Suction caisson

Oil and gas recovery at great depth could have been a very difficult task without the suction anchor technology, which was developed and used for the first time in the North Sea 30 years ago.

[3] The concept of suction technology was developed for projects where gravity loading is not sufficient for pressing foundation skirts into the ground.

[6] An important development step for the suction caisson technology emerged from cooperation between the former operator in the North Sea, Saga Petroleum AS, and Norwegian Geotechnical Institute (NGI).

Unfortunately on the Snorre oil field, it was difficult to use long piles due to the presence of huge pebbles at 60 m depth under the seabed.

As the installation of oil platforms continued in the North Sea, in areas with poor ground conditions such as soft clays, they were designed to survive even higher storm waves.

The Norwegian Geotechnical Institute (NGI) has been heavily involved with the concept development, design and installation of suction anchors from the start.

The project "Application of offshore bucket foundations and anchors in lieu of conventional designs" (1994-1998) was sponsored by 15 international petroleum and industry companies and was one of the most important studies.

An industry sponsored study on the design and analysis of deepwater anchors in soft clay was completed in 2003, where NGI participated together with OTRC and Centre for Offshore Foundation Systems (COFS) in Australia.

The overall objective was to provide the API Geotechnical Workgroup (RG7) and the Deepstar Joint Industry Project VI with background, data and other information needed to develop a widely applicable recommended practice for the design and installation of deepwater anchors.

The Norwegian classification society DNV (Det Norske Veritas), active worldwide in risk analysis and safety evaluation of special constructions, has produced a recommended practice report on the design procedures for suction anchors which is based on close cooperation with NGI.