Student Ingrid Almås Berg
Design for Reliability –Applied to development of subsea process systems
AppendicesTrondheim, June 14th, 2010
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Appendices There are 6 appendices to this report numbered from A to F. Except for the preliminary report the appendices are confidential and therefore left out of the main report. The appendices are meant to be read together with the main report and a description of how this should be done is given in chapter 1.3.
The appendices are the following:
A) System description of the Midgard Subsea Compression System B) Project execution model for Technical Qualification in Aker Solutions C) Aker Solutions methodology for reliability D) Project Execution Model (PEM) for Aker Solutions E) Equipment Reliability Management Programme (ERMP) for the Midgard SCS F) Preliminary report
Appendix A – System description Midgard SCS This Appendix describes the Midgard Subsea Compression System. The Åsgard field is situated on the Halten Bank in the Norwegian Sea about 200 kilometres from the Mid-Norway shoreline. The Åsgard B platform receives gas production from the Midgard and Mikkel reservoirs. Due to a decline in natural pressure from the reservoirs, additional pressure support will be required to maintain a stable production flow from the Midgard and Mikkel reservoirs from 2014 and onwards. To meet these needs Aker Solutions has developed a Subsea Compression System.
Subsea compression is considered to be a more environmentally acceptable concept compared to a platform based compression solution. Subsea compression is designed for close to zero direct emission of substances to air, and the amount of raw materials required for construction will be significantly lower than for a platform. In addition, the subsea alternative contributes to a significantly lower risk for personnel as it is unmanned.
A subsea compression station will also be located closer to the well, thus requiring a lower inlet pressure and it is a less costly alternative than a platform solution.
Figure A - 1: Åagard field location (european-interaction.com) and Åsgard field development sketch (regjeringen.no)
The Subsea Compression System (SCS) comprises a Subsea Compression Station (SCSt) with two compression trains and a Subsea Compression Manifold Station (SCMS).
Power and Control is supplied to the SCS through 2 combined Power and Control Umbilicals. The umbilicals are terminated in a Transformer and Umbilical Termination Module.
The SCS is illustrated in figure A - 2
Compression Train installed on alignment frame
The Subsea Compression System can be broken down into three sub-systems:
- Process system - Control system - HV power system
Each sub-system is described in detail in the following sub-chapters.
SCMS
SCSt
Figure A - 2: Subsea Compression Station and Subsea Control Module System
A.1. Process system The process system consists of the following:
1. A manifold with station by-pass valve and isolation valves. 2. Two compression trains, each consisting of the following main process modules:
- Interface Spool Module - Combined Inlet/Anti-Surge Cooler Module - Scrubber Module - Condensate Pump Module - Compressor Module - Discharge Cooler Module - Stand-alone Subsea Control Module
Each compression train is installed on an alignment frame that allows for installation of one complete train, as shown in figure A- 2:
Compressor Train
Transformer and Umbilical Termination
Module
Train Base Frame
Figure A - 3: Compression Train installed on alignment frame
The main modules will in the following tables be presented with a short description and a figure.
Table A - 1: Compressor train modules
Name Figure Description
Manifold
The name is old English and refers to the "folding together of many inputs and outputs” (wikipedia). The manifold for Midgard is a quite simple manifold that directs the flow from the reservoirs to and from the Subsea Compression Station. The manifold consists of piping and valves, both ROV and electrically operated.
Template Structure
The SCSt structure gives the support and protection for the Compressor trains and the UPS and UTA modules. It is designed in accordance with the soil conditions, pressure ratings and temperatures of the field.
Compression Train Base Frame
The compressor train base/alignment frame is the foundation for all the process modules.
It is designed to be installed/retrieved to the SCSt with all process modules in place, and with all process and control connections made up and tested prior to loadout.
Interface Spool Module
The Interface Spool Module consists of piping and hubs and is meant to distribute the tie-ins between the Subsea Compressor Manifold System (SCMS) and the modules on the Compressor Train base frame. It shall also serve as a foundation for the Inlet cooler.
Combined Inlet/ Anti-Surge Cooler Module
The function of the combined inlet and anti-surge cooler is to cool the inlet gas temperature. The anti-surge flow from the compressor will have a high temperature due to heating from the compression. Also the inlet temperature from the wells may have a high temperature during certain production phases. The inlet cooler module consists of long, thin pipelines exposing it to the temperature of the seawater surrounding the pipe. As a result of how the pipe is constructed, the element will spread out and thus the temperature is lowered.
Anti-surge is necessary when the flow does not match the current operating point of the compressor (emersonprocess.com). Especially when the amount of gas coming in to the compressor is higher than it can handle.
Scrubber module
A scrubber is a separator. In this system the scrubber's function is to separate gas and liquid going into the compressor. This will ensure that only gas enters the compressor, as it can only handle limited amounts of liquid.
Condensate Pump Module
The Condensate pump module includes a pump and motor unit based on Aker Solutions’ own LiquidBooster™ technology. The purpose of the pump is to drain the condensate water from the separator and to further boost the liquid phase before it is re-injected into the gas phase.
Compressor module
A compressor reduces the volume of a gas or liquid in order to increase the pressure. In this system the compressor is a gas compressor. The increased pressure is meant to be added to the current pressure of the Midgard and Mikkel reservoirs.
Discharge cooler module
Like the inlet cooler module, this is meant to cool the flow coming through the pipes from the compressor. The flow from the discharge cooler will be reconnected to the flow from the pump module and then discharged into the main production flowlines.
Figure A-4 shows how the modules in the compressor train are connected and how the flow goes through it.
LC
SC
M
M
PT
PT TT
FT
ASC
Note 1
Note 2
FC
HOLD 7
HOLD 1: Actual inlet / anti surge cooler arrangementHOLD 2: DeletedHOLD 3: Sand removal arrangementHOLD 4: Barrier fluid (MEG/Oil) not decidedHOLD 5: Demisting internalsHOLD 6: Requirement of hot gas BYPASS based K-Lab trip test resultsHOLD 7: Exact design of compressor drainage
NOTE 1: GVF controlNOTE 2: Inlet device of type spinlet or evenflowNOTE 3: Maintain straight length upstreamNOTE 4:
SCMS
SCMS
Hold 3
SCSCRUBBER
INLET/ANTI-SURGE COOLER
CONDENSATE PUMP
COMPRESSOR
OUTLET COOLER
PC
Barrier fluid from PLIM
Motorcooler
Hold 4
PVR
SY
HSC
M
Hold 5
HGB
HOLD 6
ROHLL
NLL
LLL
M
min
Hold 1
RC
M
FT
A.2. Control and HV Power system HV Power and Control is supplied to the SCS through 2 combined Power and Control Umbilicals. The umbilicals are terminated in a Transformer and Umbilical Termination Module. The Combined Transformer and Umbilical Termination module holds the main subsea electrical equipment and provides an interface towards the control equipment. The HV Power cables in the umbilicals supplies power to the electric motors for the Compressor and the Pump, as well as power to the UPS.
The Control and HV Power system mainly consists of the following:
- Topside controllers - Topside Circuit Breaker - Topside Variable Speed Drives for HV Power - Combined Power and Control Umbilical - Subsea Transformers - UPS (Uninterruptible Power Supply) - Subsea Communications network - Subsea control modules with controllers and routers - Interconnections - Subsea HV connection system for retrievable compressor and pump unit.
Name Figure Description
Topside controllers The SCSt needs input and follow-up topside in order to function as required, especially when alterations and shut-downs are needed. The topside controllers receive the information topside and pass it on to or from the subsea systems.
