9,800ft). In shallower waters the mobile units are anchored to the seabed, however in deeper water (more than 1,500 metres (4,900ft) the semisubmersibles or drillships are maintained at the required drilling location using dynamic positioning.
Offshore oil installations have also been asked to ensure immediate return of all manpower, and two of India's largest ports - Kandla and Mundra - located in Gujarat have been alerted while other ports have been advised for preventive action.
Offshore oil installations have also been asked to ensure the immediate return of all manpower, and two of India’s largest ports — Kandla and Mundra — located in Gujarat have been alerted while other ports have been advised for preventive action ... .