OFFSHORE DRILLING PБ Maxammadjonov S Rixsilaev D

HISTORY OF OFFSHORE DRILLING 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.Grand Lake St. MarysOhio 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.Summerland fieldSanta Barbara ChannelCalifornia One of the oldest subsea wells is the Bibi Eibat well, which came on stream in 1923 in Azerbaijan.Bibi EibatAzerbaijan In 1946, Magnolia Petroleum (now ExxonMobil) drilled at a site 18 miles (29 km) off the coast, erecting a platform in 18 feet (5.5 m) of water off St. Mary Parish, Louisiana.ExxonMobilSt. Mary Parish, Louisiana

By pumping wells offshore drilling technology are distinguished from surface or underwater wellhead location.

OFFSHORE STRUCTURES Stationary (associated with the seabed) large-block foundation: - Pile - at sea depths of up to 40 m. - Supporting-pile - up to 150 m, - Support m; 2. Mobile support: -Submersible hull - used in shallow waters up to 15 meters -- Jackup rig (jack-up) - to the depths of the sea from 15 to m

Gravity-based structure They are more stable drilling platform gravity. They are equipped with powerful concrete base, rests on the seabed. A GBS can either be steel or concrete and is usually anchored directly onto the seabed.. Steel GBS are predominantly used when there is no or limited availability of crane barges to install a conventional fixed offshore platform, for example in the Caspian Sea

Jack-up drilling rigs A jackup rig or a self-elevating unit is a type of mobile platform that consists of a buoyant hull fitted with a number of movable legs, capable of raising its hull over the surface of the sea.hull

1 -pontoon; 2 - supporting column; 3 - The device supports lifting; 4 - valve; 5 - rig; 6 -Consoles derrick portal; 7 - Storage racks for pipes; 8 - a residential unit; 9 - helipad

Semi-submersible semi- submersible ( semisubmer ged ship ) is a specialised marine vessel used in a number of specific offshore roles such as offshore drilling rigs, safety vessels, oil production platforms, and heavy lift cranes. They are designed with good stability and seakeeping charact eristics.marine vesseloffshore drilling rigsseakeeping

. Stationary platform

Spar platforms A spar is a type of floating oil platform typically used in very deep waters, and is named for logs used as buoys in shipping that are moored in place vertically. Spar production platforms have been developed as an alternative to conventional platformsoil platformlogs used as buoys

Drilling offshore wells with subsea mouth arrangement made with the drilling vessels, semi- submersible and jack-up drilling rigs, as well as the artificial floating islands of ice.

Underwater drilling complex

Seabed installations

Cluster drilling at sea Scrub offshore wells may contain from 12 to 96 wells on a fixed platform.

Transportation of the drilling platform

The cost of drilling wells on the sea The cost of offshore drilling is higher than on land: - The cost of exploration wells (depth of around 500 m) is 3-6 million dollars for the conditions of the Gulf of Mexico million dollars for the conditions of the North Sea. - Up to $ 50 million on the shelf of the Arctic seas..