Input circuit breaker The circuit breaker is meant to protect the electrical circuit in case of a fault, e.g. overload. It detects failures and breaks off the electrical flow.
Variable Speed Drive -Frequency converter
A frequency converter controls the alternating current of the electrical power supplied to a system and converts the incoming alternating current frequency to the correct frequency for the compressor and pump (wikipedia.com).
Combined Control and HV power umbilical
An umbilical provides the power and communication to and from topside to the SCS. The umbilical contains HV power cables for power supply to the electric motors and to the UPS, fibre optic cables for communication and a barrier fluid distribution line for the pump. Each compression train is connected to a dedicated umbilical.
Umbilical terminations Umbilical termination and Subsea transformer module
This is where the umbilical going between the platform/ship and the seabed is connected. The termination usually includes armours, tubes and other tensile-strength elements.. At the termination the power cables are connected to the respective transformers while the fibre optic cables are distributed to the subsea control modules (SCM).
Subsea Step-down Transformer
Step-down transformer:
Step-down transformers are used to decrease the voltage current in to or out from a module. The cables between topside and subsea installations create a resistance which alters the voltage. Due to this the transformers are introduced in order to ensure that the necessary and correct voltage for use.
Three step-down transformers are included in the Subsea Transformer Module; a step-down transformer for the HV power supply to the compressor, a step-down transformer for the HV power supply to the pump and a step-down transformer for the UPS supply.
UPS
The UPS system provides auxiliary power to the compressor subsea control equipment in case of loss of the primary power supply. It comprises energy storage means and a power conversion system to charge it with. The UPS also has a control system and a cooling system
Each UPS shall be able to provide power to both compressor trains at the same time when the ordinary power supply is lost
Subsea control modules.
The typical SCM recieves communication signals and electrical power supplies from the topside control equipment. These modules then use the signals to control the subsea system (www.freepatentsonline.com).
Active Magnetic Bearing Control Module
The Active Magnetic Bearing Control Module controls the magnetic bearing that levitate the compressor. The motor-compressor has three radial bearings and one axial, which requires a 7-axes AMB control system. The ABM assemblies also contain emergency run-down bearings of ball bearing type to safely run down the motor-compressor in case of magnetic bearing failure.
Subsea HV connection system
This is where the HV power umbilicals or cables are connected and the electrical current sent on to transformer systems subsea, and from there on to the electric motors.
Appendix B – Aker Solutions Technical Qualification
System requirement
definitionGap Analysis
Develop Technical Qualification plan
(TQP)
GO/ NO-GO
meetingR&D Project set-up
NO-GO
GO
Evaluate external technical
alternativesProcure external
solution
M1A
1A - Opportunity appraisal
ENGINEERING
Basis of designS2
ENGINEERING
SoWS5
GAP Report Internal wishesMarket needAker Solutions
technology status
Client spec
ENGINEERING
GAP ReportS5
Tender need SoW Basis of design Lesson learned
ENGINEERING
Risk register
ENGINEERING
Schedule
ENGINEERING
CTR & Budget
ENGINEERING
MPP
ENGINEERING
WBS
ENGINEERING
Top level SAP structure
ENGINEERING
TQP
ENGINEERING
Project organisation
chart
Project Execution Model – Technical Qualification Page 1 of 8Title
Eng(M1B)
MILESTONE REVIEW
PROCURMENT
PO
M1A M1B
1B – Concept development & selection
ENGINEERING
Concept development &
selection Kick off
Concept Development
Concept design review S02
Concept screening/ selection
TQPUpdate
Design BasisConcept design
review Client feedbackConcept design
review S02
MANAGEMENT
Budget
MANAGEMENT
MPP
MANAGEMENT
Risk mitigation plan
MANAGEMENT
Risk register
MANAGEMENT
Project schedule
ENGINEERING
Concept design review S05
Fallback solutionsPrimary concept
ENGINEERING
Fallback solutions
ENGINEERING
Primary concept
ENGINEERING
Component test requirement evaluation
ENGINEERING
IP search
MANAGEMENT
CTR
Eng(M1A)
MILESTONE REVIEW
Project Execution Model – Technical Qualification Page 2 of 8Title
2A - Detail Engineering & Procurment of LLI’s
M1B M2A
MILESTONE REVIEW
PROJECT KICK OFF
DETAIL PRODUCT DEVELOPMENT
Eng.(M2A)
Supply Chain(M2A)
PROCUREMENT OF CRITICAL LONG LEAD ITEMS &
SERVICES
TQP
FMECA review.
S2Pre FEA
S2SAP BOM
S2
Detail design fileS2
MDL S2
I/F DataS5
Purch. Orders LLI
ITP LLI
Concept design file
Patent application
S5
REVIEW MANUFACTURING
AND A&T CAPABILITY AND
REQUIRED CAPACITY
PMS/OPR
Basis of Design
Make/buy strategy
MANAGEMENT
LLI
ENGINEERINGENGINEERING ENGINEERING
ENGINEERINGENGINEERING ENGINEERINGENGINEERING
PROCUREMENT AND QS FOLLOW
UP
Alloc. Stock items
Supplier ITP’s EPMS SMDL’sEng. Docs.
Project Shedule
LLI - Drawings and material
S5
ENGINEERING
3D layout froozen
ENGINEERING
Update Project
Schedule
MANAGMENT
Scope of Supply
S3
ENGINEERING
Quotation DRW’s
S2
ENGINEERING
Quotation DRW’s
Quotation DRW’s
Project Schedule
Project Schedule
TQP
DETAIL ENGINEERING FOR LONG LEAD ITEMS
Updated basis of design
ENGINEERING
BOM skeleton
A&T
ENGINEERING
Fallback solutions
MPP
PMS/OPR
PROCURMENT PROCURMENT PROCURMENT
QS Plan
PROCURMENT
Insp. Rel. Note
PROCURMENT
Project team
MANAGEMENT
Meeting Minutes
MANAGEMENT
Secure Manuf Slot
PROCURMENT
Manufacturig design review
A&T design review
DETAIL ENGINEERING FOR MANUFACTURING
DETAIL ENGINEERING FOR
ASSEMBLY AND TEST EQUIPMENT
Detail design fileS2
ENGINEERING
Detail design fileS2
ENGINEERING
BOM skeleton
ENGINEERING
Detail design fileS3
ENGINEERING
E-05
-09
E-05
-10VERIFICATION OF
QUALIFICATION PROGRAM
TQPDesign Verif.
TQP Status
TQP Schedl. verif.
ENGINEERING ENGINEERING
Component testing
Procurment strategy
PROCURMENT
Eng(M1B)
Project Execution Model – Technical Qualification Page 3 of 8Title
M2B
2B - Final Engineering for procurment
MILESTONE REVIEW
M2A
Supply Chain(M2A)
Eng(M2A)
Supply Chain(M2B)
MTRL & BOM A&T
S5
FINAL ENGINEERING FOR
PROCURMENT Eng.
(M2B)E-05
-09
E-05
-10VERIFICATION OF
QUALIFICATION PROGRAM
TQPDesign Verif.
TQP Status
TQP Schedl. verif.
