INGENIEUR
Summary of Comparison Integrated and Modular Concept Method
Aspect
Integrated Concept
Modular Concept
Engineering
analysis
Additional marine and structural analyses
for offshore installation.
Lift, transportation, installation and load
out analysis.
Structure
configuration
Requires extra tonnage for LSF, jacket
design alteration and piles but less steel
material for module interfacing and its
lifting integrity.
Requires extra tonnage for module
interfacing, lifting integrity and for MSF.
Deck
structural
strength
requirements
Deck strength is usually not governed by
the installation loads. The strength during
sea-fastening and transportation need to
be checked. Total deck weight is limited by
barge capacity.
Deck strength may be governed by
installation loads. Strength during seafastening and transportation are not very
crucial as the support of the structure lies
directly on the barge/vessel. Deck weight
is limited by derrick lift barge capacity
(<2000mT).
Ballasting
Transportation vessel own ballasting
system for easier control and flexibility
when transferring load onto vessel.
Transportation barge can use external
ballasting system.
Site
preparation
and yard
capacity
Installation of skid beam is necessary to
transport the structure. A thorough yard
assessment is required; bulk capacity,
wharf depth, cranes, equipment etc.
Limited number of capable yards.
Preparation varies depending on load out
method used. All standard fabrication yards
are capable.
Load out
methodology
Skidding is a necessity and no Heavy-Lift
crane Vessel (HLV) is required. LSF design
required upfront.
Open to options of skidding, rolling or lifting
which may require the use of HLV.
Barge
availability
and selection
Limited vessel availability requiring lock-in
as early as two years prior to installation
and during FEED stage.
Crane barges (<2000MT) are readily
available, flexibility of selecting during
fabrication stage.
Sensitivity to
weather
More sensitive during load-out process but
less exposure to weather downtime due to
shorter offshore duration.
Load-out is less sensitive and can be
executed throughout the year but the
longer offshore work duration is subjected
to substantial exposure to weather
downtime.
Installation
requirements
Cargo barge rigged with installation
equipment. Fendering and mooring
systems required. If DP system available,
significant advantage.
Inter-module fendering and mooring
systems required. Plus, lifting gear and
spreader also required.
Overall cost
Additional fabrication cost if yard
reinforcement and dredging are required.
Cheaper overall cost due to cheaper
installation and HUC costs.
Lower fabrication cost but higher
installation and HUC cost due to higher
barge rental rate and offshore labour rate.
Higher overall cost.
Overall
Schedule
Significant schedule advantage; able to
reach first oil approximately six months
earlier.
Slightly shorter fabrication duration but
longer installation and HUC duration.
Longer overall schedule.
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VOL
- JUNE
2016
VOL66
55APRIL
JUNE
2013