Jan. 2001 Vol. 222 No. 1
Feature Article
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REGIONAL FOCUS: U.S. GULF OF MEXICO
The FPSO market: Available assistance from ABS
Part 1 ABS (the American Bureau of Shipping) has become involved
in design / construction / maintenance of vessels, and offers several important services to guide prospective
entrants to FPSO/FPS markets
Malcolm Sharples, Vice President of Offshore
Project Development, ABS
ithin
the next decade, as many as 50 FPSOs could be operating in the Gulf of Mexico. ABS, with its 50 years
experience in the marine industry, has evolved from its solely-vessel-classification role to more involvement
in design / construction / maintenance technology. Introduced here are several guidance documents / services
offered, or recommended, by ABS that can assist companies planning on entering this growing market in the U.S.
Gulf, and elsewhere.
The presentation comprises two parts. Part 1 overviews
key guides / management systems / analytical tools, including: 1) the Asset Integrity Management System (AIM);
2) SafeHull analysis tool; 3) Rules and Risk-Based Inspection (RBI); 4) three guides for building / classing:
floating production installations, offshore facilities and pipelines / risers; and 5) ABS SEAS
Site-specific environmental analysis system. A comprehensive set of guidance notes on Application of Synthetic
Mooring Ropes is introduced.
Part 2 will continue discussions on maintaining
integrity through: human factors, 3-D visualization, surveys / inspection, risk analysis tools, regulatory /
safety compliance, electronic data management and owner / class society-cooperation.
Introduction
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Industrys first contract for an
integrated, risk-based inspection for the Petrobras P-35 FPSO moored in Campos basins
Marlim field was secured by ABS Group of Houston. This is the first RBI for an entire floating
structure, including both marine and plant considerations. Photo by Geraldo Falcao. |
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While industry eagerly awaits a final decision from the
Minerals Management Service (MMS) on use of floating production / offloading storage (FPSO) units in the U.S.
Gulf of Mexico (GOM), operators and service companies alike are actively considering strategies for deepwater
development that previously were not feasible.
Distance from shore, distance from infrastructure and sheer water depth have stymied development plans
in recent years.
But within a short time, several deepwater fields
many widely spread and some within massive canyons along any seabed route, making pipeline transportation
prohibitive may become economic using FPSOs for development. In fact, within the next decade, some 50
FPSOs may operate in the GOM in water depths up to 10,000 ft, with the first unit expected to be permanently
moored within three years.
As an important point, the availability of FPSOs
and shuttle tankers for transporting production to U.S. markets may facilitate an operators
ability to secure optimum pricing for quality, deepwater production without the possible commingling of oil
from shallow-water reservoirs.
Most, if not all, of these FPSOs will be newbuilds,
purpose-built to address both regulatory issues and field economics. While exciting and certainly technically
feasible, significant issues remain unresolved, including:
- How best to handle gas, as the MMS will not allow
flaring and only minimal reinjection
- Clarification from the U.S. customs Office as to
what flag FPSOs will fly, as the agency has not ruled on the permiting of foreign-flagged FPSOs (it is
understood that lobby groups are proposing these vessels should be built in the U.S.)
- Personnel mandates
- Environmental impact of shuttle tankers carrying oil
to U.S. ports particularly if they are not of the same configuration and manning specs as those
studied in the MMS Environmental Impact Statement (EIS) and its Comparative Risk Study
- Manning and qualification requirements for
permanently moored and disconnectable FPSOs
- Operational requirements for the lightering process
- Clarification of requirements for design,
construction and periodic inspection of U.S. and foreign-flagged FPSOs.
- Whether the MMS or Coast Guard will require a
standby vessel for an FPSO.
Further, to what extent, if any, will the Coast Guard
or MMS require oil-spill containment and removal of equipment beyond current requirements. And to what extent
will FPSOs be double hull.
Industry Guidance From ABS
ABS certainly is not in a position to answer the
questions posed by the above list of issues. However, as a class society with 130 years experience in
the marine industry including more than 50 years in the offshore industry and 47% market share
in classing FPSOs, the Bureau is in a unique position to offer industry guidance in understanding how FPSOs
can work efficiently and safely in the Gulf of Mexico and worldwide.