SoSS5
FMECA REPORT
S5
FINAL FEAS1
MTRLS & BOM S5
PROCUREMENT AND QS FOLLOW
UP
EPMS Eng. docs.SMDL’s
Doc approv’lS5
Inspec. notes
S2QS Plan
ENGINEERING
Supplier ITP’s
Closed PO’s
ENGINEERING
FMECA ResultsPre FEA
MDL I/F DataProject Schedule
Eng. Report
ENGINEERING
Updated A&T
drawings
MDL S2
ENGINEERING
Updated Project
Schedule
Manufacturig design review
A&T design review
FINAL ENGINEERING FOR MANUFACTURING
FINAL ENGINEERING FOR
ASSEMBLY AND TEST EQUIPMENT
Draft weld / mach drws
Final design fileS2
Finale design file
S2
ENGINEERING
Finale design file
Weld / mach drawings
S2
Draft Assy drawings
Draft test setup drws
Updated manufacturing
drawings
A&T equi drwsS2
Test setup drwsS2
ENGINEERING
Assy drwsS2
ENGINEERING
Drawing review
BOM Skeleton
Updated BOM
A&T BOM skeleton
A&T BOMS2
Updated BOM
Final design fileS2
ENGINEERINGENGINEERING ENGINEERING ENGINEERING ENGINEERING ENGINEERINGENGINEERING ENGINEERING ENGINEERING ENGINEERING ENGINEERING ENGINEERING ENGINEERING
Project Execution Model – Technical Qualification Page 4 of 8Title
M2C
3A - Sub-contracting and Manufacturing
MILESTONE REVIEW
M2B
Eng.(M2B)
Supply Chain(M2B)
Eng(M3C)
Supply Chain(M3C)
TQPDesign Verif.
VERIFICATION OF QUALIFICATION
PROGRAM
TQP Status
TQP Schedl.verif.
PROCUREMENT AND QS FOLLOW
UP
Supplier ITP’s SMDL’sEPMS
Doc approv’lS5
Insp.Rel.
NoteQS Plan
Eng. Docs.
Closed PO’s
ENGINEERINGENGINEERING
DETAILEDMANUFACTURE
PLANNINGMANUFACTURE
ACTIVITIES
Router
Shop flSched.
Prod order release
S5
Manuf Spec TraceabSheets
ITP ManufProc.
Comlp. PartsManuf.
DocS5
MANUFACTURING PREPARATION
BOM
Assy Proc.
Manuf. BOMManuf. Spec.
ITPS5 Pick List f/
manf
Manuf. Spec.
Manuf. Proce.Manuf. BOM
Router ITP Manuf. drawings
Trace. SheetsRough Cut
MANUF. MANUF.MANUF.ENGINEERING ENGINEERINGMANUF. MCMANUF.MANUF.
A&T Tool list
ENGINEERING FOLLOW-UP
OPR/PMS
PROCUREMENT OF BOM ITEMS &
SERVICES
Purch. Orders
ITP
OPR/PMS
Purch. Orders LLI
Released BOM
Released BOM A&T
Equip
RFQ Make/buy strategy
Drawings
Manuf.(M3C)
VQN/PQN
Project Execution Model – Technical Qualification Page 5 of 8Title
M3B
3B - Pre-fabrication & Engineering
MILESTONE REVIEW
M3A
Eng.(M3A)
Manuf.(M3A)
SupplyChain(M3A)
Eng.(M3B)
Manuf.(M3B)
SupplyChain(M3B)
DETAILED ASSEMBLY & TEST
PLANNING
BOM’s
SAPShort
List S5
Prod.Order
S5Picking list f/
Assy
Assy Proc. Trace sheets
INITIALMC ACTIVITIES
PROCUREMENT AND QS FOLLOW UP
GOODS RECEIVING FROM SUPPLIERS AND OTHER WP’S
SMDL’sSupplier ITP’s
Doc. Approv’l
S5QS Plan
EPMSIncome Matr’s
S5
Matr. Doc.S5
Vendor NCR’s
Test & Assy Router
MCCR Sheets
Man. BOM
ITP
PVT
MRBS1
LCI Req. Mat. Doc.
MANUF.ENGINEERINGENGINEERINGMANUF.
MCMANUF.ENGINEERING
MANUF.MANUF. MRP PROCUR.
MANUF.
LCI PlanBOM
MCCR Sheets
S5
MANUF.
Eng. Docs.
Closed PO’sInsp. Rel.Note
Appr. Matr’sS5
E-05
-16
3rd party notification
3RD PARTY.
Engineering for A&T - Procedures
and documentation
VERIFICATION OF QUALIFICATION
PROGRAM
TQP Status
Complete Engineering
MDL
Assembly Procedure
S5
PVT Procedure
S5
SAFOPS5
Assembly S5
ENGINEERINGTest
SchematicS5
ENGINEERINGTest
Stackup drwS5
ENGINEERING
A&T design review
FATS5
ENGINEERING
Finale design file
S3
FINAL FEA Finale design file
ENGINEERING ENGINEERING ENGINEERING ENGINEERING ENGINEERING ENGINEERING ENGINEERING ENGINEERING
TQPDesign Verif.
TQP Schedl.verif.
ENGINEERINGENGINEERING
GA DrwS5
Product data sheet
S5
Finale design file
S5
FEA REPORT
S5
Project Execution Model – Technical Qualification Page 6 of 8Title
M3C
3C - Assembly & test
MILESTONE REVIEW
M3B
Eng.(M3B)
SupplyChain(M3B)
Eng.(M3C)
SC(M3C)
PROCUREMENT CLOSE OUT
Vendor Doc
ASSEMBLYManuf.(M3B)
FAT/PVT
(M3C)
PRODUCT VERIFICATION
TESTINGQ CONTROL(REVISION)
PVT completed
Test doc.S5
Manuf Spec
A&T Manf. DocS5
ITP
ManufProc.
PO ClsReport
Updated MRB
Manuf.Spec.Assy
Manf. Doc.
Trace. Sheets
Assembly Proc.
Trace. sheetsITP PVT
Q CONTROL(VERIFICATION)
MRBS5
Sub-Assy Test doc.
Manuf.Proc
MCMANUF.MCMC MANUF.
BOM’s Drawings
TraceabSheets
S5
MANUF.
E-05
-60
E-05
-45
Engineering Follow-up
ENGINEERING
Test reportS5
FAT Procedure
Project Execution Model – Technical Qualification Page 7 of 8Title
M4A
4A - Close-out and Handover
MILESTONE REVIEW
M3C
Eng.(M3C)
Eng.(M4A)
Project Execution Model – Technical Qualification Page 8 of 8Title
R&D project closure Handover meeting
ENGINEERING
IP search documented
ENGINEERINGENGINEERING
Prepare sales presentation
ENGINEERING
Product cost
ENGINEERING
Document released BOM
ENGINEERING
Lesson learned
ENGINEERING
Prepare risk evaluation
ENGINEERING
Pos and subcontract
closeout
ENGINEERINGContract close-out
report issued if required
ENGINEERING
Punch list cleared
All required documents are released in SAP
Appendix C – Methodology for the Aker Solutions Technical Qualification Each page in Aker Solutions’ technical qualification model is between two milestones and marked by a number and a letter from 1A to 4A. These numbers can be found in the following table where they are listed according to the phases they are thought to correspond with. The technical qualification model finishes with handover and phases 6 to 8 are therefore less relevant for Aker Solutions, as any actions after handover mainly lies with the client. The factors contributing to unreliability, as discussed in chapter 7, are used as a basis together with the general methodology presented in chapter 8.
Phase Aker Solutions’ project execution model
1 1A + 1B
2 2A
3 2B
4 3A + 3B
5 3C + 4A
6-8 No direct comparison possible
As Aker Solutions whish to develop more shelfware products in the future, the general methodology might become even more useful to them. The question will then be whether to develop a new methodology, including the final phases and a more extensive phase 5. What is certain is that phase 6 from the general methodology would become more interesting to the development projects.
Phase 1
Opening for a new product
GAP analysis
System requirement
definition
Develop Technical
Quakification plan (TQP)
GO/NO-GO meeting
Recommence project?
