Subsea
From Wikipedia, the free encyclopedia
Subsea is a general term frequently used to refer to equipment, technology, and methods employed to explore, drill, and develop oil and gas fields that exist below the ocean floors. This may be in "shallow" or "deepwater".
Deepwater is a term often used to refer to subsea projects located in water depths greater than 1,000 feet, and may incude floating drill vessels, semi-sub rigs or Semi-submersible Platforms.
"Shallow" or shelf" is used for shallower depths and can include standing Jackup Rigs or similar.
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[edit] Systems
Subsea production systems can range in complexity from a single satellite well with a flowline linked to a fixed platform, FPSO or an onshore installation, to several wells on a template or clustered around a manifold, and transferring to a fixed or floating facility, or directly to an onshore installation. [1]
Subsea production systems can be used to develop reservoirs, or parts of reservoirs, which require drilling of the wells from more than one location. Deep water conditions, or even ultradeep water conditions, can also inherently dictate development of a field by means of a subsea production system, since traditional surface facilities such as on a steel-piled jacket, might be either technically unfeasible or uneconomical due to the water depth. [2]
Subsea hydrocarbon (oil and gas) extraction has an exceptionally safe record and has been going on for approximately 100 years. The first subsea well was actually in a Lake - one of the Great Lakes in the USA and was in only a few feet of water.
Oil and gas fields reside in deep water and shallow water around the world. When they are under water and tapped into for the hydrocarbon production, these are generically called subsea wells, fields, projects, development, or other similar terms.
Subsea production systems can be used to develop reservoirs, or parts of reservoirs, which require drilling of the wells from more than one location. Deep water conditions, or even ultradeep water conditions, can also inherently dictate development of a field by means of a subsea production system, since traditional surface facilities such as on a steel-piled jacket, might be either technically unfeasible or uneconomical due to the water depth.[3]
The development of subsea oil and gas fields requires specialized equipment. The equipment must be reliable enough to safe guard the environment, and make the exploitation of the subsea hydrocarbons economically feasible. The deployment of such equipment requires specialized and expensive vessels, which need to be equipped with diving equipment for relatively shallow equipment work (i.e. a few hundred feet water depth maximum), and robotic equipment for deeper water depths. Any requirement to repair or intervene with installed subsea equipment is thus normally very expensive. This type of expense can result in economic failure of the subsea development.
[edit] Remotely Operated Vehicles
Remotely Operated Vehicles (ROV's) are robotic pieces of equipment operated from afar to perform tasks on the sea floor. ROV's are available in a wide variety of function capabilities and complexities from simple "eyeball" camera devices, to multi-appendage machines that require multiple operators to operate or "fly" the equipment.
[edit] Organisations
A number of professional societies and organizations are involved with the subsea industry around the world. Such groups include Society of Petroleum Engineers (SPE), American Petroleum Institute (API), American Society of Mechanical Engineers (ASME), National Association of Corrosion Engineers (Nace).
Government agencies administer regulations in their territorial waters around the world. Examples of such government agencies are the Minerals Management Service (MMS, US), Norwegian Petroleum Directorate (NPD, Norway), and Health & Safety Executive (HSE, UK). The MMS administers the mineral resources in the US (using Code of Federal Regulations (CFR)) and provides management of the country's hydrocarbon resources.
