Subsea (technology) - Oil and Gas

Oil and Gas

Oil and gas fields reside beneath many inland waters and offshore areas around the world, and in the oil and gas industry the term subsea relates to the exploration, drilling and development of oil and gas fields in underwater locations.

Under water oil field facilities are generically referred to using a subsea prefix, such as subsea well, subsea field, subsea project, and subsea development.

Subsea oil field developments are usually split into Shallow water and Deepwater categories to distinguish between the different facilities and approaches that are needed.

The term shallow water or shelf is used for shallow water depths where bottom-founded facilities like jackup drilling rigs and fixed offshore structures can be used, and where saturation diving is feasible.

Deepwater is a term often used to refer to offshore projects located in water depths greater than around 600 feet, where floating drilling vessels and floating oil platforms are used, and remotely operated underwater vehicles are required as manned diving is not practical.

Subsea completions can be traced back to 1943 with the Lake Erie completion at a 35-ft water depth. The well had a land-type Christmas tree that required diver intervention for installation, maintenance, and flow line connections.

Shell completed its first subsea well in the Gulf of Mexico in 1961

The first known subsea ultra-high pressure waterjet system capable of operating below 5,000 ft was developed in 2010 by Jet Edge and Chukar Waterjet. It was used to blast away hydrates that were clogging a containment system at the Gulf oil spill site.