Additionally, ABS is well suited to assist industry in
its interface with regulatory bodies. With regard to FPSOs operating in U.S. Gulf waters, at least four U.S.
regulatory groups will have an impact: MMS, USCG, U.S. Customs and the U.S. Labor Department (regarding
manning requirements). ABS has extensive experience in managing the interface between these groups and, in
some instances, even acts on behalf of the USCG via federal codes NVIC 10-82, 10-92 and the Alternative
Compliance Program.
Further, ABS is assisting MMS with a recently
commissioned risk assessment for FPSOs to help the regulatory body and industry understand key hazards and
risks associated with these "novel" types of facilities. Results of this assessment will likely
provide a basis for development of regulations concerning use of these mobile production systems in the GOM.
ABS the "Bureau" is a participant, and ABS-affiliate EQE is a facilitator for the study.
And while FPSOs are a relatively "new"
phenomenon in U.S. waters, the structures are successfully used elsewhere in the world, making their use
attractive to operators eager to develop deepwater GOM discoveries. FPSOs are technically feasible in any body
of water; however, adherence to appropriate standards / rules is a must to ensure safe operations and
environmental protection.
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Maintaining asset integrity in the most efficient
way possible is a fundamental goal of most sophisticated owners. |
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Asset integrity management.
Further, regardless of an FPSOs physical location, operators have a critical need to protect
their floating assets throughout their life cycles from a variety of external and internal hazards. ABS
recommends an Asset Integrity Management System (AIM) to ensure that all facets of FPSO use are addressed, and
in complete accordance with regulating bodies.
ABS and its affiliated companies employ modern "risk"
tools to assist owners in establishing / maintaining vessel integrity from early design, during construction,
through safety compliance management and through inspection / maintenance. An organization responsible for
asset management integrity requires:
- Continuity of information throughout FEED (Front-End
Engineering and Development), design and construction for ready access in the future
- Worldwide resources and information systems
- Established feedback system in failures, i.e.,
incidents, accidents and historical information, and
- Technical expertise applied with professional
wisdom.
Elements of integrity management include:
- Design
- Standards
- Station keeping
- Human factors assessments
- Construction
- Survey inspection
- Vendor coordination
- Risk analysis tools
- Regulatory compliance
- Safety compliance management
- Inspection and maintenance
- Electronic data management systems
- Cooperation between owner / class society.
Combining these components into one "intelligent
system" is critical to efficient operations and enhanced safety. Effective management using AIM requires
a significant Information Technology (IT) network, incorporating a developed infrastructure of databases,
software and information systems.
A traditional asset integrity system is often limited
to brief annual and special surveys undertaken by class society surveyors, or similarly qualified certifiers
of contractors. This system confirms that structural / mechanical fitness-for-purpose requirements (according
to class rules, or published standards) have been met. Using AIM, however, owners and operators gain an
understanding of additional internal, external and systems hazards not covered by the rules.
Maintaining integrity of the asset in the most
efficient way possible is a fundamental goal of most sophisticated owners. An asset integrity management
system gives a comprehensive overview of issues and leads to informed, life-cycle management decisions.
ABS involvement in asset integrity management
began in 1947 with the industrys entree into offshore. Starting at that time, ABS role as a class
society called for certification / classification of platforms all over the world. Although it is very
difficult to quantify the safety benefits of certification and classification, there is ample evidence of
problems identified during the process at design / construction stages which would have had major implications
for cost / production as well as safety had they gone undetected.
The industry has good experience in coping with
fixed-platform systems, which evolved from land-based systems. The transition with the complications
that arise when production equipment is placed on floating marine systems has caused concern.
Construction developments, operations as a site-specific vessel and regulatory approvals have occasionally
been tortuous for both owner and operator.
There are, equally, a number of areas where good
initial planning can lead to a methodology which vastly improves the ability to easily manage a vessels
integrity throughout the FEED / design / construction processes, and throughout its entire life cycle. The
life cycle of a floating production system includes:
- FEED
- Detailed design / procurement
- Plan approval
- Construction
- Transportation to site
- Commissioning / start-up
- Repair / maintenance
- Periodic surveys
- Upgrading / modificatio
- Life extension
- Decommissioning, and
- Disposal.
