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 10,000 feet (3,000 m). In shallower waters the mobile units are anchored to the seabed, however in deeper water (>5,000 feet (1,500 m)) the semisubmersibles or drillships are maintained at the required drilling location using dynamic positioning.