VSH Turòa nad Bodvou - Nemetschek Scia

Introduction
This project is included in the development of the second phase
of the offshore field of Rosa, located at 200 km from the Angolan
coast, in the block 17 * operated by Total E&P Angola.
To produce oil and gas, Total had to install a subsea production
system in this depth of water, connect hundreds of pieces of equipment
and set up flow lines and risers to bring effluent up to the
FPSO.
The Girassol FPSO (Floating Production Storage Offloading) is
a production and storage ship that has the advantage of being
fully autonomous. The wellheads are installed on the seabed and
connected to the surface facilities by rigid flow lines on the seabed
and riser systems that bring the effluent up to the surface. These
systems are designed to handle extreme ocean states and weather
conditions. The FPSO comprises a seawater disulphating unit, an
oil treatment and stabilisation plant as well as pumps, generators
and of course oil storage tanks. The combined plant can process up
to 200,000 barrels per day of crude oil, can disulphate and re-inject
400,000 b/d of seawater and store 2 million barrels of processed
crude. The oil is then piped to the offloading buoy moored 2 km
from the FPSO.
Module 5
For the Rosa development, Total ordered to Suez-Ondeo the supply
of a desalinisation skid to produce treated seawater (module 5).
Ondeo takes in charge the general design of this skid with HP
pumps, osmosis tubes, tanks, valves, instrumentation, etc. This skid
had to be ‘key on door’. Also some Belgian companies were active
in this project: CTI (Seilles) for the manufacturing of the steel structure
and piping, Ensival (Verviers) for the pumps, ATI (Thimister) for
electricity and instrumentation and EIV for the design and calculation
of the steel structure.
Data of the equipment:
• Length: 14 m
• Width: 8 m
• Height (with lifting frame): 6 m
• Total weight: 138 To (lifting configuration)
• Weight of steel structure: 64 To
The module is composed of different parts:
• Structure of the main frame;
• Structure to support monorails for maintenance of pumps (3 HP
pumps with weight of 10 To each);
• Structure to support osmosis tubes, with walkways;
• Structure to support biocide tanks (at 4.5 m height) with
walkways;
• Lifting frame for a one hook lifting (this one will be cut off after
installation).
The specificities of this project, like these of all the other modules
on the FPSO, are that they have to be calculated for different
configurations:
• In Place: equipment in place on the FPSO, with operating conditions
and taking into account roll and pitch, wind;
• Transportation: equipment on the barge for the travel to the
FPSO (from Rotterdam to Girassol), taking into account more
severe conditions of roll and pitch, in relation with the size of
the barge;
• Lifting with one crane: equipment to be lifted on the FPSO with
one floating crane, taking into account the centre of gravity, the
calculation and the design of the shackles and the pad eyes;
• Installation: this part includes the calculation of the bumpers
and shocks with the installation guides;
• Lifting with two cranes: equipment to be lifted on the manufacturing
workshop yard;
• Load-out: equipment to be transported with a trailer between
the workshop and the yard.
As these configurations required a lot of information, the calculation
files were very big to work with. For this reason, we used
different files for these different configurations. For this description,
we only join the calculation file for the lifting configuration. For the
other files, the calculation model is quite the same, except lifting
frame and bumpers.
For the calculation, some other difficulties came from the habits
of the petroleum sector: they are working with US standards, as
API-AISC, and they use usually a specific calculation software (they
didn’t know anything about SCIA). For the first problem, although
a specific module of SCIA•ESA PT exists for US-code, we discussed
with the customer to use Euro code with some adaptations. For
the second problem, they mentioned the advantage of SCIA with
its graphic interface, more friendly and easy to use.
The calculation required a long preparation to envisage all the
combinations for the different configurations.
For example, for the in-place configuration, we have to combine:
• Dead weight of the structure;
• Weight of the equipments (pumps, piping, tanks,...);
• Contents of the equipments;
• Overload for the walkways;
• Wind in the different directions;
• Roll and pitch due to the sea.
For the calculation report, due to particular requirements of our
customer, we used the classical word format file, including tables
and graphics from SCIA•ESA PT. This method didn’t cause any
problem.
In conclusion, this type of project was a little bit new for our
company, especially with all the specifications in relation with the
fact that this equipment had to operate on a floating structure, but
we learned many things about the working methods of this sector.
Total Rosa – Girassol – Module 5
SCIA•ESA PT helped us to meet the multiple requirements of our
customer.
* Sociedade Nacional de Combustiveis de Angola (Sonangol) is the
Block 17 Concessionaire. Total E&P Angola is the Operator in the
Block. Total’s coventurers are Esso Exploration Angola (Block 17)
Ltd., BP Exploration (Angola) Ltd., Statoil Angola Block 17 AS and
Norsk Hydro Dezassete AS.
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