Yes
Terminate project
No
Concept Development &
selection Kick off
Yes
Project tasks Project reliability tasks
QFD
Reliablity, availabllity and maintainability reqiurements
HAZID, SWIFT, Early FMEA
Create reliability programme
Desired reliability
Reliability report 1A
Evaluate external technical
alternatives
R&D Project set-up
Procure external solution
No
Concept screening /selection
TQP update
1B
1A
Reliability report 1B
Reliability programme
update
2A
Concept development
Figure 1: Phase 1 for Aker Solutions
The Subsea Power and Process department at Aker Solutions can start a development process of new technology either based on client needs, or a perceived market need. As all the projects the department participates in have very specific demands and an environment which changes from one operational area to another. The Subsea Power and Process department is still rather new on the market and their subsea process systems are thus also new solutions. Currently they do not produce much on a larger scale, but this is the wish for the future. If a product such as the Subsea Compression System (SCS) is produced on a larger scale, it still needs to be altered for each new oil or gas field. It is important that
even the larger scale products, remains highly qualified to perform the desired functions. The Midgard SCS is a good example as another SCS is in development for the Ormen Lange project.
The current project execution model for technical qualification starts in 1A with the GAP analysis on which the system requirement definition is based. As the content of the GAP analysis is not described, it is possible to suggest that a QFD is performed before or as a part of it. The technical qualification does not include any specific reliability activities in the first phase, although some may say that reliability requirements are an obvious part of the system requirements. If the client is the initiator, availability and possibly reliability requirements will be handed directly to Aker Solutions. What the team investigating the possibility of a new product then has to do, is to decide whether they want to stick with the requirements. The alternative is to settle on even stricter requirements. A good reason for this would be that it increases the competitive powers for future projects, as well as the current.
When the requirements have been specified, a technical qualification plan is developed. A reliability programme should then be based on this, or developed concurrently with it. As the technical qualification follows a preset project execution model, a reliability programme would do so as well. It should consist of the methods most suitable for the specific system and the dates scheduling the analyses.
Phase 1 also includes part 1B of the technical qualification. This is where the concept is developed and chosen, before the project is started on a larger scale. In order to choose the best idea, economy, time, feasibility and reliability must be considered. The demands for these aspects were specified in part 1A and each concept will be reviewed according to them. In order to see whether the reliability of the concept can answer to the requirements, early hazard analyses should be performed. HAZID and SWIFT are suitable for such a purpose, either alone or together.
The main functions of the system, as well as some of the sub-systems will to an extent be decided on before phase 1 ends. As soon as hazards and possible failures are discovered, an FMEA is begun. If it is possible to rank the criticality of a failure, the FMEA is extended to an FMECA. More reliability methods of both quantitative and qualitative manner ought to be implemented as the concept develops, depending on the existing knowledge about the system. An evaluation of the possibility of reaching the reliability requirements for the specific concept must be performed. This is part of the information needed to decide whether the concept is acceptable or not. If the reliability engineer has desires for improvements for the concept, this should be included.
Based on the chosen concept, the technical qualification programme is updated. When this final part of 1B is performed, an update of the reliability programme must be done simultaneously.
Phase 2
Input from reports phase 1, e.g. HAZID, SWIFT and FMEA results
Phase 2: Aker Solutions2A Detail Engineering & Procurement of LLI’s
Project tasks Project reliability tasks
Update FMEA
FTA and/or RBD
Create overview of reliabilty predictions
RAM analysis
Document reliability results
etc.
Reliability allocation
2A
Detail Product development
Detail engineering for manufacturing
Detail engineering for assembly and test equipment
Detail engineering for Long Lead
Items
Verification of qualification
program
Project kick-off
Review manufacturing and A&T capability and required capacity
Procurement of critical Long Lead Items & Services
Procurement and QS Follow up
2B
Early HAZOP
Reliability analysis for procurement where necessary
Process FMEA SWIFT/HAZID for production
Human factors analysis
Compare predictions with desired reliability and requirements
Compare predictions with desired reliability and requirements
Figure 2: Phase 2 for Aker Solutions
As the system development continues in phase 2, part 2A begins. This is where the project team is chosen in Aker Solutions. Although it is normal to leave the first phase to managers from the manufacturer and the client, it is advisable that the main project team is included earlier on. Reliability and design engineers with experience from previous projects should be among the team members in phase 1. Whether they are included as advisors or for permanent work at an early stage, their input is valuable.
As the more detailed design begins, it will be easier to implement new reliability tools. To start with, it is necessary to perform a reliability allocation. The subsea process systems are often quite complex and an allocation will thus minimise the quantity of components which need to be studied for each update. When the product development becomes more detailed it will also be useful to update the FMEA. An early HAZOP can be implemented in order to discover more possible failures and problems of different types than those found previously.
With the system architecture in place, FTAs and RBDs are performed. These are often used together with or as a part of a RAM analysis which gives an overview of the overall reliability and availability. The RAM analysis was described in chapter 6. At this stage the reliability tasks are meant to study how the components and subsystems in the system work on each other, not to find new hazards. The discovery of critical connections can help prevent one failure from affecting the whole system through the implementation of “two off” structures. In some cases, the FTA, RBD and RAM analysis can be used to see whether planned redundant structures truly are important or may be omitted.
Phase 2 is to a large extent the one where most of the information needed for reliability predictions becomes available. Any of the tools recommended for this phase can be used for predictions. These will be based on OREDA, previous projects or subcontractors, which have all been shown to include factors contributing to unreliability in chapter 7. It is thus necessary that all choices are made with great care. Depending on whether the predicted reliability matches the desired reliability, the next phase begins. It should also be noted that any concepts matching the criteria, but considered too expensive for further development must be re-evaluated.
Phase 3
Assign requirements and functions to components,
assemblies and sub-systems
Phase 3: Aker Solutions2B Final Engineering for procurement
Project tasks Project reliability tasks
Decompose for reliability
Update FMEA, FTA and RBD
HAZOP
Are requirements and functions met with?
Document reliability results
etc.
Final engineering for manufacturing
Procurement and QS follow up
Final engineering for assembly and test equipment
Final engineering for procurement
Verification of qualification
program
Input from previous phases
No
2B
3A
Yes
Figure 3: Phase 3 for Aker Solutions
There is a difference between “detail” and “final” as keywords in the project execution model. This difference is also where phase 2 is separated from phase 3. Part 2B in the model is where the final engineering takes place before any manufacturing is planned. What may be noticed throughout Aker Solution’s model is that very few tasks directly linked to reliability are mentioned. It is stated in a document concerning the model that all design, FMECAs and HAZIDs should be finalised before the sub-contracting and manufacturing begin. To perform a HAZID after the design is frozen might be unnecessary as little new will come of it. A finalisation of the FMECA can on the other hand be wrong. This tool can be used throughout the product life cycle whenever new data are retrieved and the possible failures become more evident. Instead of a finalisation, the documents should be prepared for further use, but with a statement of “before” and “after frozen design”. Any findings from before the design was frozen will thus be recognised when the failure described occur. The failures which were not previously known can be analysed, put into the FMECA, and marked as new discoveries.
Keeping the FMECA updated throughout the product life cycle will give good input for operators, maintenance activities and later projects.
As suggested in the general methodology for this phase, a last assignment of requirements and functions could be done as the design is finalised. A HAZOP is supposed to return the best answers when the input information is the largest and most detailed collection possible. This suits the detailed information in the final design. As one HAZOP has already been suggested, this could be a shorter and less expensive update. Any discoveries that were not done before this HAZOP should be analysed and alterations made if needed.
