SPAR
Drilling Rig
Group 8
GROUP 8 MEMBERS
NAME
MATRIC NO
AKUJUOBI DAVID EBUKA
160409028
ALADESUYI MOFIYINFOLUWA ISRAEL
160409019
OLOGUNRO WURAOLA HANNAH
160409015
MICHELLE YAKUBU PELUMI
160409042
ADEYOJU CHARLES ADEDAYO
160409006
NWA MFON STEPHEN
160409051
OLADIPO ABDULMALEEK OLAITAN
160401054
AKINSANYA KOFOWOROLA THAMRAT
160401036
SUBAIR HUSSEIN KEHINDE
160401065
ABDULFATTAH OLANIYI AAMIR
160401018
OMO-OJO EKAN
170401522
TANKO UMAR FAROUK
160401026
UMUHUSO CHURCHILL
Some did not contribute o, but lets sha leave them…
SPAR
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A spar is a type of floating oil platform typically used in very deep waters, and is
named for logs used as buoys in shipping that are moored in place vertically.
Spar production platforms have been developed as an alternative to conventional
platforms.
.Similar to an iceberg, the majority of a spar facility is located beneath the water's
surface, providing the facility increased stability. Originally designed as a floating
buoy to acquire oceanographic information, the main component of a spar facility
is the deep-draft floating chamber, or hollow cylindrical hull.
Spars are most prevalent in the US Gulf of Mexico; however, there are also spars
located offshore Malaysia and Norway.
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HOW DID THEY EVOLVE?
• Today, the track record of spar
installations spans three generations of
spar technology and includes both dryand wet-tree applications, with and
without platform rigs..
 The classic spar consists of the
cylindrical hull noted above, with heavy
ballast tanks located at the bottom of
the cylinder.
 The original design for spars was
created in the mid '90s with the first
developed for the Neptune field in the
Gulf of Mexico.
GENERATION 1-CLASSIC SPARS
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EVOLUTION OF SPAR RIGS
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A truss spar has a shorter cylindrical "hard
tank" than a classic spar and has a truss
structure connected to the bottom of the hard
tank.
This truss structure consists of four large
orthogonal "leg" members with X-braces
between each of the legs and heave plates at
intermediate depths to provide damping.
The truss spar is advantageous because it
weighs less than the original design, and
because it requires less steel, which costs
less.
The majority of spars are of this type.
GENERATION 2- TRUSS SPAR RIGS
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EVOLUTION OF SPAR RIGS
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The most recent variation of the spar is the cell
spar, which is a scaled-down version of the original
design.
The cell spar includes six pressure vessels
gathered around a seventh vessel. Resembling
massive hot dogs, these pressure vessels are more
easily and cost-effectively generated through mass
production.
Providing the buoyancy for the facility, the vessels
are held in place by structural steel, which extends
below the vessels and keeps with the deep-draft
design by providing stability.
The cell spar design was only ever used for one
platform, the Red Hawk Spar.
GENERATION 3 - CELL SPAR
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RIG HISTORY
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The first spar was the Brent Spar, a platform
designed for storage and offloading of crude
oil products ( that is were used as FSOs). It
was installed in the Brent Field in June 1976.
The first spar designed for production was
the Neptune spar, located in the Gulf of
Mexico, and was installed in September 1996
by Kerr McGee.
The world's deepest production platform is
Perdido, a truss spar in the Gulf of Mexico,
with a mean water depth of 2,438 meters.
NEPTUNE SPAR
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SCRAP VALUE OF A SPAR
PLATFORM
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This indicates the economical , environmental and resource value
of the components of a decommissioned oil rig.
According to BSEE (Bureau of Safety and Environment
Enforcement),Spars are decommissioned by removing the deck
and releasing the mooring system at the sea bed from the hull
similar to Semi-submersibles.
The Hull of a Spar Platform can be used as artificial reefs. The hull
is towed to a reef site, ballasted and place on the seabed.
RIGS-TO-REEFS:The Red Hawk spar which was decommissioned
in 2014 under the Bureau of Safety and Environmental
Enforcement's "Rigs-to-Reefs" program.
These artificial reefs create underwater habitat for fish to increase
fish populations for sport and commercial fishing and for
numerous recreational diving ventures
A PICTURE OF A HULL OF A SPAR
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TECHNICAL
SPECIFICATIONS OF A
SPAR PLATFORM
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DEPTH HISTORY
• Spars are available in water depths up to 3,000 ft, although existing technology can extend refers to the analogy
of a spar on a ship.
• In September 1996, Oryx Energy installed the first Spar production platform in the Gulf in 1,930 ft of water in
Viosca knoll Block 826. This is a 770-ft long, 70-foot broad diameter cylindrical structure anchored vertically to
the sea floor.
