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					                              OLF FPSO Project 2002




                   A summary Report on
   FPSO Lessons Learned, gathered
 from 5 Norwegian FPSOs - May 2002

                           20 September 2002




           Prepared for the Norwegian Oil Industry Association, OLF




                      The Offshore Management Centre,
                     Robert Gordons University, Aberdeen




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                           OLF FPSO Project 2002




Preface


In 2001 OLF formed an Floating Production, Storage and Offloading (FPSO)
Experience Transfer Workgroup. The group’s objectives are to facilitate
experience transfer between Norwegian FPSO operators and potential
operators to reduce capital and operating costs and improve overall
effectiveness.

A decision was made in 2002 to interview Operating and Project staff
involved in the 5 Norwegian FPSOs. The contractor RGU had been involved in
a similar study in the UK and was therefore able to make comparisons
between UK and Norwegian experience. A team from RGU, OLF and Marintec
conducted the interviews and prepared the interview summaries. The team
consisted of;

            Mark Capsey (RGU)
            David Llewelyn (OLF)
            Erik Dyrkoren (Marintek)

The OLF workgroup members provided the essential guidance and support for
the interviews and can be contacted if further information is required. The
workgroup members were;

            Torbjørn Huslende (ExxonMobil)
            Nils Kjær (Norsk Hydro)
            Stig Mjøen (Statoil)
            Erik Vogsberg (Enterprise/Shell)




            Stavanger 20.9.02

            David Llewelyn
            Workgroup Facilitator OLF




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                             OLF FPSO Project 2002



                                  Contents


1.          Executive Summary                                              3

2.          Introduction                                                   4

3.          Aims and objectives                                            4

4.          Methodology                                                    4

5.          Key Issues Raised and Resolved / Lessons Learned               6

6.          Industry Challenges                                            17

7.          Norwegian FPSO Successes                                       23

8.          UKCS FPSO Lessons Learned                                      25

Appendix1   Home Page                                                      27

Table 1     Summary of Key Issues, Lessons learned and Challenges          28

Table 2     Database of Norwegian FPSO Key Issues & Lessons Learned        37

Table 3     Norwegian FPSO Successes                                       66

Table 4:    Most widely reported issues/problems relating to UKCS FPSO’s   67

Table 5:    UK FPSO Checklist                                              68




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1.         Executive Summary

     In April/May 2002 the Norwegian Oil Industry Association (OLF) initiated a research
     project to collect specific lessons learned from the operation of five Norwegian
     Floating Production Storage and Offloading vessels (FPSO’s).

     Using a structured survey tool the project team interviewed 23 representatives of
     ExxonMobil, Norsk Hydro, Statoil and DNV.

     Interviewees included 3 OIMs, 5 Maintenance Superintendents, 2 Production
     Supervisors, 2 Operations Superintendents, 6 FPSOs specialists, 4 Project
     Management specialists and 1 DNV representative.

     The findings were jointly written up by the project team against 64 topics and
     categorised for importance and underlying causes.

     The major output of this exercise to date is the creation of a comprehensive
     database of issues and problems that the Norwegian FPSO sector has faced up to
     and resolved and the key lessons learned.

     The most significant of these issues and related lessons learned are summarised in
     Chapter 5 and the Appendix Table 1.

     More comprehensive details of the issues/problems, remedial actions and lessons
     learned are presented in the Appendix, Table 2.

     Approximately 350 FPSO related issues/problems were reported. Where the primary
     underlying cause was identified the percentage number of attributions were design
     issues (63%), operational issues (16%), construction issues (12%), and
     commissioning issues (9%). It would appear that during the first 18 months
     problems are often down to poor construction and commissioning after that issues
     are usually attributable to design.

     Respondents highlighted 21 significant challenges that the FPSO community faced.
     It is recommended that each of these issues presented in Chapter 6 and
     Appendix, Table 1 should be the subject of further consideration to determine
     the best way to jointly overcome that challenge.

     Most lessons learned arise from the experience of problem resolution. Although
     selected feedback on Norwegian FPSO successes is presented in Chapter 7 and
     Appendix, Table 3; this was not the primary emphasis in the information collection
     and respondents feedback.

     A similar research exercise into lessons learned was undertaken for UKCS FPSO’s in
     2001. In Chapter 8 and Appendix Tables 4 and 5 some general and selected
     links have been drawn between the Norwegian and UK experiences.




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2.         Introduction

The Norwegian Oil Industry Association (OLF) initiated this preliminary research
exercise. It was undertaken by David Llewelyn (OLF Project Manager, Stavanger), Mark
Capsey (General Manager, Offshore Management Centre, Robert Gordon University,
Aberdeen) and Erik Dyrkoren (Research Engineer, Norwegian Marine Technology
Research Institute, Trondheim).


3.         Aims & Objectives

The purpose of this joint industry initiative has been to collect lessons learned from the
experiences of operators of Norwegian Floating Production Storage and Offloading
vessels (FPSO’s). Information was collected from three operators responsible for five
FPSO’s; ExxonMobil (Balder & Jotun A), Norsk Hydro (Varg) and Statoil (Asgård &
Norne) and the DNV. The objective has been to ensure that project and operating
experience is not lost but that generic lessons learned are widely disseminated to allow
continuous improvement, to assist common problem resolution and to seek to minimise
repetition of mistakes.


4.         Methodology

The project team together with contributions from the participating company
representatives identified a suite of categories of FPSO issues for investigation. These
were formatted into a survey tool under seven main headings: Hull & Marine; Turret;
Layout; Project Management; Operations & Support; Codes/Classification; Manning &
Safety.    The survey tool invited respondents to identify issues/problems related to
FPSO’s, to rank their relative level of importance, and to identify the underlying cause as
either design, construction, commissioning or operational related. Where remedial
actions had been undertaken comments on the effectiveness of these were invited.
Finally respondents were asked to comment on any lessons learned.