Among the analyses done before the design is frozen, is a finite elements analysis (FEA). This is not a method made for reliability, but it is able to return helpful information about how the materials in the product will respond to the operational conditions. For a reliability engineer, it could be used as supporting material when the criticality and likelihood of a failure are stated. This can be useful together with the results of the last HAZOP for the update of the FMEA, FTA and RBD. The FTA and RBD should now be performed at the lowest level possible, showing how the smallest details may affect the whole system. When the reliability is predicted at the end of this phase, it will be based on the largest retrievable amount of information possible, without a physical product. If the requirements from the previous phases are met with, the project can continue.
Phase 4
Phase 4
Project tasks Project reliability tasks
Update reliability analysis for procured items
Prepare plan for accelerated life tests and reliability growth
Document reliability results
etc.
Analyse test results
Follow-up of test-results and possibe deviations in
production
Prepare FAT
Engineering follow-up
Verification of qualification
program
Manufacturing preparation
Detailed manufacturing
planning
Manufacture activities
Procurement of BOM items
& services
Proquirement and QS
follow-up
Engineering for A&T – Procedures
and documentation
Complete engineering
Verification of qualification
program
Initial MC activities
Detailed assembly & test planning
Procurement and QS follow-up
Goods receiving from suppliers and
qother WP’s
Testing of materials
Consider procured items for testing
3A
3B
3C
Figure 4: Phase 4 for Aker Solutions
Part 3A of the project execution model is where the manufacturing takes place. As the manufacturing is planned and performed, the general methodology suggests that an analysis of the procured items is performed. The Subsea Power and Process department starts evaluating the procurement earlier, but as some items are still received during phase 4, an updated analysis should be performed. This will provide information about the necessity of testing these parts.
When a system is installed sub sea, it is important that the materials are able to withstand the environment. The SCS will see pressures and temperatures which are different on the inside than on the outside of the system. The outer element is sea water, which brings with it the possibility of corrosion. The pressure and temperature differences mean that the materials must withstand certain stresses. As phase 4 starts, plans for testing of materials, components and sub-systems should be established. Although the SCS is a custom-built system, there is no reason not to perform tests which do not pose problems where time, resources and costs are concerned. Some items may be tested to failure without large expenditure, while other items barely can be touched. This must be taken into account when the reliability is predicted based on the new results.
Part 3B is where the detailed assembly and testing is planned. This could also mean that the basic manufacturing is partly finished, and that early testing of the smaller components is possible. Any information obtained either through manufacturing or testing should be analysed. If there are deviations in the process from the original manufacturing plan, the reliability engineer ought to study whether these affect the reliability or not.
As phase 4 ends, the handover comes closer. In the technology qualification, the FAT is found between 3C and 4A. Although the planning for this may start in phase 5, it is perhaps useful to do it when the results of the tests in phase 4 are obtained. These can be great indicators to what the test personnel must look out for during the FAT.
Phase 5
FAT
Phase 5
Project tasks Project reliability tasks
Analysis of results
Estimate overall reliability
Prepare FRACAS
Prepare for hand-over
Hand-over meeting
Document reliability results and prepare for
hand-over
Engineering follow-up
Assembly
Q Control
Product verification
testing
Q Control (verification)
Procurement close out
R&D project closure
3C
4A
End Project execution model for technical qualification
Figure 5: Phase 5 for Aker Solutions
Phase 5 for Aker Solutions is based on the thought that the systems are custom-built and rarely produced in more than one exemplary. It is thus thought that phase 5 is concerned with the overall assembly and testing of the system, the FAT. Failures or problems with the system may occur due to the assembly process in itself. This implies that problems arise due to components and/or sub-systems not working together as supposed to. Such problems can be discovered during the assembly or in the verification testing and FAT. Here a root cause analysis would be necessary. Based on the results from the tests, an overall reliability should be estimated one final time.
All analyses and test results should now be used as a basis in a reporting system between Aker Solutions and the client. A possible tool is FRACAS where all the information obtained during the operational life is reported. Documents established for reporting can also be useful to keep risk and maintainability documents “alive” throughout the operation of the system. “Living documents” are a demand in the British petroleum industry and could become of larger interest on the Norwegian continental shelf.
Before handover in part 4A, all reports and lessons learned must be noted and completed. As the Subsea Power and Process department’s purpose is to develop and design offshore equipment, any information from previous projects can be useful. All lessons learned can therefore become key to a good performance in future projects.
It is also common to hand over some of the documents to the client. Especially documents concerning possible hazards and failure mechanisms are of importance. The reliability engineer should therefore carefully gather all the necessary information, including the updated FMEA. If Aker Solutions is supposed to be the operator, the documents should be handed over to the department responsible during the system’s operational life.
Phase 6 The project execution model for technical qualification ends with handover, and does not include production of standard products after factory acceptance testing (FAT). This means that phases 6, 7 and 8 are not included with any specific project tasks. All products produced with basis in the Subsea Power and Process department must be highly reliable. It is therefore reasonable to suggest that all the produced items are checked after a production process and that any large deviation is analysed for a root cause. Human handling in this phase can contribute to unreliability and operators must therefore be given the tools to recognise them. Information on expected problems and their effects might help an experienced operator in discovering errors.
Among the reliability activities Aker Solutions could perform are batch tests and analysis of the deviations. Generally this phase should follow the general methodology, chapter 8.
Phase 7 Given that a client has been the commissioning party, maintaining the contact between the Subsea Power and Process department and the client should be easy. Any information about failures, maintenance and repair ought to be easily communicated, but this is not always the case. It will depend on the routines of the client when it comes to reporting of maintenance and repair actions. Normally the client would keep records of most incidents, but the manner of recording differs from one client to another. If the client does report the incidents to Aker Solutions, it is important that the communication is good. There may be a different understanding of the terms and of which incidents are of interest to Aker Solutions. An agreement on the content of the reports and the standards followed should therefore be signed before, or at the beginning, of this phase.
The main activities for the reliability engineer are gathering and analysis of the product performance. The main goal would be to find an expression of the system’s actual reliability and compare this with the desired and predicted reliabilities. Any information thought to be useful for phase 8 or later development projects should be stored in a practical manner. It is suggested that the general methodology, figure 32, is used.
Phase 8 Phase 8 for Aker Solutions should follow the general methodology in chapter 8. The main objective for the Subsea Power and Process department is to learn from the information and use it to improve their reliability programmes. Stored reports on the effect of using a certain reliability method and how it was implemented could save time in the future. Saving time is often said to save money and this phase should therefore not be overlooked.
Appendix D – Aker Solutions PEM The Project Execution Model (PEM) consists of 5 phases and a tender phase. Each phase is split into between 3 and 5 stages where project management and execution is described for each stage. The PEM begins with an opportunity appraisal in phase 1 and ends with the close-out in phase 5. It hence covers the whole product life cycle, but does not follow the five phases discussed in chapter 4; Front-end, Design, Development, Production and Post-production.
For the ERMP the stages in the PEM where studied to see which includes the tasks in the regular Engineering, Procurement and Construction phase. These stages where identified as stages 1D, concept definition, to 4B, system integration test.
The PEM can be studied on the following page, while the ERMP is found in appendix E.