Asset Integrity Management services begin at the
conceptual stage and provide informed life-cycle support until decommissioning. Maintaining integrity begins
at the design stage, or even prior to that with a full risk analysis of the facility and the intended
operation. By applying an in-depth understanding of the vulnerabilities to both natural and man-made hazards,
future integrity can be maintained. Maintaining integrity over the future requires information on the current
situation and as production goes forward. Even still, owners re-assess operations with the constant question,
"Is this the best that it can be?"
Design / maintenance
involvement. ABS has progressively evolved from its original purpose of "classifying"
vessels to being more intimately involved in design / maintenance as well as vessel construction. As
technology developed, ABS progressed the rules to the point where the asset integrity of structural /
mechanical components was assured through rules compliance.
In 1993, ABS revolutionized ship design with its
SafeHull analysis tool. Now, primary design is completed with automatic code checking direct within the
same software package. In the last three years, ABS has developed a system for asset integrity management for
floating production / offloading systems. One of the developments arising from that decision was to extend the
SafeHull concept to include SafeHull for shipshape FPSOs operating in site-specific weather conditions. In
concert, SafeNet was extended to the offshore market.
Maintaining integrity has two parts. The first calls
for maintaining vessel integrity for safety of life, property and the environment this is traditionally
the role of ABS the "Bureau," which handles this with its class infrastructure. Class, however,
implies a "minimum industry-acceptable" standard. Working the issues to a company-specific or
different standard is not easily accomplished through the class system. Nor does the class system generally
deal with issues that might lead to downtime, unless safety of life, property and the environment are also an
issue.
For flagged FPSOs, class is a basis for flag-state
requirements. If, indeed, the vessel is neither classed nor flagged, then coastal-state regulations
which are similar to class apply. If the owner is intent on its own standards, and several are, then
deciding which standards are to be used, how they integrate together and how they can be shown to comply with
regulatory agencies can be a chore.
The second part of this strategy calls for improving
the integrity on: owner / operator issues to owner-imposed safety levels; issues not covered by class and
regulation, such as downtime and business interruption; and on-site or vessel-specific issues not covered by
rules or standards. On the last item, ABS has embraced systems checks and is developing its basis toward
risk-based rules and Risk-Based Inspection (RBI).
An ongoing program is necessary and prudent, and ABS
affiliated companies consult with owners to determine an appropriate level of ongoing inspection and / or
surveying to comply with an owners, and other, requirements. As ABS moves toward RBI, this opportunity
may offer more allowance for the "owners system" to reap the benefits of class, while
selecting a system of compliance within the intent of classification.
Maintaining Integrity By Design
ABS has developed technology to specifically look at a
vessels history prior to its going into service as an FPSO. For shipshape vessels, ABS SafeHull
proprietary program is used, together with weather data, to look at the trading history of a vessel and
determine approximate extent of theoretical fatigue at the point it goes into FPSO service.
Since the loadings are somewhat different for an FPSO,
and weather data is somewhat more precise for the intended location, ABS has developed SafeHull for FPSOs, to
determine design suitability for a particular site-specific location. As corrosion is an ongoing problem with
FPSOs because ballast tanks are filled and emptied far more often than those of a trading tanker
this issue is significant. Fortunately, this condition is one of the variables that can be anticipated and
input into SafeHull for FPSOs data when delivering the required scantlings.
Fatigue is a critical issue. The costs of taking an
FPSO offline for repair is enormous, so proper analysis must be conducted upfront to ensure the lightest, yet
most robust structure possible. This point can be made for every element of an offshore production system,
from moorings to risers to control-room design.
Through the promotion of research / participation in
joint-industry studies, understandings of the failures are better known. ABS has a reporting system to
identify problem areas of all vessels, including FPSOs, so that designs / modifications can be enhanced. In
some instances, a more robust "first principles" approach may be recommended for instance in
the case of innovative designs.
While FPSs are site-dependent structures, it is
anticipated that these vessels may very well become more mobile and require the same kind of checks used for
the MODU community to confirm each site.
Maintaining work pattern integrity for the FPS may
depend on the ready ability of the owner / operator to re-assess the suitability for an existing FPS at a new
site. With records kept in a suitable AIM system, the historical record can be readily retrieved and
evaluation of another specific site quickly carried out.
Three New Standards Guides
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First floating storage and offloading (FSO)
unit for Gulf of Mexico installation, the TaKuntah, was classed by ABS in 1997.