Experience suggests that the most valuable feedback is derived from respondents who
have had a chance to consider the subject matter in advance. Therefore the survey tool
was issued for completion to the interviewees some days prior to their formal interviews
as a catalyst for meaningful discussion. It was observed however that the majority of
participants had not completed the form before their interview, but preferred to
‘brainstorm’ on the day.

Between 22-26 April 2002 the project team met with and interviewed 23 representatives
of ExxonMobil, Norsk Hydro, Statoil and DNV in Stavanger, Sandvika and Stordal plus a
videoconference with Harstad.




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                                 OLF FPSO Project 2002


The project team would like to thank all the participating companies for the excellent
timetabling arrangements and the useful feedback supplied by all their representatives.


Once reviewed the interviewee’s comments were collated by FPSO Company. These
were then returned to each participating company for any additional feedback
comments and amendments. To maintain client confidentiality in this final report all
indications of information source including specific FPSO references and mentions of
vendors have been removed.

Part of this project has also involved linking the Norwegian FPSO experience with
information collected by the Robert Gordon University, Offshore Management Centre for
a UK FPSO research exercise conducted in 2001.

In this exercise a substantial amount of information related to FPSO operations has been
gathered. To best review the data it is recommended that the Appendix be
viewed on-line. A large number of hyperlinks have been created to assist users to
move from one data set to another. The Norwegian interview notes have been
evaluated and synthesised by the project team and compiled into a simple MS Excel
database. From this considerable information set a summary of the key issues, lessons
learned and challenges still to be faced have been compiled in Table 1. The bulk of the
raw data on which this interpretation is based is presented in Table 2. Where given,
insights into the perceived successes of Norwegian FPSO projects are documented in
Table 3.

The most widely reported issues/problems relating to UK FPSO’s are presented in Table
4. A particularly useful output from the UK research exercise was a checklist of design,
construction, commissioning and operational issues, which if acknowledged might assist
avoidance of decisions, and actions, that potentially could lead to problems during start-
up and operations. A version of this is reproduced in Table 5 with hyperlinks to the
Norwegian case study material.




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5.         Key Issues Raised & Resolved / Lessons Learned

In identifying issues/problems faced in the operation of their FPSO’s, respondents were
asked to rank them from 0 (not an issue) to 4 (critical issue) with respect to their overall
level of importance. Summaries of those issues perceived as critical (4), major (3) and
moderate (2) are given below and have also been highlighted in the appendix.

Hull & Marine

A total of 172 hull and marine related issues/problems were reported. Where the
primary underlying cause was identified the number of attributions were design issues
(97), construction issues (20), operational issues (16) and commissioning issues (3).


Green Water (Critical)
Green water has affected 4 out of 5 FPSO’s. Waves over the bows have damaged
stairways and broken accommodation windows. Waves along the side have damaged
ancillary equipment including fire stations, cable trays and pipework. Model testing and
environmental predictions appear to have been inadequate to allow designers to
eliminate these green water effects.

Retroactive repairs/redesign including the fitting of side panels, raising bow walls and
moving sensitive equipment appear to have reduced the problem. In some cases cargo
limits have been imposed. A joint North Sea workgroup including the authorities and
classification societies has now led to a greater understanding of green water design
requirements.


Hull - Strength (Critical)
3 out of 5 FPSO’s have experienced internal cracks between tanks. Cracks were
detected through minor leaks. No leakage has occurred outside the hull. In each case a
programme of inspection and repair has been initiated. This involves taking the affected
tanks and adjacent tanks out of service, making a manned entry and after cleaning,
fitting appropriate stiffeners.

Conventional hull design and basic fatigue analysis has been unable to eliminate FPSO
hull cracking in service. While this is not unusual for trading vessels the operational
problems and costs of offshore repair make this situation undesirable. Future hull
designs should make use of fatigue analysis in all critical and high-risk areas with
construction detail subject to high levels of control.



Accommodation (critical)
The FPSO accommodation has insufficient beds (4 out of 5 FPSO’s). The situation is
worsened by recent proposals from the unions that two people should not sleep in the



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same cabin simultaneously. This lack of beds seriously hampers summer maintenance
programmes and delays major repairs or upgrades.

The economic impact of limited accommodation on operations and project (start-up and
upgrades) is likely to be significantly greater than the cost of the extra beds and
facilities. Future FPSO’s should have 100+ usable beds and/or have provision for
temporary expansion.


Ballast & Cargo Pipework (Major)
Construction standards for cargo and ballast pipework have proven inadequate for
FPSO’s. Problems have included weld failures, leaks and corrosion. GRE pipework has
had to be reinforced due to inadequate jointing.

Since experiencing a number of failures in Cargo/Ballast pipework built to marine
standards in the Far East, DNV have tightened their inspection standards. This combined
with more attention to material selection; inspectability and access should mitigate the
problem.


Corrosion & Coatings (Major)
Coatings are required in the base of tanks to minimise corrosion from free water. If this
coating fails or cracks SRB can build up causing significant pitting. This is a very difficult
area to inspect, so damage might become quite extensive before detection.

Operators should have an ongoing inspection programme of tank bottom coatings and
wall thickness measurement. Highest risk areas are slops tanks, areas under solids build
up and locations where coatings may crack as a result of hull strains.


