DECOMMISSIONING INSIGHT REPORT
2016
70
FPSO
Floating, production, storage and offloading vessel – a floating vessel used
by the offshore oil and gas industry for the processing of hydrocarbons,
storage of oil and the offloading of the oil either to a tanker or into a
pipeline.
Hydraulic workover unit
Remedial work carried out in a well using a mast powered by
hydraulic fluid.
Integral rig
Fixed rig installed at the well location, usually self-contained, with steel or
concrete legs anchored to the seafloor.
Intervention
Well servicing operations conducted within a completed wellbore to
restore or improve production or injection.
Jack-up rig
Self-contained combination drilling rig and barge with legs that can be
raised and lowered independently onto the seafloor.
Jumper
A short segment of flexible pipe with a connector half at either end. A
jumper is commonly used to connect flowlines and/or subsea facilities
together.
Lift-installed jackets
These structures weigh less than 10,000 tonnes and are yard fabricated
before being transported horizontally or vertically on a barge to the field.
Once at the field, the jacket is lifted from the barge into position using a
suitable crane vessel.
Making safe
‘Making safe’ of facilities includes cleaning, freeing equipment of
hydrocarbons, disconnection and physical isolation, and waste
management. ‘Making safe’ of pipelines involves depressurising them and
removing any hydrocarbons. Then the pipelines are cleaned and purged,
with the cleaning programme based on the specific needs of the system.
This may involve the use of pigs, which are maintenance tools used to
clean or inspect the insides of pipelines.
Manifold
A manifold in the context of oil and gas production is a pipe to which wells
are connected in order to collect, co-mingle and direct fluid flow from
more than one well. Such an installation can be on a platform or on the
seabed for accumulating several subsea wells. Manifolds can be used for
the distribution of fluids for injection into a series of wells.
Mattresses
Mattresses are often used to provide protection, for stabilisation, and as
crossover support for pipelines. These comprise flexible blocks linked with
rope or wire, or concrete forms or grout bags filled with cement.
MER UK
Maximising Economic Recovery from the UKCS
Milling
A mill or similar downhole tool is used to remove casing in the well where
a barrier needs to be installed in case of pressure or potential movement
of hydrocarbons behind the casing. The objective is to prevent fluids
flowing into another formation or to the surface.
Modular rig
Rig designed in modules that can be lifted onto a platform by crane to be
erected on site.
NNS
Northern North Sea
NUI
Normally Unmanned Installation
OGA
Oil and Gas Authority
Over-trawl surveys
Over-trawl surveys make sure the seabed is safe for normal fishing
activities to resume.
Pig
A device used to clean pipelines.