{{Unreferenced, date=May 2019, bot=noref (GreenC bot) A Normally Unmanned (or Unattended) Installation (NUI) is a type of automated offshore Oil/Gas platform designed to be primarily operated remotely, without the constant presence of personnel. Forties Unity

These generally were characterized by their small size, often consisting of just a

well bay A well bay is an area of an oil platform where the Christmas trees and wellheads are located. It normally consists of two levels, a lower where the wellheads are accessed and an upper where the Xmas Trees are accessed often along with the various ...

with a

helipad A helipad is a landing area or platform for helicopters and powered lift aircraft. While helicopters and powered lift aircraft are able to operate on a variety of relatively flat surfaces, a fabricated helipad provides a clearly marked hard s ...

on top. They are often a compromise of providing the convenience of surface

wellhead A wellhead is the component at the surface of an oil or gas well that provides the structural and pressure-containing interface for the drilling and production equipment. The primary purpose of a wellhead is to provide the suspension point and ...

s, which are easier to build and maintain, while avoiding the high operating costs of a full

production platform An oil platform (or oil rig, offshore platform, oil production platform, and similar terms) is a large structure with facilities to extract and process petroleum and natural gas that lie in rock formations beneath the seabed. Many oil platfor ...

. They are generally only used in shallower water, where constructing many small NUIs is a relatively easy and cheap option as compared to the cost of using subsea wells. Polar Queen and Forties Unity

This can be seen in the Southern

North Sea The North Sea lies between Great Britain, Norway, Denmark, Germany, the Netherlands and Belgium. An epeiric sea on the European continental shelf, it connects to the Atlantic Ocean through the English Channel in the south and the Norwegian S ...

where large numbers of wells are on smaller NUIs, compared with the more northern areas of the continental shelf where fewer larger platforms and subsea sites are the norm. NUIs are also common offshore Western Australia where distances to populated areas are huge. NUIs are commonly serviced from a nearby larger platform, e.g., Mungo serviced from

Marnock Marnock or Marnock of Kilmarnock (died AD 625), also known as Marnan of Narnach, Marnanus, Marnocalso or originally Ernin () was a Scottish monk, bishop and saint. Biography Details on the life of Marnock that have survived to the present da ...

. These installations will include an emergency shelter with essential food and water in order to provide a safe refuge in the event that weather or other considerations prevent a visiting crew from returning to base. Regular visits may be made for routine maintenance and for smaller

well work A well intervention, or well work, is any operation carried out on an oil or gas well during, or at the end of, its productive life that alters the state of the well or well geometry, provides well diagnostics, or manages the production of the wel ...

such as wireline operations. Anything larger requires a

drilling rig A drilling rig is an integrated system that drills wells, such as oil or water wells, or holes for piling and other construction purposes, into the earth's subsurface. Drilling rigs can be massive structures housing equipment used to drill wat ...

to be brought in, but this is still an advantage over subsea wells, which require a

or light intervention vessel for any

well intervention A well intervention, or well work, is any operation carried out on an oil or gas well during, or at the end of, its productive life that alters the state of the well or well geometry, provides well diagnostics, or manages the production of the wel ...

. In recent times NUI has become a phase within the decommissioning of previously manned offshore installations. Platforms would generally be positively isolated from

hydrocarbons In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons are examples of group 14 hydrides. Hydrocarbons are generally colourless and hydrophobic, and their odors are usually weak or ex ...

and flushed clean to suit environmental issues. Platforms would then only be visited infrequently for integrity checks and maintenance of temporary equipment left for power requirements and safety functionality. The platform would then remain in this phase until further decommissioning activities are carried out to remove the topsides in modules or piece small, then remove the

jacket A jacket is a garment for the upper body, usually extending below the hips. A jacket typically has sleeves, and fastens in the front or slightly on the side. A jacket is generally lighter, tighter-fitting, and less insulating than a coat, which ...

See also