Cranes (Major)
The choice of cranes - solid boom for 4 out of 5 FPSO’s was not optimum. These heavily
built booms are strongly affected by the wind and due to their weight, are insufficiently
responsive when offloading a supply vessel or for working on equipment. The general
view is that these cranes were not designed for active load handling but for in-port
offloading.

A number of upgrades have been made or considered - increased hydraulic power,
installation of coolers, emergency power pack, boom arc limit switches. However these
modifications have only partially solved the problem.


Helicopters (Major)
The forward positioned accommodation and helideck on all Norwegian FPSO’s is not
optimum for helicopter landing - misaligned approach, no forward visual reference-point
and increased vertical movement (cf. aft helidecks). However it does have the
advantage of clean air (no vessel-induced turbulence and no take off obstructions.



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Installation of large helidecks on certain FPSO’s and provision of high-powered lighting
has helped pilots. FPSO’s can often turn across the wind to facilitate a 45-degree
approach upwind. Reliable weather and heave monitoring equipment should always be
selected. Future FPSO Helidecks should be designed and specified in consultation with
helicopter operators to take account of lessons learned on existing FPSO’s.


Hull Capacity (Major)
Typical shuttle tanker (ST) capacities are 900,000bbls. For commercial reasons and to
make best use of the ST, Operators have wanted to fill the shuttle tanker. In several
cases the storage capacity of the FPSO requires the ST to wait and complete loading
with a second hook up. As well as risking failure to connect due to weather, the extra
waiting time is expensive.

The cost benefits of increased FPSO storage volumes should be considered at the
earliest opportunity in the design phase. It is likely that matching storage volumes to
the size of the planned shuttle tanker will prove the most cost-effective option.


Inert Gas System (Major)
One FPSO was designed with Hydrocarbon blanketing to replace inert gas. Following
successful proof of concept, this is now being extended to others. As well as eliminating
venting or flaring, it reduces use/maintenance of the inert gas generator.

This newly introduced technology has proven successful. Note: a key aspect of
hydrocarbon blanketing is O2 detection. This instrumentation must be kept in service
and backed up at all times.


Moorings (Major)
Different approaches have been taken by Norwegian FPSO’s. Use of individual anchor
winches has the advantage of facilitating winter installation, allowing active
management of the mooring system and enabling movement of the chain wear point.
The permanently stopped design is simpler with reduced maintenance and lower capex.

It is not yet known if wear will be a problem for the permanently stopped design,
however there is as yet no straightforward method to inspect the top of the chain and
service the fairlead. Good experience with such a design may lead to increased use of
this lower cost approach. To date (other than minor drilling rig damage - better
monitoring is required here) there have been no problems with the mooring lines and
anchors.


Motion Assumptions (Major)
Motion has not been a significant problem for production regularity in Norwegian
FPSO’s. The key has been selection of effective level control instrumentation.
Longitudinal separator placement has been successful. One FPSO was able to maintain
full production in 12m significant wave heights.


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However operating experience for at least one FPSO has shown roll limits to be under-
estimated. This has required an upgrade of the topsides fatigue design.


PAU Structures, Supports & Interfaces (Major)
There have been a number of problems with PAU supports. These include excessive
vibration of reciprocating compressors and pumps transferring noise too the hull, flexing
of compressor supports, excessive PAU stiffness leading to cracks in the deck, pipework
stresses due to moving independently from the PAU.

PAU design, supports and associated pipework are a critical area. Design must take full
account of vessel movement, machinery vibration, vessel role, wind and live liquid
loading and construction tolerances.


Power Generation (Major)
Each FPSO has a different engine combination. Wartsilla diesels while reliable and
flexible have the disadvantage of design challenges for dual fuelling, high levels of
maintenance and noise. LM 2500 engines have been the most successful for FPSO’s.
The larger and newer LM 6000s have proven inappropriate for offshore use with variable
loads (from thrusters) and the demands of low nox emissions and dual fuel use.

3 out of 5 FPSO’s have either inadequate power or incorrect engine sizes for efficient
running. The best solution seems to lie in smaller gas turbine packages in combination
with a large back-up diesel generator. Gas turbines also provide ample waste heat for
crude heating. The use of reciprocating diesels for main power has only been considered
appropriate for smaller FPSO’s.


HVAC (Moderate)
There have been a number of examples of poor HVAC design. The most serious was
the level of noise, which failed to meet Working Environment rules. Modifications after
construction are expensive and disruptive. Other problems are balancing difficulties,
lack of external air locks; poor access for maintenance, stuck dampers and excessive
dryness in the air.

HVAC design is a key area of design as a safety critical system. A contractor familiar
with North Sea conditions and Norwegian Working Environment legislation should
manage the work.


Selection of Marine Equipment (Moderate)
Shipyards will normally fit butterfly valves on penetrations through the hull, however
their life is limited and they are easily damaged by marine growth. On FPSO’s these
should all be replaced by gate valves, and provision made to blank these off externally
for service



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Workshops (Moderate)
Workshop design and locations vary on the FPSO’s. The most successful are accessible
via forklift, on the same level and close to stores, well equipped with mechanical
handling equipment, separate from the accommodation (for noise) and in a safe area
allowing welding (forward).

Getting the workshop design right is important for maintenance efficiency and crew
morale. The working environment, access and conditions in the workshop will reduce
repair costs, as the crew becomes confident to repair and service equipment on board.



Turret

A total of 30 turret related issues/problems were reported. Where the primary
underlying cause was identified the number of attributions were design issues (15),
operational issues (5) and construction issues (2).


Turret Location (Critical)
The turret location is a key design issue. With the turret at greater than 75% of overall
hull length from the stern, the vessel weather-vanes free. At around 65% (4 out of 5
FPSO’s), thrusters are required to maintain/control heading. The controlled heading
FPSO’s have the advantage of being able to lock the turret and thereby reduce bearing
and swivel wear. However this places a demand on the thrusters (which are safety
critical) and the crew to mange turret repositioning.