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DEPTH RECORDS OF SPAR PLATFORM
OPERATOR
AREA
BLOCK
STRUCTURE NAME
WATER DEPTH
DATE INSTALLED
Shell Offshore Inc
AC
857
A-Perdido
7835
11/12/2009
Eni US Operating Co.Inc
MC
773
A-Devil’s Tower
5610
2/19/2004
BP E& P Inc
MC
127
A-Horn Mountain
5400
6/29/2002
Anardarko Petrol.. Corp
GC
680
A-Constitution
4970
12/27/2005
Exxon Mobil Corporation
AC
25
A-Hoover
4825
4/25/2000
BP E& P Inc.
GC
782
A-Mad Dog
4420
7/30/2004
Freeport-McMoRan Oil
&Gas LLC
GC
645
A-Hoistein
4340
7/30/2004
Chevron USA Inc
GC
641
A-Tahiti
4000
8/8/2008
Anadarko Petroleum
Corporation
EB
602
A-Nansen
3675
11/10/2001
Noble Energy Inc
VK
826
A-Neptune
1930
11/19/1996
11
RIG
DESIGN
• Support
• Mooring System
• Stability
• Unique Equipment
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HOW IS THE PLATFORM DESIGNED
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The Spar Platform consists of a large-diameter single vertical cylinder supporting a
deck. It has a typical FP topside (surface deck with drilling and production
equipment), three types of risers (production, drilling, and export), and a hull moored
using a taut catenary system of 6–20 lines anchored into the sea floor.
Originally designed as a floating buoy to acquire oceanographic information, the main
component of a spar facility is the deep-draft floating chamber, or hollow cylindrical
hull. The cylinder does not extend all the way to the sea-floor, but instead is tethered
to the bottom by a series of cables and lines.
The deep-draft design makes the spar less affected by wind, wave and currents,
enabling the facility to support both subsea and dry tree developments.
Neutrally buoyant structures such as Spar are dynamically unrestrained and are
allowed to have six degrees of freedom (heave, surge, sway, pitch, roll and yaw)..
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HOW IS THE RIG
SUPPORTED?
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The Spar Platform deck loads are supported by
the buoyancy forces of the hull supporting the
deck.
The Spar platform is designed so that its centre
of gravity is lower than its centre of buoyancy,
hence it is intrinsically stable.
These Buoyancy Forces help to support
equipment and variable weights used to support
drilling and production operations.
Weight control is very important to the design of
Spar platform
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THE EFFECT OF ENVIRONMENTAL LOADS ON THE STABILITY
OF A SPAR PLATFORM
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The cylinder provides stability as it is weighted at the bottom by a chamber filled with a material that
is denser than water (to lower the center of gravity of the platform ).
Environmental loads are loads which are due directly or indirectly to environmental actions. All
external forces which are responses to environmental loads are to be regarded as environmental loads
eg mooring forces and inertia forces.
Environmental Loads in floating platforms such as Spar , are resisted by vessel inertia and stability,
mooring systems it is necessary to determine the inertial loads due to acceleration of the body in
motion.
Mooring and station-keeping are unique requirements for stability in a Spar platform. Station-keeping
is a term used to define a system for keeping the facility within a specified distance from a desired
location. This is typically a requirement of drilling or riser connections to the sea floor, or for running
equipment to the sea floor.
Although The Truss Spar derives no stability from its mooring system, so it does not list or capsize
even when completely disconnected from its mooring
15
MOORING SYSTEM
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Mooring refers to the means for providing a
connection between the structure and the seafloor
for the purposes of securing the structure against
environmental loads
Spars are permanently anchored to the seabed by
way of a spread mooring system composed of
either a chain-wire-chain or chain-polyesterchain configuration
Spread moorings consist of multiple legs that are
connected to the platform by fair-leaders and
tensioners and to the seabed by anchors. In
deepwater, each leg is typically made up of either
steel wire or synthetic rope over most of its
length, with a small segment of chain at the top
and bottom
The mooring legs must resist forces and motions
induced by the platform in response to extreme
100-year return period metocean conditions..
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SOME UNIQUE EQUIPMENTS USED ON
A SPAR PLATFORM
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A MARINE RISER SYSTEM: A marine riser provides
communication and circulation capability between
the surface and the sea floor, and is used at some
point during all offshore drilling. The bottom of the
riser is connected to the BOP stack, which is
connected to the wellhead located at the sea-floor.
SUBSEA BOP STACK :During floating drilling
operations, the potential exists for the drilling rig to
lose station keeping capability and drift off from
over the subsea wellhead. Because of this, the
blowout preventers are located on top of the
wellhead on the sea floor, allowing the well to be
shut in and controlled at the sea floor, independent
of drilling rig location.
A subsea tree is an arrangement of fittings, piping
and valves that is located on top of a wellhead. The
valves can be operated by a diver, ROV or remote
control
It should be noted that SPAR platform can be
operated using both surface and sub-sea BOP
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Operational
Challenges
• SAFETY
• LOGISTICS
• WELL CONTROL
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SAFETY
Some real life cases…
THE BRENT SPAR
The disposal plans of the Brent Spar had safety concerns
because seawater that had been sealed in the Spar's tanks
were hazardous.
