Subsea wells are essentially the same as dry completion wells. However, mechanically they are placed in a Subsea structure (template) that allows the wells to be drilled and serviced remotely from the surface, and protects from damage e.g. from trawlers. The wellhead is placed in a slot in the template where it mates to the outgoing pipeline as well as hydraulic and electric control signals. Ill: Statoil Control is from the surface where a hydraulic power unit (HPU) provides hydraulic power to the subsea installation via an umbilical. The umbilical is a composite cable containing tension wires, hydraulic pipes, electrical power and control and communication signals. A control pod with inert gas and/or oil protection contains control electronics, and operates most equipment Subsea via hydraulic switches. More complex Subsea solutions may contain subsea separation/stabilization and electrical multiphase pumping. This may be necessary if reservoir pressure is low, offset (distance to main facility) is long or there are flow assurance problems so that the gas and liquids will not stably flow to the surface. Product is piped back through pipelines and risers to the surface. The main choke may be located topside.

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