Experience to date from the single Norwegian FPSO with a free turret indicates lower
maintenance and crew involvement than with the other FPSO’s. In addition that FPSO
has managed to achieve adequate safety of the accommodation forward of the turret,
by using a firewall. Current experience suggests that a free turret with swivel and
thrusters used for offloading only, results in the lowest Opex.


Turret Design (Critical)
Three types of turret bearings are used by the 5 FPSO’s. 2 out of 3 types have been
troublesome. The wheel and rail type have proven unsatisfactory due to high point
loading from the wheels, excess construction tolerances, vessel deflection, poor rail heat
treatment leading to surface cracking and inadequate wheel lubrication. The hydraulic
turret bearings have suffered from pad wear, high starting friction, gripper failures,
hydraulic imbalance and difficulty to access and repair components.

Turret bearing design has evolved over time. While simple rails and wheels have proven
inadequate, heavy duty rails and multiple bogies with rubber pads to spread the load
have proven an effective solution. Hydraulic pads were selected to deal with high
mooring loads on a large turret. While this has been effective leading to no downtime,




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maintenance has been excessive. A key learning from all designs is the need to make all
components easily serviceable and replaceable.


Risers (Major)
Risers are a critical component of the FPSO system. Damage to the outer sheath and
seawater ingress can reduce fatigue life significantly. Gas permeation can have
unexpected effects including collapse, and HP gas flow can cause vibration or loosening
of the inner carcass. To date however, there have been no catastrophic failures of risers.

Good riser design and operational management is a key success factor. Monitoring
systems, the ability to flush the annulus and protect the riser from damage, particularly
on installation are needed to ensure long and trouble free life.


Swivels (Major)
Overall the performance of swivels on the 3 FPSO’s has been good. There have been no
significant leaks; the only major problem was two failures and an explosion in the oil
filled 11KV-power transfer swivel. This was due to water entering the insulation oil
medium.

Initial worries about swivel reliability have now been reduced. However, only one FPSO
has continuous swivel movement (free turret) and this has only been in service two
years, so long term wear concerns and repair methods remain untested.


Drag Chains (Major)
2 out of 5 FPSO’s have drag chains as an alternative to a swivel. Specific problems
experienced include hose and electric cable failure due to wear from bending, wear pads
worn out, difficulty of access, and damage caused by running into the end stops. In
addition the drag chain limits the free rotation of the vessel requiring thrusters to be
serviceable at all times.

While simpler than swivels, high maintenance and operability problems have indicated
that swivels would have been a better option. This is endorsed by one FPSO where the
operator has elected to replace the gas transfer hose with a swivel.




Layout

A total of 19 layout related issues/problems were reported. Where the primary
underlying cause was identified the number of attributions were design issues (12),
commissioning issues (2) and operational issues (1).




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Layout (Critical)
The layout of equipment on an FPSO is a critical design phase. Concerns noted include
placing main generators too close to the accommodation, poor mechanical handling
solutions, exhaust and flare radiation problems, module overcrowding when others are
very spacious, poorly placed vents, access and escape routes restricted by cable and
pipework, poor workshop and store locations.

It is recommended that when a basic FPSO layout is outlined more time is spent with all
interested parties both informally and through formal design reviews to ensure the best
compromises are achieved. Relevant specialists must carefully consider all Capex, Opex
and Safety issues.


Vents & Exhausts (Moderate)
All FPSO’s have had problems with cold venting of hydrocarbons tripping the process.
Modifications have involved routing all vents up the flare stack or, on the thruster
controlled FPSO’s, on the downwind side.

More attention should be paid at the design stage to any source of hydrocarbon venting.
This requires a significantly different approach from a trading tanker. Minor releases
can be cold vented but lines need to be located and sized to minimise any risk of
explosion or tripping gas detectors under any weather conditions.




Project Management

A total of 29-project management related issues/problems were reported. Where the
primary underlying cause was identified the number of attributions were design issues
(11), commissioning issues (6) and construction issues (4).


Capex Overruns and Schedule delays(Critical)
On only one FPSO capex over-runs were avoided. In this case contract terms were
followed with minimum change. This kept costs under control, however the Operator
admits quality was poorer than expected and opportunities to improve the design at low
cost were missed. On the remaining projects costs over-ran significantly but the quality
was higher than the original specification and design improvements implemented.

Almost all FPSO projects in the 90s were underbid by the main contractor. The Operator
can either participate actively implementing upgrades when poor quality or low cost
solutions are offered, or impose the contractual terms. In general an optimum balance
can be struck by working with the contractor to maintain quality and provide assistance
to improve efficiency.




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Construction Management (Major)
In several cases the build contract specified functional requirements, however the
design contractor and shipyard were unable to interpret these correctly. In addition they
failed to manage builders and suppliers to adequate quality standards, or to keep within
budget or time schedule.

Functional specifications generally give the yard and designers too little guidance. More
work should be done up front on the selection of key equipment and specification of
quality. In all 5 cases the operator has had to provide significant resources to support
the project or in 3 cases take over responsibility for completing the project.


Project Input from Other Groups (Major)
There is evidence that builders and contractors learn a great deal during projects. There
is therefore a real advantage in building a second or third vessel in a yard, where many
of the original problems have been worked out. However this learning appears to be
short term, as people and teams are often moved to other areas of activity.

There are advantages in repeat orders due to organisational learning, however if
workloads are high, there is the risk that a new team with little experience will have to
start at the bottom of the learning curve again.