Opportunity
appraisal
M1B
FEASIBLE CONCEPTS
SELECTED
Stage 1A
Feasibility studies
Stage 1B
M1C
CONCEPT
SELECTED
Concept
selection
Stage 1C
M1A
ALTERNATIVES
GENERATED
M1D
CONCEPT
COMPLETE
Concept
definition
Stage 1D
Project Management
• Business opportunity
evaluated
• Products and markets
identified
• First cost estimate and
schedule established
• Scope definition and
scope statement
established
• Identify synergies with
other Aker Solutions and
Aker group companies
• Identify any novel Aker
Solutions and Aker group
company technology
which would add value
Project Execution
• Possible development
solutions established
• Infrastructure identified
• Environmental
requirements identified
• Key interfaces identified
• Possible technology gaps
identified
Project Management• HSE Strategy developed
• Technically &
commercially
feasible concepts
identified• General execution philosophy and strategy established
• CAPEX and OPEX estimate and schedule updated
• Risk assessment for the
alternative concepts
performed
• Involve other Aker
Solutions and Aker group
companies as applicable
• Identify any novel Aker
Solutions and Aker group
company technology
which would add value
Project Execution
• Preliminary field layout
system schematics
established, equipment
list including
spares/back-up, design
basis and technical
solution description
established for each of
the different field concept
solutions
• Main equipment sized
• Preliminary
fabrication/testing/installa
tion method established
• Major completions
aspects affecting the
concept selection
identified
• Screening criteria
defined
• Alternative concepts
ranked
• Clients specification
requirements reviewed
and deviations /
clarifications list
established
• Technology gaps
identified and preliminary
technology qualification
programs identified
Project Management• Preliminary project execution strategy
• Sourcing categories and scenarios determined
• CAPEX and OPEX
estimate and schedule
updated
• Risk assessment
updated
• HSE goals defined
• Involve other Aker
Solutions and Aker group
companies as applicable
• Identify any novel Aker
Solutions and Aker group
company technology
which would add value
Project Execution
• Final design basis
consolidated. Field
layout, system
schematics, equipment
list including spares /
back-up, design basis
and technical solution
description updated
• Concept solution
selected
• Technology gaps and
technology qualification
programs updated
• Analyses (as applicable)
completed to verify the
integrity of the design
solution concept selected
• Clients specification
requirements and
deviations / clarifications
list updated
Project Management• Execution strategy &
schedule finalised• Definitions for potential design competitions established
• Pre-qualification of main Sub-Contractors
• CAPEX and OPEX
estimate and schedule
defined
• Risk assessment
updated
• 1st Priority Packages
identified
• Phase close-out
Milestone Review
• Contract close-out report
when applicable
• Involve other Aker
Solutions and Aker
group companies as
applicable
• Identify any novel Aker
Solutions and Aker
group company
technology which would
add value
Project Execution
• HSE studies and
analyses
• Functional requirements,
overall system
description & layout
established
• Preliminary equipment
list established
• Layout and unit
arrangement finalised
• Fabrication/installation
methods established
• Preliminary testing
philosophy defined
• Technology qualification
program defined
• Completion execution
strategies finalised
• Clients specification
requirements, deviations
/ clarifications list frozen
Phase 1: Feasibility & Concept
M2C
GLOBAL DESIGN
COMPLETE
Project Management• Baseline schedule approved
Project Execution• HSE and safety risk assessment checked
• Engineering for procurement within stage
• POs placed for bulk material and/or LLI
• Qualification program established
• System engineering design • Thermal design analysis • Critical interfaces defined
Project Management
• Risk assessment updated
• Milestones and detailed
construction schedule
verified
• Current estimates updated
• Schedules and budgets
updated for next phase
• Project mgmt. plan updated
for next phase
• Scope changes identified,
agreed and implemented
• Capture lessons learnt from
current phase and update
database
• Supplier plan started
Project Execution
• HSE and safety risk
assessment completed
• System engineering (MEL
and P&IDs) issued for
construction
• System design basis
completed• Engineering for procurement within stage
• POs for all CLLI equipment
placed
• All major interfaces frozen
• All main subcontracts placed
• Mechanical completion
preparation
• Detailed testing program
established
Project Management• Project Charter established / updated
• Project scope defined• Contract reviews performed• Project mgmt. plan (Integration, Scope, Time, Cost, Communication, Risk, Procurement) established / updated incl. execution strategy
• HSE mgmt plan established• Quality mgmt plan established including internal quality audits
• Reporting routines established• Procurement /subcontract strategy defined
• Project schedule, cost
estimate/budgets established• Team alignment program started
• Stakeholder expectation analysis performed
• Consideration of lessons learnt from other projects
• Installation strategy started• Pre-qualification of main Sub-Contractors
• System completion plan started• Warranty provision booked
Project Execution• Preliminary HSE and safety risk identification performed
• Overall project ITPsestablished
• MDL, MEL and P&IDsestablished
• Procurement milestone plan (PMS) established
• Engineering for procurement within stage
• POs for CLLI placed or material allocated from stock
• Draft construction and completion plan established
• Concept design review performed
• System design basis established
• Interface register established • ROV philosophy established • Testing philosophy established• Transportation philosophy established
• Installation philosophy established
System
definition
M2B
LAYOUT & MAIN
STUCTURE FROZEN
Stage 2A
System design & Layout development
Stage 2B
Global
design
Stage 2C
M2A
CRITICAL PO’s
AWARDED
Phase 2: System Definition
Detail design &
Subcontracting
M3B
PRE FABRICATION &
MANUFACTURING COMPLETE
Stage 3A
Pre-fabrication &Manufacturing
Stage 3B
M3C
PREASSEMBLIES
READY FOR SHIPMENT
Assembly
Stage 3C
M3A
DETAIL DESIGN COMPLETE &
SUBCONTRACTS AWARDED
Phase 3: Detailing & Fabrication
Project Management
• HSE & QA audits of
subcontractors performed
and followed up
• System completion plan IFC
Project Execution
• Procured material on site
and in stock
• Manufacturing and
machining completed
• Manufacturing and
fabrication for subcontractor
started
• Sub-assembly and sub-
assembly testing drawings,
procedures and documents
released
• Assembly drawings,
procedures and documents
released
• Start procurement close-out
• All suppliers documents
received and approved
Project Management
• HSE program for
construction updated to
include Phase 4
• Schedules and budgets
updated for next phase
• Project mgmt. plan updated
for next phase
• Capture lessons learnt from
current phase and update
database
Project Execution
• Sub-assembly
manufacturing / fabrication
completed
• Assembly in-house
completed
• Subcontracting fabrication
for minor structures
completed
• All engineering drawings /
documents released
• Close POs
• FAT / EFAT procedure
released
• SAFOP for testing
performed
Project Management
• Milestones and detailed
construction schedule
verified
• Updated project mgmt. plan
implemented
• Team Alignment program
continued• Consideration of lessons learnt from other projects
Project Execution
• System engineering
completed
• Material, BOM, drawings,
data sheets and documents
released for construction
• All reaming POs placed
• Vendor information
implemented in detail design
• POs expediting
• Internal ITPs frozen
RECIPT OF ITT
TENDER PHASE START
(RDG 1)*
TE
KICK-OFF
COMPLETE
Positioning
TA
BID / NO BID
(RDG 2)*
Assess
Stage TA
TB
DRAFT TENDER
Prepare
Stage TB
TC
SUBMIT TENDER
(RDG 4)*
Approve
Stage TC
Business Development
• Prospect ID and
screening completed
• KT Analysis performed
• Core capability strategy
profile (CCSP) checked
• Client contract /
objectives identified
• Winning strategy
established
