Normally unmanned installation
Encyclopedia
A Normally Unmanned Installation (NUI) is a type of automated offshore Oil/Gas platform
designed to be primarily operated remotely, without the constant presence of personnel.
These generally were characterized by their small size, often consisting of just a well bay
with a helipad
on top.
They are often a compromise of providing the convenience of surface wellhead
s, which are easier to build and maintain, while avoiding the high operating costs of a full production platform.
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.
This can be seen in the Southern North Sea
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 commonly serviced from a nearby larger platform, e.g., Mungo
serviced from Marnock. 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 such as wireline
operations. Anything larger requires a drilling rig
to be brought in, but this is still an advantage over subsea wells, which require a drilling rig
or light intervention vessel for any well intervention
.
In recent times NUI has become a phase within the decommissioning of previously manned offshore installations. Platforms would generally be positively isolated from hydrocarbons 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
.
Oil platform
An oil platform, also referred to as an offshore platform or, somewhat incorrectly, oil rig, is a lаrge structure with facilities to drill wells, to extract and process oil and natural gas, and to temporarily store product until it can be brought to shore for refining and marketing...
designed to be primarily operated remotely, without the constant presence of personnel.
These generally were characterized by their small size, often consisting of just a well bay
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 well control panels, which will have pressure...
with a helipad
Helipad
Helipad is a common abbreviation for helicopter landing pad, a landing area for helicopters. While helicopters are able to operate on a variety of relatively flat surfaces, a fabricated helipad provides a clearly marked hard surface away from obstacles where a helicopter can safely...
on top.
They are often a compromise of providing the convenience of surface wellhead
Wellhead
A wellhead is a general term used to describe 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....
s, which are easier to build and maintain, while avoiding the high operating costs of a full production platform.
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.
This can be seen in the Southern North Sea
North Sea
In the southwest, beyond the Straits of Dover, the North Sea becomes the English Channel connecting to the Atlantic Ocean. In the east, it connects to the Baltic Sea via the Skagerrak and Kattegat, narrow straits that separate Denmark from Norway and Sweden respectively...
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 commonly serviced from a nearby larger platform, e.g., Mungo
Eastern Trough Area Project
The Eastern Trough Area Project, commonly known as ETAP, is a network of nine smaller oil and gas fields in the Central North Sea covering an area up to 35 km in diameter...
serviced from Marnock. 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 such as wireline
Wireline
In the oil and gas industry, the term wireline usually refers to a cabling technology used by operators of oil and gas wells to lower equipment or measurement devices into the well for the purposes of well intervention and reservoir evaluation....
operations. Anything larger requires a drilling rig
Drilling rig
A drilling rig is a machine which creates holes or shafts in the ground. Drilling rigs can be massive structures housing equipment used to drill water wells, oil wells, or natural gas extraction wells, or they can be small enough to be moved manually by one person...
to be brought in, but this is still an advantage over subsea wells, which require a drilling rig
Drilling rig
A drilling rig is a machine which creates holes or shafts in the ground. Drilling rigs can be massive structures housing equipment used to drill water wells, oil wells, or natural gas extraction wells, or they can be small enough to be moved manually by one person...
or light intervention vessel for any well intervention
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 and or well geometry, provides well diagnostics or manages the production of the well....
.
In recent times NUI has become a phase within the decommissioning of previously manned offshore installations. Platforms would generally be positively isolated from hydrocarbons 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
Jacket (disambiguation)
A jacket is a relatively tight-fitting garment for the upper body.Jacket may also refer to:* Jacket , the GPU engine for MATLAB* Jacket , an online poetry magazine...
.