Operations & Support

A total of 74 hull and marine related issues/problems were reported. Where the primary
underlying cause was identified the number of attributions were design issues (20),
operational issues (17) commissioning issues (9) and construction issues (4).


Compression
A). (Critical) 3 out of 5 FPSO’s had serious compression problems (gas seal failures,
repeated bundle change-outs and cracked pistons) due to undersized scrubbers and
liquid carry-over. Upgrades, improved instrumentation and online equipment monitoring
solved problems. The cost of these failures which includes; service costs, spares, CO2
tax, substitute diesel fuel, and lost gas export income was substantial.

A number of factors contributed to these problems, poor instrumentation, and vessel
movement reducing efficiency of separation train, liquid hold up in pipes and slugging
and poor performance of internals. It would seem a good investment to install larger
scrubbers than normal to provide a safety factor for unknowns.

B). (Major) Vibration from reciprocating compressors can be a serious problem. On one
FPSO poor mounting of the compressors and failure to fit bellows and flexible hoses has
led to an ongoing sequence of high potential leaks and failures. Vibration has also




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affected the drive motors with isolating pads coming loose and damaging rotors. Noise
is also a problem for personnel.

Reciprocating compressor vibration is a key design issue. Only a competent supplier with
experience of packaging such units offshore should design such systems.              An
independent review of noise and vibration levels is recommended.

C). (Moderate) One FPSO achieved Gas Compression start-up 7 days after first oil. This
is probably an industry record. This was achieved through comprehensive pre-start-up
commissioning work and operator training.

Gas plant commissioning should be fully completed before sailaway. Equipment should
be run on load with simulated gas. Operations staff involvement with commissioning,
use of plant tuning simulators also with a rapid start-up.


Uptime Performance (Critical)
Overall performance has been excellent. 4 out of 5 FPSO’s are delivering 95% or more
of available volumetric production. The 5th is at around 90%. While these figures were
lower in the first 18 months production, regularity has generally exceeded industry
expectations.

There is a lack of fully objective data and it is too early to fully evaluate the success or
failure of different FPSO designs and operating strategies. To date high performances
have been achieved but often at the expense of major modification and/or ongoing
repair programmes. Opex data was not available for the review.

Shuttle tanker / offloading (Major)
FPSO/Shuttle tanker offloading has been very successful. One high potential and one
minor incident occurred out of approx. 1000 offloadings – the first was a contact when
some light structural damage was sustained and the second a rope round the thruster.
Incidents of missed loadings due to weather have also been very few.

Lessons learned include the need to identify contact zones at the rear of the FPSO to
ensure damage escalation risk is minimised, improvements to hose care when sliding in
and out of the shute, better procedures for handling the messenger line and
identification of critical components for maintenance/sparing.


Submersible Offloading Pumps (Moderate)
Many Problems were experienced with hydraulic submersible pumps in the early phases
of operation. Problems were related to debris in the tanks and pipework and pipework
leaks.

Hydraulic submersible pumps are highly sensitive to debris and any weaknesses in the
pipework. This should be an area of special focus during commissioning. Simpler
methods to access and repair submersible pumps should be also implemented.



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Process (Moderate)
There is often inadequate provision for sand and solids in the separation system.
Although wells are predicted to be sand free, when water arrives they often produce
sand. It is also useful to be able to clean up wells directly through the test separator,
which should have sand jetting installed.

Provision for sand and solids’ handling is generally a good long-term investment, despite
optimistic predictions from the reservoir engineers.



Codes/Classification

A total of 16 codes/classification related issues/problems were reported. Where the
primary underlying cause was identified the number of attributions were design issues
(4), and commissioning issues (2).



Manning and Safety

A total of 7 manning and safety related issues/problems were reported. Where the
primary underlying cause was identified the numbers of attributions were operational
issues (3) and commissioning issues (1).


Safety - General (Critical)
There is no evidence that FPSO’s are less safe than other installations. A number of
FPSO’s reported that with a smaller crew than a platform, relationships, communication
and morale are better.

There is evidence that active attention to and reporting of hazards improves safety
awareness and thereby performance.


Crew (Major)
All FPSO’s operate with a base crew of 35-40. This required a number of staff
particularly crane operators and mariners to be multi-skilled. However most FPSO’s
carry typical POB levels of 55-70. This can cause significant problems for major
maintenance or upgrade projects.

A significant realisation has been importance of carrying multi-skilled mariners within
base crew. Their experience is particularly important for emergency situations, cargo
management/offloading and maintaining equipment exposed to sea spray and corrosion.




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                                OLF FPSO Project 2002


Motion effects on people (Moderate)
Seasickness has not been reported as a major problem. People suffer for a day or so
but seem to adapt. Many people use stick-on patches as a cure. It can be more of a
problem however for visiting service personnel, and crews sent out to work in enclosed
spaces such as tank cleaning.

FPSO management must continue to be sensitive to the problem this can pose for
certain individuals. Again this underlines the importance of having a core crew of
mariners on board.




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                                OLF FPSO Project 2002



6.         Industry Challenges

Respondents highlighted a number of challenges that not only they, but also the FPSO
community in general faced.


Hull & Marine

Accommodation (Major)
A means is required to increase FPSO accommodation for short periods (say 2-6
months) for project or major repair/remedial work. The upgrade would have to meet all
applicable safety requirements including the provision of recreation space, lifeboat,
refuge and escape facilities.

The design option selected is likely to be different for each FPSO - these may range
from an additional deck mounted module to beds installed in unused rooms. Lifeboat
and escape facility upgrades will also be required. Close and early consultation with the
workforce will also be essential.


