<P> 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 . </P> <P> 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 (9,800 ft). In shallower waters the mobile units are anchored to the seabed, however in deeper water (more than 1,500 metres (4,900 ft) the semisubmersibles or drillships are maintained at the required drilling location using dynamic positioning . </P> <P> Around 1891, the first submerged oil wells were drilled from platforms built on piles in the fresh waters of the Grand Lake St. Marys (a.k.a. Mercer County Reservoir) in Ohio . The wells were developed by small local companies such as Bryson, Riley Oil, German - American and Banker's Oil . </P> <P> Around 1896, the first submerged oil wells in salt water were drilled in the portion of the Summerland field extending under the Santa Barbara Channel in California . The wells were drilled from piers extending from land out into the channel . </P>

Where was the first offshore oil well drilled