• Partners and scope
identified
• Tender Accountable
identified
• Prequalification
performed
Project Management• ITT review held
• Tender cost, schedule
and budget established
• KT analysis updated
• Winning strategy and
cost vs. Client
objectives / budget
checked
• Initial project execution
strategy established
• Risk register updated
• Tender team
nominated, including
SLS coordinator
• Bid / No bid• Consideration of lessons learnt from other tenders
Project Execution
• Initial review of ITT
carried out
• Framework of tender
established
• Outline of technical
solution established
• Execution strategy
determined
Project Management• Tender team and kick-off mobilised
• Tender execution strategy, budget and plan established
• Project execution strategy and schedule established
• HSE mgmt. plan established
• Weight and cost estimated
• Organisation defined and key project personnel nominated
• Pricing / compensation strategy and formats established
• Tender clarification / qualifications established
• Risk analysis performed• Drafted tender
Project Execution
• Tender process kicked-
off
• Detailed costing
completed
• Contractual assessment
carried out
• Risk and opportunity
assessment carried out
Project Management• Tender document
reviewed
• Management approvals
done
• Project execution
strategy, organisation
and project team
established
• Cost and cash flow
estimated
• Schedule / MPP
established
• Contract T’s & C’s in
place
• Sub-contract: T’s & C’s
in place
• Mandate and team
negotiated
• Risk mgmt: risk register
and contingency
determination done
• Price and compensation
established
Project Execution
• Tender approved at the
appropriate
management level
• Tender submitted to
client
Tender phase: Tender & Kick off
Tender phase
Negotiate
Stage TD
Project Management• Negotiations done
• Bid clarifications done
• Updated
•Key data
•Price /
contingency
•Risk analysis
•Execution Plan
• Management approval
(RDG 5) done
• Contract ready for
signature
• Hand-over to project
team prepared
Project Execution
• Bid Clarifications done
• Contract reviewed and
signed
Kick-off
Stage TE
Project Management• Project team mobilised
• Tender team hand-over
done
• Client kick-off meetings
held
• Project start-up Plan
(mgmt.) established
(PIP)
• Internal kick-off
meetings held
• Teambuilding planned
• Capture lessons learnt
from current phase and
update database
• SLS project support
plan started
Project Execution
• Tender team hand-over
done
• Start-up check lists
established
• Basis alignment
designed
• *RDG = Risk Decision
Gate
TD
SIIGN CONTRACT
(RGD 5)*(RDG 3)*
FAT / EFAT &
Transportation
M4B
ALL ASSEMBLY
WORK COMPLETED
Stage 4A
System integration test
(SIT)
Stage 4B
M4C
MECHANICAL
COMPLETE
Mechanical
completion
Stage 4C
M4A
ALL PREASSEMBLIES
SHIPPED TO SIT
Phase 4: Testing & Mechanical completion
Project Management
• HSE audits performed and
followed up
Project Execution
• System integration test
(SIT)
• SIT test reports released
Project Management
• Cost, schedule and risk
programs updated
• Updated project mgmt.
plan implemented
• Team alignment program
continued• Consideration of lessons learnt from other projects
Project Execution
• FAT / EFAT completed
• Final documentation index
ready
• Initial mechanical
completion
• Transport after FAT /
EFAT and MC
• System integration test
(SIT) procedure released
Project Management
• Service base ready for
handover
• Handover to SLS and
customer performed
• Equipment handed over to
customer according to
applicable international
standards
• Capture lessons learnt
from current phase and
update database
• Project close-out report
written
• System Completion Plan
updated
• HSE program established
• Schedules and budgets
established
Project Execution
• Engineering: relevant as-
built mark-up performed
• Fabrication work MC
complete and quality
records available
• Completion: categorized
punch lists for all systems
completed
• All systems ready for
installation and
commissioning
• All relevant site activities
documented and MC
completed
• Operation and
maintenance manuals IFC
Offshore services/
commissioning
M5A
OFFSHORE INSTALLATION
COMPLETE
Stage 5A
Mobilise
Stage 5B
M5C
START-UP
COMPLETE
Demobilise
Stage 5C
M5B
SYSTEMS
COMMISSIONED
M5D
TAKEOVER
COMPLETE
Project Management
• All contractual obligations
including completion
certificate closed
Project Management• Install equipment
according to contract
Project Management• Personnel and equipment demobilized
• All contractual obligations for this installation closed
Project Management
• If required by the
contract
• Quote with commitment
from planning and
verification from sales
prepared and delivered
to customer
• PO confirmed
• Personnel and
equipment prepared and
mobilized
Close-out
Stage 5D
Phase 5: System Completion
Subsea - Project Execution Model
Key Stage Objectives
Strategic
Control
Execution
Tools
Testing
& MC
Detailing &
Fabrication
System
Definition
Feasibility
& Concept
Tender &
Kick off
System
Completion
Appendix E – Equipment Reliability Management Programme The Equipment Reliability Management Programme is developed as a part of the Midgard Subsea Compression System project. As a part of the demands to the project, Statoil asked for an ERMP for the EPC phase of the project. EPC stands for engineering, procurement and construction. The phase can thus cover phases 2 to 6 in the eight phase model. Although the original thesis assignment stated that a specific subsystem should be the basis for the case study, it has been agreed that the whole system is more suitable.
The reliability programme follows the ISO 20815 standard and the two methodologies developed in this thesis. The Project Execution Model (PEM) in appendix D has been used to establish the tasks a reliability engineer has to follow in the reliability programme. From the PEM, stages 1D, Concept Definition, to stage 4B, System Integration Test, are considered as parts of the EPC phase. This is also shown in the ERMP.
ISO 20815 demands that the reliability programme is based on a project risk categorisation. An example for the categorisation table was shown in chapter 9 and has been used to develop a more specific table in the ERMP. The purpose of the risk categorisation is to study the necessary depth of the reliability programme. A “low” risk project needs fewer reliability methods and a smaller amount of follow-up, than a “medium” or “high” risk project.
In the ERMP, it has been considered acceptable to use descriptions as “low to medium” and “medium to high” for the risk categorisation. The main reason for this is to be more specific where the risk is concerned. For the Midgard SCS project, the risk is evaluated to be somewhere between medium and high. With this risk level, it is evident that the reliability programme should follow the development tightly and be used to confirm the quality of the design. The Midgard SCS project is performed by a project organisation with good knowledge of the system design and is thus not entirely at a “high” risk level. The main reason why the project is rated above a “medium” risk class is the costs and the newness of the equipment.
To develop a compression system and place it in water is not an entirely new idea. Aker Solutions is currently testing an SCS at Nyhamna in Møre and Romsdal. The SCS is intended for Ormen Lange, but is larger than the one for Midgard. This means that the Midgard SCS does not require all the steps in the Technical Qualification. However, as long as the Ormen Lange SCS has not been finished with testing, the technology has some risks connected to it. This includes a possibility that changes must be done in the design and more time will be spent before it is safely on the seabed. The alternative to a compression system sub sea is to place a compression system on a platform close to Midgard.
The ERMP is a fairly large document and not all parts must be studied in detailed for this master thesis. The appendices can be left out, as can the shorter descriptions about the reliability methods. The former consist of previous failure estimates for an SCS, while the latter has been described in the main report. Of most interest for the thesis are the project risk categorisation (part 3) and the reliability programme activity schedule (part 5).