Caisson Systems (Major)
Placement of sea water pumps deep in the hull (forward or aft of the main tanks)
presents three main problems, cavitation when the vessel is at shallow draft or in rough
weather, cost of installation in the hull and difficulties with access and maintenance of
the engine.

An evaluation should be conducted into the practicality of using inboard mounted
caisson installed pumps for delivery of seawater direct to the end user. The advantages
would be reduced pipework, easy access to fire pumps, less cavitation and simpler pump
maintenance and marine growth removal.


Mechanical Handling (Major)
Mechanical handling for all operation and maintenance activities has been strongly
criticised on all 5 FPSO’s. Cranes are not optimum for working on FPSO equipment. "As
built" handling systems for equipment in the hull are often inadequate. In general the
vessel layouts are poorly optimised for equipment handling and storage.

It is suggested that the best practices developed from experience with - choice of
cranes, use of forklifts, layout, storage and landing areas and protection, hydraulic
manipulators, lifting beams and appliances in the hull should be documented in a "code
of practice" so in future contractors can design and optimise handling systems from the
outset.




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                                  OLF FPSO Project 2002


Hull Shape (Major)
Hull shape involves a number of compromises. A sharp bow increases green water as
the hull cuts through the waves, but it reduces mooring loads. However a sharp bow
leaves little space for machinery, reduces storage volumes and increases complexity for
building. The transition zone has also been a source of cracking. Alternatively a blunt
bow increases spray and wave impact and mooring loads.

Lessons have been learned with the compromises in hull shape for harsh environment
FPSO’s. These lessons need to be documented and in combination with improved model
testing and environmental data used to design and specify the optimum FPSO shape for
each situation.


Painting (Major)
All 5 FPSO’s have suffered from inadequate paintwork. The underlying problem is lack of
priority and time allocated to this activity. Quality control of preparation and finishing
has also been lacking. Painting in Singapore has been particularly poor due to the
humid conditions. There has been a serious problem on several FPSO’s with a topsides
paint system failure in Norway - premature thickening of the paint, that has led to
extensive remedial work.

Painting of FPSO’s is a critical area to ensure a low maintenance facility over a long
period offshore. The inability to dry dock the vessel and its limited accommodation
demand that the initial paint finish is to the highest standard. However this work is
often conducted late when the pressure for sailaway is high.      The challenge is to
develop painting technology and methods compatible with project demands and a 20-
year offshore life.


Thrusters (Major)
Service or repair of thrusters is a major challenge, particularly as reliability has not been
as high as expected. Most FPSO’s require thrusters at all times; a failure in winter could
impact safety and production. Most thrusters have to be withdrawn externally and ROV
work is weather sensitive and high risk. Use of FPSO cranes while helpful, is not always
feasible due to thruster weights and position.

Methods for removal and repair of thrusters in field need to be developed and shared.
One solution for the future is that thrusters are not safety critical (this is true of one
FPSO), and thrusters should be designed for internal retrieval and service. This design
has been achieved on one FPSO.


Painting (Moderate)
Painting the hull in the area of the water line will present a challenge as this is normally
done at 5-year dry dock. The vessel can be raised under light ballast however the work,
if required, will be very exposed with no provision for scaffolding.




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                                  OLF FPSO Project 2002


The challenge is to devise a methodology to safely clean, prepare and paint FPSO hulls
at the splash zone while the vessel is on location and in production. The work must be
conducted by a small crew so minimising impact on other summer maintenance
activities.


Tank entry (Moderate)
Entry to tanks for inspection and repair is proving very costly both the time and
resources. Primary problems include tank washing, gas freeing, solids removal, tank and
pipework isolation, and personnel access, repair and recoating methods.

Crude and ballast tanks should be designed to facilitate maintenance. This involves
special provisions for cleaning, venting and access. For existing FPSO’s, tools and
methodologies should be developed to improve the safety and efficiency - best practice
should be shared.


Produced Water Disposal (Moderate)
Produced water with 20ppm oil content (within allowable limits) can create a sheen
when discharged from an FPSO in still water. This is in conflict with industry aspirations
of minimum environmental impact.

Work is required into the emulsification of produced oil in seawater and reasons for the
formation of a free oil sheen. Studies should indicate an appropriate mitigation and
provide guidelines on when it's use should be necessary.


Sea Chests (Moderate)
Marine growth in sea chests is a problem on all FPSO’s. It is an ideal location for marine
growth and is difficult to clean. The ability to blank off the sea chests is also required in
the event of a leaking main seawater valve. Fitting blanking plates is also time
consuming and weather sensitive. In addition the safety risks of relying on a single
blanking plate may be considered unacceptable.

The need for sea chests (normally used in vessels underway) needs to be reconsidered.
Options that reduce opportunities for marine growth and allow blanking off in the event
of valve failure are required. Consideration should also be given to submersible pumps
in a caisson - (see above).


Power Generation (Moderate)
Warstilla diesels are required to run on diesel and gas. This has proven difficult in
practice. Main concerns have been safety related, whereby HP gas has to be routed into
an engine room where the risk of fire is already high. HP fuel gas compressor design
and reliability has also been a concern.

A solution is required to fundamentally improve the safety and reliability aspects of
running diesel engines on Natural gas.


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                                  OLF FPSO Project 2002


Turret

Swivels/Tie-backs (Major)
Increasingly opportunities to tie back new fields are being considered. This allows
volumes to be maintained while the primary field reaches tail end production. There are
a number of constraints including available riser slots, swivel capacity or paths, ability to
produce separate streams, metering and control upgrades.

Typically the swivel and turret are the most challenging areas for upgrade. A low cost
method is required to upgrade swivel capacity and pull in new risers with minimum shut
down time.


