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offshore floating units seem offering a good and
flexible solution to exploit gas reserves.
FLNG offers now an economically feasible solution
for development of gas reserves that were
previously perceived as being either stranded or
uneconomic by means of traditional schemes.
FLNG is designed as a fully stand-alone system
for field development and, as such, has extensive
pre-treatment facilities that can handle untreated
well fluids, liquefy the cleaned gas and then store it field.
in its own tanks. These liquefaction and treatment
systems onboard the floater make independent
this unit of any infrastructure and eliminate the need floating unit ever built in the world. With its 488 m
for new pipelines, platforms or separate by-product
storage.
From small scall to large
scale FLNG
As Shell FLNG Prelude is becoming a reality,
the world is looking forward to see other FLNG
units appearing in the following years. In 2022,
Clarkson Research Services (Jordan D. K., 2014
[3]) estimates that about 22 FLNG units could be
in operation in the world. From small scale FLNG
projects based inshore to huge FLNG projects
located at more than 200 km from coasts, a large
panel of units is appearing as economical viable
solution.
The giants
The family of the mid or large scale FLNG is the
most common solution developed by the oil & gas
companies as it allows the development of large
fields, often far from coastal areas and where
pipelines will be very costly to build. In the case
of large reserves, this solution seems the most
adapted one as a higher production capacity will
allow exploiting resources in an optimum timeframe
Fig. 2 - Offshore LNG
Terminals around the World
90 Impiantistica Italiana - Maggio-Giugno 2015
of 20 or 25 years that correspond basically to
the standard period the unit will be covered by
a classification society. Of course, life extension
and then extension of class certificate is always
possible but main target of these large scale units
remain to empty a field as quick as possible to be
relocated in another field that will maximize again
the production capacity that dropped to only 10%
of the nominal capacity at the end of the life of a
With respect to that, Prelude FLNG appears as
the first installation of its kind but also the biggest
long and 74 m wide, Prelude will be installed in the
Browse Basin in Australia at approximately 250 m
waterdepth. Once operational, the Prelude FLNG
facility will produce at least 5.3 million tonnes per
annum (mtpa) of liquids: 3.6 mtpa of LNG, 1.3
mtpa of condensate (equivalent to 35,000 bbl/d)
and 0.4 mtpa of LPG.
The minis
It is a common to think that the larger the project
is, the cheaper each produced ton of LNG will be.
However, for very small fields, the reserves are not
always sufficient to justify large LNG plants. This
concern is particularly relevant when considering
offshore liquefaction plants which are expensive
projects (Jeanneau, 2013 [4]).
Exmar has been the first one to understand the
limitation of huge FLNG and has decided to develop
its mini-FLNG concept. With 0.5 mtpa and only
16,000 m3 storage tank, Caribbean FLNG appears
as a challenger in the FLNG world. With a barge
shape solution close to the coastal area, protected
of extreme weather and moored with spud piles,
Caribbean FLNG is perfectly adapted to develop
stranded gas reserves that would be inadequate to
support a traditional baseload LNG project.
With the drop of oil & gas prices, Exmar considers