Gordon Stirling, the Wood Group's managing director for
engineering projects explained:
"When seawater is kept in anaerobic conditions, organisms
called sulphur-reducing bacteria (SRB) can flourish. They
produce hydrogen sulphide, an extremely poisonous gas, by
reacting with sulphur compounds present in organic
materials such as oil. We believe that it may be present in
significant quantities.
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ACCIDENTS - The Perdido Spar
As at 2012,About 25 incidents throughout the Gulf
have been reported to the Occupational Safety and
Health Administration (OSHA) so far that year, all
relatively minor scrapes like a broken wrist, cuts that
require a few stitches or fingers pinched in doorjambs
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LOGISTICS
Mooring an offshore platform in deep waters requires
long mooring lines.
Therefore, the weight of the mooring hardware is
substantially increased. The additional weight
decreases the platform payload capacity, hence
reducing drilling or production capacity.
SO WHAT WAS THE SOLUTION?
The use of synthetic ropes on mooring systems in lieu of
the traditional wire rope.
The main advantage of this solution is the weight savings
due to the neutrally buoyant characteristics of the synthetic
ropes.
21
LOGISTICS
 In line with the need to reduce weight dictated by the need to explore
deeper waters, another technology has emerged in the last decade:
the use of non-metallic materials.
 These lighter, corrosion resistant materials are employed on gratings
for decks, platforms and walkways, cable trays, and piping. The
industry developed an array of materials to suit the offshore
applications, which brings an inherited safety challenge related to the
fire endurance characteristics.
WHAT DID THEY DO?
 Regulatory bodies and classification societies analyzed and studied
the risks associated with the application of non-metallic materials and
the result was the publication of the ABS Guide for Certification of
FRP Hydrocarbon Production Piping Systems in 2005.
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LOGISTICS - The PERDIDO Spar
• The rotating crews and contractors who work on Perdido must contend with
a 24-hour boat ride or 90-minute helicopter flight.
• Sometimes a new equipment is needed and because these platforms are
remote and in deep waters helicopters are needed, and that increases day
rate.
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CASE STUDY: BRENT SPAR/SHELL CRISIS
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BRENT SPAR was an FSO Platform (Floating Storage Off-loading ) operated by Shell UK. It was installed in June
1976 .
In Early 1995, UK Government announced the approval for deep sea disposal after the submission of Shell’s Final
Abandonment plan to the Department of Trade and industry. And In May 1995 , The UK government granted
disposal license to Shell UK
This decision by Shell to dispose the Spar platform by sinking it in the Atlantic Ocean led to public outrage in
Europe in 1995. Reversing the decision and disassembling the platform for use as a quay in Norway, resolved the
resulting public relations problem, but the damage had been done.
The failure to anticipate the public's reaction reinforced a lack of public confidence in the oil and gas industry, and
it helped motivate government action to regulate the decommissioning of offshore platforms in northwestern
Europe (Wilkinson, 1997; Offshore Staff, 1998)
It becomes a question of business ethics whether a practice that is legal but can lead to an adverse environmental
consequence should nonetheless be pursued because a cost-benefit analysis showed that economic benefits
exceeded economic liabilities. Typically, arguments to pursue an environmentally undesirable practice based on
cost-benefit analyses do not adequately account for intangible costs,
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RECENT DEVELOPMENTS
Developments in deep water spar installation.
• Since the first Spar was installed, significant challenges have been overcome throughout every phase of the Spar
installation. A lot of new things have been incorporated and modifications have been made in the installation of deep
water spar.
• Some of these instances are.
• The inclusion of installation of both driven piles in water depths of up to 4,900 ft, and of suction piles in 8,600 ft of
water for spar anchor pipes.
• The installation of VIV strakes on the belly side of a Spar offshore. This offshore installation eliminates the need to
compromise in the design of these VIV strakes, which will be beneficial for the Spar during the rest of its operational life.
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REFERENCES
Speight, J.G Sub-sea and Deep-water Oil and Gas Science and Technology , 2015
Halkyard, J Handbook of Offshore Engineering ,2005
Fanchi, J.R Integrated Reservoir Asset Management, 2010
Chakrabarti ,S , Capanoglu ,C Handbook of Offshore Engineering
ICF/BSEE, Decommissioning Methodology and Cost Evaluation, Bureau of Safety and Environmental Enforcement
Lyons, W.C ,Plisga, G.J , Standard Handbook of Petroleum and Natural Gas Engineering , Elseiver ,2016
Installation of the World’s deepest spar - https://www.offshore-mag.com/fielddevelopment/article/16763827/installation-of-the-worlds-deepest-spar
Brent Spar Dossier, Shell
Rigzone "How Do Spars Work?“
Shell starts production at Perdido
26
ThankYou
PGG 324
GROUP 8