Swivels (Moderate)
While swivel repairs have not yet been required, a methodology to simplify repair and
seal replacement is required. At present a repair to a key seal may take up to 5 days.


Project Management

Design Input from Operations (Major)
It is agreed that Operations input a key to good design, however on 4/5 FPSO’s staff
consider operations input inadequate. Reasons are lack of an operating organisation,
lack of operations experience, concern at capex over-runs, lack of data for operations to
justify more expenditure and information provided too late.

The challenge for operations staff is to be able to provide a reasoned justification for
Capex vs. Opex trade offs based on past operating experience. Data must be presented
in a quantitative way and early enough to support investment decisions in appropriate
design and quality requirements.


Operations & Support

In Situ Repairs and Modifications (Critical)
FPSO’s are placed on location for the duration of field life typically 7-20 years. This
means that all-major repairs, inspections and maintenance must be carried out in situ.
Marine standards and codes assume periodic visits to port and occasional dry-docking.

The challenge is to revise all aspects of marine standards including quality control,
material specifications, coatings, fatigue analysis, subcontractor management, and
mechanical handling to take account of the need for minimum maintenance and in field
repair.




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                                 OLF FPSO Project 2002


Process (Major)
Failure of separator or coalescer internals due to sloshing is a common problem of
FPSO’s (reported by 3 out of 5). Reason is fatigue of internals due to poor support. The
cost of such failures is very high - shut down and repair costs.

It appears that suppliers have not adequately understood loads associated with
separators on FPSO’s. Work is required to define fluid loading and build an industry
specification for moving separation equipment to eliminate the problem.

Role of Vendors / OEM (Major)
Primary equipment vendors have little involvement in the operation of equipment. This
has two drawbacks, the Operator has difficulty accessing adequate specialists to assist in
problem resolution and the supplier has little opportunity to learn for operational
experience.

The challenge is to secure a commitment for technical support or a minimum
performance level when the equipment is competitively bid and purchased.            This
requires expectations to be set up front by the Operations team. If the supplier refuses
to offer a performance level, another supplier should be preferred.


Solids Disposal (Moderate)
Disposal of high solids content fluids is always a problem on an FPSO. The ability to
clean up a new or treated well via the FPSO would add value over field life. In the event
of paint stripping or tank cleaning these solids could also be routed to the solids tank.

Consideration should be given to a third slops tank specifically designed for high solids
fluids and solids drop out. The tank would have easy cleanable surfaces with jetting
lines and solids/slurry handling pumps.


Documentation (Moderate)
Every Operator has complained of inadequate documentation. Primary problems have
been late documentation from suppliers, missing data from subcontractors (particularly
marine suppliers), inability to get paperless systems up and running even one year after
start-up, missing as built drawing and loop diagrams, incompatible tags and poor links
to maintenance databases.

The problem appears to arise from inadequate specification of documentation
requirements at order placement. It is also a low priority for suppliers after the
equipment is delivered and paid for. Follow up is often inadequate. Different
specifications from Operators are also a problem. This is an opportunity for a joint
industry initiative, perhaps building further on Norsok standards.




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                                 OLF FPSO Project 2002


Standby Vessels (Moderate)
All FPSO’s are using SBV’s in different ways, including storage, firefighting, ROV
inspections, tug support during offloading and one FPSO is sharing with a Platform
60kms away - and holds a large daughter craft on board.

The challenge is to share best practices and agree a common role for the vessel and it's
specifications so that every FPSO can get best value from the vessel and achieve
appropriate standby cover at most economical price.


Codes/Classification

Approvals & Safety Verification (Major)
While all FPSO’s were built to Class, 4 out of 5 have now dropped Classification. Their
view is that there is little to be gained from remaining within the "marine" inspection
and approval regime offered by leading classification societies. NPD do not require
ongoing classification.

There is potential value in classification, but there is a view that the societies have not
kept up with the demanding design, build and manning requirements of FPSO’s. The
challenge is for Classification Societies and Operators to tighten FPSO’s class
specifications so they become fully effective both for Operators, builders and regulators,
in both build and operation phases.




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7.         Norwegian FPSO Successes

Evidence suggests that what goes wrong is more likely to be remembered than what
goes right. In both the Norwegian and the UK research exercises the interviewees were
more forthcoming with information about problems and challenges faced, solutions
identified, remedial actions undertaken and lessons learned. People were often reticent
or unsure about classifying something as a success or a potential best practice. This is
often in part because of the difficulty people have in comparing their experiences with
those of others and then coming to an informed conclusion as to what is a good or bad
practice or performance relative to a norm. It is hoped that these type of knowledge
exchange initiatives will in future assist FPSO specialists to report both positive and
negative experiences relative to established best practice.

Reported Norwegian success stories are highlighted in Table 3 of the Appendix. These
include:

Hull & Marine

Inert Gas Systems (Major)
One FPSO was designed with Hydrocarbon blanketing to replace inert gas. Following
successful proof of concept, this is now being extended to others. As well as eliminating
venting or flaring, it reduces use/maintenance of the inert gas generator.

Motion Assumptions (Major)
Motion has not been a significant problem for production regularity in Norwegian
FPSO’s. The key has been selection of effective level control instrumentation.
Longitudinal separator placement has been successful. One FPSO was able to maintain
full production in 12m significant wave heights. Motion effects on people has been
reported as a minor issue, particularly for people coming from fixed platforms.

Mooring Integrity (Major)
Mooring integrity appears to have been better resolved in Norway compared with their
UK counterparts where a recent Noble Denton study suggested this was a major
problem area.

Material Selection (Moderate)
Material selection strategies that started early have had good results. Another FPSO
reported that the hull is mainly carbon steel, several exotics- titanium seawater and GRP
pipe have both been a success.

