The document discusses offshore pipeline operations, highlighting important factors such as route selection, submarine pipeline characteristics, construction methods, and environmental/legal issues. It details consideration of seabed conditions and the design of pipelines for different environmental conditions, including construction techniques like s-lay, j-lay, and reel-lay systems. Additionally, it addresses environmental risks and concerns related to underwater pipelines, reflecting on past incidents and the potential impact on marine areas.

1. Offshore Pipeline
Operations and
Engineering
Mohammed Ibrahim Alobaid
The First GCC
International
Conference on
Industrial
Engineering and
Operations
Management

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Offshore Platforms and Pipelines
Have you seen them in real life?
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Contents
• Route selection
• Submarine pipeline characteristics
• Pipeline construction
• Stabilization
• Environmental and Legal issues
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Route Selection
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Route selection
There are some standard desk studies that includes:
• A survey of geological maps.
• Bathymetry.
• Fishing charts.
• Aerial and satellite photography
• Getting information from related authorities.
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Route selection
Physical factors
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• The primary physical factor to be considered in submarine
pipeline construction is the state of the seabed – whether
it is smooth (i.e., relatively flat) or uneven (corrugated,
with high points and low points).

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Route selection
Physical factors
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• If it is uneven:
the pipeline will include free spans when it connects two high points,
leaving the section in between unsupported.
• If the soil is not strong enough:
the pipeline may sink into it to an extent where inspection, maintenance
procedures and prospective tie-ins become difficult to carry out.
• At the other extreme:
A rocky seabed is expensive to trench and, at high points, corrosion and
damage of the pipeline's external coating may occur.
• Ideally, the soil should be such as to allow the pipe to settle into it to some
extent, thereby providing it with some lateral stability.

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Route selection
Physical factors
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Submarine Pipeline Characteristics
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Submarine pipeline characteristics
Submarine pipelines generally vary in diameter from
3 inches to 72 inches for high capacity lines
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Submarine pipeline characteristics
Wall thicknesses typically range from (0.39 in) to (3.0 in).
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Submarine pipeline characteristics
The pipe can be designed for fluids at high temperature and
pressure.
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Submarine pipeline characteristics
The walls are made from high-yield strength steel, 350-500
MPa, weldability being one of the main selection criteria
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Submarine pipeline characteristics
• The structure is often shielded against external corrosion by coatings
such as epoxy, supplemented by cathodic protection with sacrificial
anodes.
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Submarine pipeline characteristics
Concrete wrapping provides further protection against corrosion
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Submarine pipeline characteristics
The addition of a concrete coating is also useful to compensate for the
pipeline's negative buoyancy when it carries lower density substances
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Pipeline Construction
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Pipeline construction
Pipeline construction involves two procedures:
1- Assembling many pipe segments into a full line.
2- Installing that line along the desired route.
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Pipeline construction
Most common systems can be used for a submarine
pipeline:
1- S-lay
2- J-lay
3- reel-lay
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Pipeline construction
• In the S-lay system and the
J-lay system, the pipeline
assembly is done at the
installation site, on board a
vessel that has all the
equipment required for
joining the pipe segments:
pipe handling conveyors,
welding stations, X-ray
equipment, joint-coating
module, etc.
The S-lay system + The J-lay system
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Pipeline construction
The S-lay system
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Pipeline construction
The J-lay system
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Video
The S-lay system
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Pipeline construction
• In the reel-lay system, the pipeline is assembled onshore
and is spooled onto a large drum.
• The vessel then goes out to location to lay the pipeline.
The Reel-lay system
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Pipeline construction
The Reel-lay system
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Environmental and Legal issues
Concerns about the environmental risks of underwater pipelines
have been raised on numerous occasions:
• There have been at least two serious incidents involving oil pipelines
on the UK's continental shelf.
• There have also been several "minor spills and gas leaks" involving
other North Sea pipelines.
• In 1980 a pipeline was damaged by a ship's anchor and in 1986 a
pipeline valve failed due to pressure changed.
• Both incidents resulted in oil spills.
• Several Baltic countries expressed concerns about the Nord Stream
pipeline.
• The route of the 1,200 km underwater pipeline would travel through
fishing areas of the Baltic Sea, as well as area where chemical
weapons from World War II had been discarded.
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Resources
• Bai Y. & Bai Q. (2010) Subsea Engineering Handbook. Gulf Professional Publishing, New York, 919 p.
• Barrette, P (2011). "Offshore pipeline protection against seabed gouging by ice: An overview". Cold Regions
Science and Technology. 69: 3–20. doi:10.1016/j.coldregions.2011.06.007.
• Brown R.J. (2006) Past, present, and future towing of pipelines and risers. In: Proceedings of the 38th
Offshore Technology Conference (OTC). Houston, U.S.A.
• Croasdale K., Been K., Crocker G., Peek R. & Verlaan P. (2013) Stamukha loading cases for pipelines in the
Caspian Sea. Proceedings of the 22nd International Conference on Port and Ocean Engineering under
Arctic Conditions (POAC), Espoo, Finland.
• Dean E.T.R. (2010) Offshore Geotechnical Engineering - Principles and Practice, Thomas Telford, Reston,
VA, U.S.A., 520 p.
• Gerwick B.C. (2007) Construction of marine and offshore structures. CRC Press, New York, 795 p.
• Palmer A.C. & Been K. (2011) Pipeline geohazards for Arctic conditions. In: W.O. McCarron
(Editor), Deepwater Foundations and Pipeline Geomechanics, J. Ross Publishing, Fort Lauderdale, Florida,
pp. 171–188.
• Palmer A. C. & King R. A. (2008). Subsea Pipeline Engineering (2nd ed.). Tulsa, USA: Pennwell, 624 p.
• Ramakrishnan T.V. (2008) Offshore engineering. Gene-Tech Books, New Delhi, 347 p.
• Wilson J.F. (2003) Structures in the offshore environment. In: J.F. Wilson (Editor), Dynamics of Offshore
Structures. John Wiley & Sons, Hoboken, New Jersey, U.S.A., pp. 1–16.
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Thank You!