Owned by MODEC (USA) Inc., the converted tanker was installed on Pemexs Cantarell field in July
1998. |
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As the oil / gas industry ventures into ultra-deep
waters, floating production systems are becoming an increasingly important field development option. The
development of appropriately safe standards for cost-efficient design, fabrication and operation of floating
production storage (FPS) and offloading (FPSO) installations is critically linked to the success of deepwater
opportunities. For this reason, ABS recently launched a suite of three guides that bring technical clarity to
efficient development / use of floating production systems worldwide. These are intended to help the offshore
industry address risk-management / integrity-maintenance issues associated with deepwater development. The
guides are,
ABS Guide for Building and Classing: 1) Floating Production Installations; 2) Facilities
for Offshore Installations; and 3) Pipelines and Risers.
Encompassing the experience / knowledge of some 100
floating production / storage vessels which ABS currently has in class, the guides provide design criteria for
assessment of realistic loads, comprehensive design analysis tools, a consistent and common basis for FPSO
design / evaluation and opportunities for risk-based alternatives. The long-term benefits include reduced risk
of structural failure, lower life-cycle maintenance / repair, and an improved ability to predict facility
performance in a frontier environment.
Floating production
installation guide. This is the first such guide to match hull design with field performance, and
it delineates design criteria necessary for a site-specific vessel from requirements for tankers classed for
unrestricted service. Until now, the requirement for ship-type FPSOs was that the vessels hull satisfy
all strength requirements for ocean-going tankers in unrestricted service.
But many FPSOs are located in areas where
environmentally induced loadings are far below the level used to define "unrestricted service for
tankers." The guide also represents improved design criteria for vessels operating in environments where
expected loads are more extreme than for trading tankers, thus enhancing vessel safety.
From a safety viewpoint, ABS and industry are now
better equipped to determine site-specific vessel requirements which will provide more safety in harsh
environment areas while allowing planners to design with local, extreme-weather criteria in mind. This
development is a huge step forward as a technological solution.
ABS SEAS Site-Specific Environmental Analysis
System Module of SafeHull for FPSOs, is a new development. By using the new system, FPSOs can be
evaluated for actual stillwater- and wave-induced loads expected during transit, trials and while stationed
onsite.
By using actual wave spectrum and stillwater loads, ABS
is able to obtain the most efficient structure from both strength and fatigue standpoints. Most shipshape
vessels to date have used the North Atlantic trading route as the base requirement.
There are many locations in West Africa and Southeast
Asia where this full requirement is unnecessary, and with the new issue of ABS Rules for Floating
Production Installations, reduction in required bending moment is now allowed.
In the case of an FPSO to be located in a relatively
benign environment, such as the GOM, ABS-required hull scantlings for a newbuild may be rationally reduced
below those required in unrestricted service. In the case where environmentally induced loads are more severe
than those for unrestricted tanker service, again the module will assist the designer in determining: 1) how
much the strength of the hull needs to be increased, or 2) otherwise reduce the loads it may experience.
Further, with a full assessment by SafeHull, owners
will be able to identify "hot spots" or critical inspection areas. This process can form the start
of an RBI program.
Guide for building /
classing facilities. Technology advancements in topside facilities in the last decade have
necessitated a revised ABS Guide for Building and Classing Facilities for Offshore Installations. The
guide incorporates requisite standards for production facilities installed on both fixed and floating
installations, giving operators a clear understanding and increased flexibility of specific
requirements for each type of installation.
The previous version of the facilities guide did not
make this distinction, leaving questions as to appropriate requirements for floating / fixed installations.
For example, the new guide addresses issues such as stresses induced by acceleration forces of floating
installations, for consideration in equipment design. This information is a real contribution to the industry,
particularly as manufacturers move from fixed to floating production markets.
Often an oil company will contract a manufacturer to
construct the process equipment skids but the manufacturer does not know whether the skids are to be installed
on an FPSO, with vertical, horizontal, heave and pitch motions, or on a TLP, which moves much less.
Motions of these floating platforms are very different
and may have unique effects on equipment. In fact, equipment not designed for a particular environment may not
work at its best efficiency and this may even impact safety. The impact on piping by deck flexing, for
example, can be significant.