Turret

Swivels (Major)
Overall the performance of swivels on the 3 FPSO’s has been good. There have been no
significant leaks; the only major problem was two failures and an explosion in the oil



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filled 11KV-power transfer swivel.   This was due to water entering the insulation oil
medium.

Project Management

Project Learning/input (Moderate)
There is evidence to suggest that a number of Norwegian FPSO projects benefited
significantly from knowledge sharing of lessons learned from other projects in
development at the same time. Operator’s staff and nominees working in the yards
during construction and commissioning phases appear to have been adept at seeking
out and implementing good practices from other operators and the DNV.

Operations & Support

Uptime Performance (Critical)
Where reported uptime performances have been excellent.

Compression Start-up (Major)
One Norwegian FPSO had gas compression up and running 7 days after first oil. This
was claimed as an industry record and was attributed to comprehensive commissioning
work and operator training.

Shuttle tanker/offloading (Major)
FPSO/Shuttle tanker offloading has been very successful. Only two minor incidents
occurred out of approx. 1000 offloadings - one contact when some light structural
damage was sustained and one rope round the thruster. Incidents of missed loadings
due to weather have also been very few.


Manning & Safety

Crew Organisation
Decision to have good professional marine competency onboard has been beneficial.
OIM is mariner, plus additional marine superintendents. Onshore management has
strong confidence in offshore team to use their judgement to maintain stability and
routinely undertake vessel related activities e.g. tank cleaning.


Safety Performance
All operators reported good FPSO safety performances, backed up by proactive safety
cultures to enhance and extend good safety practices within project contractors and
shipyards.




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8.         UK FPSO Lessons Learned

In 2001 the Offshore Management Centre at the Robert Gordon University in Aberdeen
completed a similar knowledge sharing research exercise on behalf of the FPSO
committee of the United Kingdom Offshore Operators Association (UKOOA). Part of the
research involved the collection of lessons learned from the first 12-18 months operation
of FPSO’s on the UKCS. Like the OLF project a number of specialists representing ten
FPSO’s were interviewed and their views collated. Whereas the emphasis and
information reporting in the UK study were slightly different, it is worthwhile trying to
align some of the experiences and lessons learned from the two areas.

     The main conclusions from the UK work were as follows:

•    It appears that the majority of problems arose because of the way the projects were
     structured and managed.

•    Decision and actions taken in the design and construction phase are the most
     probable causes of problems in commissioning and early operation.

•    Problems have also been caused by lack of communication between isolated groups
     involved in design.

•    The misapplication of functional specifications has led to operational problems.

•    It appears that the responsibility for QA/QC was not clear and this has led to
     problems with equipment delivered which was not fit for purpose.

•    A major cause of early operational problems was that FPSO’s were sailed to their
     location before their construction was complete and before their systems had been
     fully tested.

•    Knowledge of lessons learned does not seem to be shared readily across the UK
     FPSO industry. A change of attitude will probably be needed before the situation will
     improve.

A synthesis of the most widely reported issues/problems relating to UKCS FPSO’s is
shown in Table 4. Also shown in Table 5 are a checklist derived from information
collected during interviews with UK operators of FPSO’s in September and October 2000.
The checklist was produced to assist the avoidance of decisions and actions, which could
lead to problems during start-up and operations. Where appropriate, hyperlinks have
been created between the UK suggestions in Table 5 and related Norwegian experiences
documented in Table 2.

A significant majority of FPSO related problems are attributable to the design phase.
There is clear evidence from both the Norwegian and UKCS research of the existence of
communication problems in the design process and that input from personnel with
operational experience has been undervalued at this stage. Emphasis on initial capital
cost control and fast-tracking has lead to poor design decisions negatively impacting for
years to come on the operational efficiency of a number of FPSO’s and their workforce.


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It is essential that lessons learned feedback from knowledge sharing initiatives such as
this are channelled back to the FPSO design companies and their staff. It is equally
important the customer maintains an adequate degree of internal competency and
understanding to ensure the operational design specification is fully fit for purpose.

There have been a number of problematic issues common to both Norwegian and UK
FPSO’s. These have included:

Crane design and mechanical handling issues. Many FPSO’s have been designed with
inefficient cranes, poor crane coverage and inadequate lay-down areas, bumper bars
and mechanical handling capabilities. This appears to be due to lack of familiarity of
operational needs by designers.

Both Norwegian and UKCS FPSO’s have struggled with accommodation POB restrictions.
Prioritisation of construction and engineering work presents real challenges because of
limited POB flexibility.

There are examples from both the Norwegian and UK project experiences that too much
faith can be placed in the knowledge of the supplier. This can be a significant problem if
functional specifications are not clarified down the supply chain. There are many
examples of suppliers and even constructors not appreciating the distinctive nature of
FPSO operations i.e. assuming that the vessel can be taken off station and brought into
port if there are any problems. Designers have not adequately faced up to the
challenges of simplifying failed equipment removal mechanisms for FPSO’s. The change
out of power generation systems and thrusters has and will continue to represent a
major operational challenge.

Both Norwegian and UK FPSO’s have had experiences of poor quality painting and
coatings during the construction phase. When not properly addressed at the time this
factor has the potential to create significant POB scheduling problems at a later stage.

Some problems attributable to the effects of motion have been reported from both
Norwegian and UK FPSO’s. These appear to be mainly where there has been insufficient
attention to the effects of sloshing inside tanks and damage to separator internals as a
consequence of fatigue.

Vessel orientation and location of venting problems resulting in exhausts and other
emissions being blown over vessels have been experienced in both the UK and Norway.




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