Condeep
Condeep (abbreviation for concrete deep water structure - concrete deep sea structure ) is a basic structure for drilling rigs . It consists of a concrete base in the form of a large oil tank from which three or four columns extend above the surface of the water.
Condeep structures are up to 300 meters deep, the columns also extend about 30 meters above the sea surface. The actual platform is not part of the Condeep construction. The manufacturer is Norwegian Contractors based in Stavanger .
Oil and gas companies use Condeep structures in the North Sea . In contrast to older constructions, the basic structure is no longer made of steel, but of reinforced concrete. The concept is specifically geared to the difficult weather conditions and - for the conditions at the time - deep water depths in the North Sea.
After the concrete tank in the Ekofisk field proved to be a success, Norwegian Contractors expanded the concept and introduced Condeep as the standard platform in 1973.
Troll A
Troll A in the Troll oil field is the largest Condeep structure to date and the heaviest structure moved by people. Norwegian Contractors built it with 2,000 workers over a period of four years until it was used for natural gas production in 1995.
The platform is 472 meters high and weighs 1.2 million tons. It is built from 245,000 m³ of concrete and 100,000 tons of steel for reinforcement. It extends 300 meters below the sea surface and lies a further 35 meters in the sea floor for stability.
Condeep platforms in the North Sea
| Oil rig | depth | Operator and year |
|---|---|---|
| Ekofisk | 70 m | Phillips , 1973 |
| Frigg CDP1 | 104 m | Total , 1975 |
| Beryl A Condeep | 120 m | Mobile , 1975 |
| Brent B Condeep | 140 m | Shell , 1975 |
| Brent D Condeep | 140 m | Shell, 1976 |
| Frigg TCP2 Condeep | 104 m | Eleven , 1977 |
| Statfjord A Condeep | 146 m | Mobile , 1977 |
| Statfjord B Condeep | 146 m | Mobil, 1981 |
| Statfjord C Condeep | 146 m | Mobil, 1984 |
| Gullfaks A Condeep | 135 m | Statoil , 1986 |
| Gullfaks B Condeep | 142 m | Statoil, 1987 |
| Oseberg A Condeep | 109 m | Norsk Hydro , 1988 |
| Gullfak's C Condeep | 216 m | Statoil, 1989 |
| Draugen Condeep | 251 m | Shell, 1993 |
| Sleipner A Condeep * | 82 m | Statoil * |
| Troll Condeep | 303 m | Norske Shell, 1995 |
| Heidrun TLP | 350 m | Conoco , 1995 |
- The original Sleipner A platform sank during trials on August 23, 1991 in the Gandsfjord . In 1993 Norwegian Contractors built a new platform.