The conversion of a transportation vessel into a FPSO is a common practice used in multiple situations such as costs reduction, shorter lead time or asset management.
The total capital expenditure to acquire an old tanker and to convert it into a production unit such as a FPSO may costs some US$ hundreds million while the design, engineering and construction of a new-build FPSO of the same capacity may reach quickly the US$ billion.
In addition many shipyards may be able to perform this conversion while a few will have the capacity to hold the hull of a new-build FPSO in construction.
This availability of the shipyards has an impact on the costs but also on the lead time.
For companies operating tankers and FPSOs, the conversion of tankers into FPSO may also be an easy and efficient way to optimize its assets management, since the value produced by a FPSO may be ten times higher than a simple tanker.
It is also the best way to give to an old transportation vessel and second life instead of decommissioning it.
This conversion process may also apply to other types of applications such as:
– Floating Production and Offloading (FPO) unit
– Floating Storage and Regasification Unit (FSRU)
Each one of these types of vessel must then meet the requirements of the applications regarding the geographical location, storage capacity, space and weight capacities to receive all the necessary equipment.
Therefore the selection of the transportation vessel is critical to allow the conversion.
Then this old vessel must be inspected and assessed to check how much:
– Its life cycle may be extended
– It would costs to revamp it before the conversion itself.
When validated the vessel requires engineering work to define how to make the best used of the available volume and load available on the vessel such as:
– Structural analysis
– Motion Response Analysis
The typical equipment or modifications to be executed for the conversion are about the:
– Upgrade of the naval systems
– Integration of the turret systems
– Topside arrangement
– Living quarter
– Helicopter deck
– Process modules
– Process control system and electrical system
– Power generation and electrical distribution
Then depending on the applications the converted FPSO should also include:
– Oil and gas central processing units
– Gas lift system
– Gas or water injection system.
The accumulation of these equipment and systems to be integrated increases with the size and complexity of the oil and gas field where the converted FPSO should be installed.
Meaning that this accumulation of constraints on a simple shuttle tanker may exceed the capacities of any existing vessel or at a costs and risk that it will require the construction of a new-build FPSO.
Therefore the converted FPSO will be mostly used for small or medium size oil and gas offshore fields where the quality of the crude oil and the raw natural gas is good enough to minimize the processing operations on board.