15 - Are FPSOs Shaping The Future Of DeepWater Oil & Gas Production?
Updated: Aug 22, 2018
As we keep pushing Oil exploration frontier towards more remote offshore locations, the cost associated with bringing any oil discovery to shore will keep increasing, especially when pipeline infrastructure is not present, or when it is difficult to connect a pipeline to shore due to geopolitical risks or harsh weather. This is where FPSOs emerge as an ideal solution for remote offshore Oil & Gas production.
What Is A FPSO?
FPSO stands for Floating Production, Storage and Offloading vessel. It is a subset of a wider group of vessels called Floating Production Systems (FPS), which includes:
Floating Storage, and Offloading vessels (FSO)
Floating Production, Storage, and Offloading vessels (FPSO)
Floating Drilling, Production, Storage, and Offloading vessels (FDPSO)
Floating Storage, and Regasification units (FSRU)
Floating Storage, Regasification, and Power-Generation vessels (FSRP)
Floating Storage Regasification, Water-Desalination, and Power-Generation vessels (FSRWP)
Floating Liquified Natural Gas units vessels (FLNG)
Tension-Leg Platforms (TLP)
While each type of FPS offers a different set of functionality, FPSOs remain by far the most popular type of FPS as they account for 60-80% of deployed FPS worldwide.
The world's first FPS is the Transworld 58. It was a semi-submersible rig that was converted in 1975 to a floating production facility with a production manifold, two-stage gravity separator, and a water treatment system.
The first FPSO was called Shell Castellon. it was converted from an oil tanker in 1977 then deployed in the Mediterranean, offshore Spain.
How Does A FPSO Work?
Oil is received by the FPSO from subsea wells through a single dynamic riser. This oil is:
processed through a set of separators located in the top-side of the vessel,
stored in the double-hull beneath the top-side, then
offloaded periodically into shuttle tankers (usually every 6-7 days)
The separated water is treated, mixed with sea-water, then passed through a sulfate reduction plant, while gas is cleaned and compressed through a gas-processing plant. Both water and gas are reinjected into the reservoir to maintain reservoir pressure.
How Does A FPSO Remain In Place?
The riser is connected to a revolving turret system which is built-in or cantilevered off the FPSO. The turret system is anchored to seabed by mooring lines making it a stationary point, around which the vessel can weathervane without twisting the riser. Also, some turret systems are designed to be disconnected and reconnected when temporary abandoning location.
What Are The Advantages Of A FPSO?
FPSOs demonstrate several advantages when compared to fixed platforms. These advantages have been groups under three main categories:
Harsh Weather Evasion - although FPSOs are designed to operate for 20 years at the same location and to sustain harsh weather, their mobility allows them to evade any force majeure such as hurricanes or gigantic icebergs.
Asset Integrity - unlike fixed platforms where their integrity is questioned every time they endure adverse weather conditions, FPSO mobility allows it to escape such events thus eliminating integrity inspection cost. Furthermore; FPSOs can sail to a dry dock facility for reparation or maintenance if necessary.
Redeployment - FPSO can be relocated to other fields, which eliminates decommissioning cost associated with fixed platforms.
Minimal Infrastructure - FPSOs doesn't require an extensive pipeline network.
Marginal Field Development - FPSOs prove to be economically attractive as they allow production from deep-water and ultra-deep-water Oil & Gas field, where fixed platforms and pipeline are not feasible.
Small field development - FPSO is occasionally a feasible solution when deployed in small field with high depletion rate.
Cash-Flow - FPSO usually show earlier cash flow as it takes less time to develop a FPSO than a Fixed Platform
Depreciation - FPSO cost can be depreciated over several fields if it served different locations.
As we are seeing less land discoveries year after year, we are pushing the limit towards remote offshore locations, where installing a fixed platform and stretching a pipeline to shore might prove to be challenging, both economically and technically. This is where FPSOs provide a viable solution which allows to economically produce from such marginal fields.
As FPSOs number is on the rise, they will definitely play a crucial role in the future of the Oil & Gas industry, specially in ultra-deep-water.
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