Design load on floaters needs to consider the stress
induced by attachments to pressure vessels because nozzles connecting to vessels can "snap" or break
if not properly supported. The guide is extensively cross-referenced with existing rules, industry standards
and codes to help clarify application.
Separately, the facilities guide clarifies the use of
firefighting systems onboard floating installations. Fixed platform installations follow standards set down by
the National Fire Protection Agency. Ships and floaters, however, are subject to international codes, such as
Safety of Life at Sea (SOLAS). The facilities guide addresses the interface between marine and industrial
systems, giving clarity for the application for appropriate rules and codes.
The guide offers a method of integrating standards for
topsides with standards for marine systems in an appropriate safety system. For instance, hydraulic power
services, typically for marine support functions, must be designed to meet Steel Vessels Rules and Power
Piping Code (ASME B-31).
A similar system provides the process control service,
which is governed by the Chemical Piping Code (ASME B-31.3), set by the American Petroleum Institute.
The industrial systems, including the process support mentioned above, tolerate higher risk but typically
require a high level of inspection. Confusion arises where both functions are served by the same system.
The facilities guide also incorporates risk-based
criteria for alternative use of risk methodology. The approach is derived from OSHAs Process Safety
management and the U.S. Environmental Protection Agencys Risk Management Program regulations, opening
the door to risk-based design.
The flexibility allows risk analysis to be tailored to
risks associated with particular equipment design, and addresses areas of concern on an item-by-item basis.
From a commercial viewpoint, the owner also can utilize risk rather than prescriptive rules to determine how
and where resources are allocated.
Guide for pipelines and
risers. This ABS publication provides technical documentation for the design, fabrication,
installation and operation of offshore pipelines and risers. Issues addressed include design, materials /
welding, testing / survey, and inspection / maintenance.
The revised guide reflects current industry practices
and technology developments, including limit-state design criteria, structural reliability analysis, risk
management and assessment of corrosion, dent and crack-like defects. The guide incorporates the latest
research for strength and fatigue analysis for rigid pipelines / risers, thereby facilitating cost-efficient,
reliable design methods for deepwater installations.
Because offshore design / fabrication is often unique,
or of a prototype nature, it is rare that prescriptive requirements alone will be both applicable and
sufficient. ABS offshore engineers work in concert with surveyors and industry / regulatory bodies to ensure
that safety concerns are fully satisfied to at least equivalent safety criteria. The risk-based alternative is
a technique using sound engineering practice to avoid emotional criteria.
This latitude gives the industry improved access to
risk-based design, supported by industry-accepted risk assessment techniques and bringing increased
flexibility for deepwater applications. For the risk-based process, ABS is involved from the conceptual phase
to address hazard operability (HAZOP) and hazard identification (HAZID) issues. The commercial benefit of this
approach is that these standards allow operators to optimize dollars / resources by focusing capital on the
technical areas of most concern for maintaining integrity through the life of the asset.
Station Keeping, Synthetic Ropes
In maintaining the integrity of floating production
systems for deep water, station-keeping system integrity is crucial. This issue may have more significance to
regulators in areas with tropical revolving storms, where loads are high, or where there is a significant
platform infrastructure creating increased risk should an FPS break loose.
As industry ventures into deeper water, synthetic
mooring systems are expected to offer improved efficiencies for optimum field development schemes. Such
innovative advances must be tempered with the wisdom of industry knowledge at the time. With this in mind, ABS
has delivered a comprehensive set of Guidance Notes on the Application of Synthetic Ropes for Offshore
Mooring.
The availability of synthetic materials and alternate
mooring systems is extending the economic capability of existing floating technology into deeper waters. By
incorporating synthetic rope into current-day, deepwater technology, a floating production facility can
support more revenue-producing equipment as the industry readies for ultra-deepwater basins.
The synthetic rope guidance notes address this issue
and other fundamental industry concerns, including non-linear stiffness or behavior, minimum tension
requirements, creep phenomena and effective handling and storage of rope.
To maintain the integrity of these mooring systems,
further research is needed on long-term effects, and the ability to detect, in-place, system deterioration. On
this issue, maintaining the integrity is best achieved through funded research projects.
Coming in Part 2: Continued
discussions on maintaining integrity through: human factors, 3-D visualization, surveys / inspection, risk
analysis tools, regulatory / safety compliance, electronic data management and owner / class
society-cooperation.
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Part 2 |
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