The Topsides are the surface installations allowing the drilling and/or production and/or processing of offshore hydrocarbons.
Normally used as a plural the Topsides comes from the ship building industry to designate all the portion of the ship coming on the top of the hull or above the waterline.
It has also been adopted for the offshore platforms even though they do not have any hull, except the submersible or semi-submersible platforms, because of their design in two parts:
– A structure in steel or concrete supporting the platform, the biggest parts of this structure being mostly below the waterline
– A production unit, whatever it is, lying on top of the deck of the supporting structure.
To facilitate the construction of the platforms or FPSO and similar vessels, these Topsides are designed by modules in order to facilitate handling and assembling with heavy duty cranes on the shipyards.
These modules contains all the necessary functions to operate the platform of the vessel,:
– Utilities to generate power and all other needs on board
– Living quarters to host all the people on board
– Water or gas injection
– Helicopter deck and all safety equipment
– Drilling equipment for the drilling ships or rigs
With the evolution of the technology and the reduction of the costs, these Topside modules may be produced in different places of the world, then shipped to the shipyard where the hull or the structure of the platform is assembled.
In some cases it may be the opposite, when the construction of a hull or the structure of a platform is completed in the shipyard, it may be pulled to another shipyard to receive all the Topside modules.
This modular design of the Topsides helps the companies to benefit from the best technologies available around the globe and to compromise with the costs and/or the local content requirements which may also influence the whole construction process.
After some years of operations, this modular design of the Topsides also facilitate revamping and upgrade of the platform or vessel without affecting the structure of the hull.