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Equipment Reliability Management Program Technical Risk & Reliability
Midgard Subsea Compression
10000942820-PDC-000
Client Document Number Client Document Version
Document: 10000942820-PDC-000
Equipment Reliability Management Program Version: 00 - In Work
Technical Risk & Reliability Issue date:
Midgard Subsea Compression Page: 2 of 33
TABLE OF CONTENTS 1. INTRODUCTION ............................................................................................................................. 4 1.1. Background ...................................................................................................................................... 4 1.2. Scope of Work ................................................................................................................................. 4 1.3. System boundaries and life cycle status ......................................................................................... 4 1.4. Distribution ....................................................................................................................................... 6 1.5. Abbreviations ................................................................................................................................... 6 1.6. Definitions ........................................................................................................................................ 6 1.7. References....................................................................................................................................... 7 1.8. Document History ............................................................................................................................ 7 1.8.1. Changes Since Previous Revision .................................................................................................. 7
2. RELIABILITY MANAGEMENT PHILOSOPHY ............................................................................... 8 2.1. General ............................................................................................................................................ 8 2.2. Overall Optimisation Criteria ............................................................................................................ 8 2.3. Performance objectives and requirements ...................................................................................... 9 2.4. Performance measures ................................................................................................................. 10
3. PROJECT RISK CATEGORISATION .......................................................................................... 12 3.1. General .......................................................................................................................................... 12 3.2. Risk categorisation ........................................................................................................................ 12
4. ORGANISATION AND RESPONISBILITIES ............................................................................... 15 4.1. Reliability Organization .................................................................................................................. 15 4.2. Responsibilities .............................................................................................................................. 15
5. ACTIVITY SCHEDULE .................................................................................................................. 17 5.1. General .......................................................................................................................................... 17 5.2. Activities overview ......................................................................................................................... 17 5.3. Reliability activities ......................................................................................................................... 20 5.3.1. Reliability allocation ....................................................................................................................... 20 5.3.2. Hazard identification analysis ........................................................................................................ 20 5.3.2.1. HAZID ............................................................................................................................................ 20 5.3.2.2. SWIFT ............................................................................................................................................ 20 5.3.3. FMECA .......................................................................................................................................... 20 5.3.4. RAM analysis ................................................................................................................................. 21 5.3.4.1. FTA ................................................................................................................................................ 21 5.3.4.2. RBD ............................................................................................................................................... 21 5.3.4.3. Other available tools ...................................................................................................................... 21 5.3.5. Criticality importance measures..................................................................................................... 22
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5.3.6. HAZOP ........................................................................................................................................... 22 5.3.7. Human factors analysis ................................................................................................................. 22 5.4. Relationship between activities ..................................................................................................... 22
6. LIST OF RELIABILITY DOCUMENTS TO BE PRODUCED ........................................................ 24
APPENDIX A FAILURE DATA DOSSIER .......................................................................................... 25
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1. INTRODUCTION 1.1. Background
The Åsgard field lies in 250 – 300 m water depth in the Norwegian Sea, about 200 kilometres off mid-Norway and 50 kilometres south of Heidrun. The Åsgard B platform receives gas production from the Midgard and Mikkel reservoirs, which are connected through a subsea flowline system. Additional pressure support is now required to maintain stable production flow and Statoil has initiated the Åsgard Minimum Flow Project. Aker Solutions has since 2000 been working with Statoil to define solutions for subsea compression and is currently finalising the delivery of the Ormen Lange Subsea Compressor Pilot. Under this pilot project Aker Solutions has delivered a full-scale, marinised subsea compression system. To meet the needs of the Åsgard MFP, Aker Solutions has developed a subsea compression system based on the Ormen Lange Pilot and incorporating specific Technology Qualification Programs performed under the Åsgard MFP.
1.2. Scope of Work The purpose of this document is to outline a reliability management program for the Engineering Procurement and Construction (EPC) phase of the Midgard Subsea Compression Field development. The document will address the following topics:
• Performance objectives and optimisation criteria • Project risk categorisation • Description of responsibilities • An activity schedule including an overview of reliability activities.
1.3. System boundaries and life cycle status The Subsea Compression System (SCS) comprises of a Subsea Compression Station (SCSt) with two compression trains and a Subsea Compression Manifold Station (SCMS). The SCS is illustrated in Figure 1-1.
Figure 1-1: Overview of Midgard Subsea Compression System
SCMS
SCSt
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Each compression train consist of the following modules: • Interface Spool Module • Combined Inlet/Anti-Surge Cooler Module • Scrubber Module • Condensate Pump Module • Compressor Module • Discharge Cooler Module • Compressor Control Module • Active Magnetic Bearing Control Module • Stand-alone Subsea Control Module
Power and Control is supplied to the SCS through 2 combined Power and Control Umbilicals. The umbilicals are terminated in a Transformer and Umbilical Termination Module. Each compression train is installed on an alignment frame that allows for installation of one completed train, as shown in Figure 1-2.
Compressor Train
Transformer and Umbilical Termination
Module
Train Base Frame
Figure 1-2: Compression Train installed on alignment frame The reliability management program has been developed for the EPC phase of a project life cycle and any reliability activities not relevant for this phase have not described in this document. The EPC phase covers the engineering, procurement and construction of the Subsea Compression System. The EPC phase follows after the FEED (Front-End, Engineering and Design) phase is completed. During the engineering phase, the deliverables and documentation needs are identified, and design, material selection and technical specifications are established. When the detailed system design is completed, a procurement plan is established according to specifications. The construction phase covers the manufacturing of all equipment and the assembling and testing of the complete Subsea Compression System.
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1.4. Distribution The Equipment Reliability Management Program is an important document stating the Aker Solutions reliability management system to be implemented for the EPC phase, and will as such serve as a key document for Aker Solutions and the Company with regards to audits and follow up of the Work. The content is specific, and must be adhered to during all phases of the Work. The Equipment Reliability Management Program has been developed within the frames of the ISO 20815 Standard for Production-Assurance Programs, ref./1/, Company requirements specified in the project design basis, Scope of Work, Specifications and the Aker Solutions HSE policy and standards. The Equipment Reliability Management Program will be updated, as required, in connection with the major project phases covering engineering, fabrication, assembly, testing and completion activities. The Equipment Reliability Management Program will be distributed to Company as well as key project personnel, such as Work Package Manager, Project HSE Manager, Engineering Manager and Construction Manager, for information and follow up.
1.5. Abbreviations AMB Active Magnetic Bearing AS Aker Solutions Company Statoil Contractor Aker Solutions EFAT Extended Factory Acceptance Testing EPC Engineering, Procurement and Construction FAT Factory Acceptance Test FEED Front End Engineering and Design FMECA Failure Mode Effect and Criticality Analysis HAZID Hazard Identification HAZOP Hazard and Operability analysis HV High Voltage PEM Project Execution Model RAM Reliability, Availability and Maintainability RBD Reliability Block Diagram SAFOP Safe Operation Analysis SCMS Subsea Compression Manifold Station SCS Subsea Compression System SCSt Subsea Compression Station SCM Subsea Control Module SIT System Integration Test SWIFT Structured What If Technique VSD Variable Speed Drive WP Work Package
1.6. Definitions Availability, Ref./1/ The ability of an item to be in a state to perform a required
function under given conditions at a given instant of time, or during a given time interval, assuming that the required external resources are provided. This ability is expressed as the proportion of time(s) the item is in the functioning state.
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Note 1: This ability depends on the combined aspects of the reliability, the maintainability and the maintenance supportability. Note 2: Required external resources, other than maintenance resources do not affect the availability of the item.
Deliverability, Ref./1/ The ratio of deliveries to planned deliveries over a specified period of time, when the effect of compensating elements, such as substitution from other producers and downstream buffer storage, is included.
Maintainability, Ref./1/ The ability of an item under given conditions of use, to be retained in, or restored to, a state in which it can perform a required function, when maintenance is performed under given conditions and using stated procedures and resources
Production availability, Ref./1/
The ratio of actual production to planned production, or any other reference level, over a specified period of time.
Production assurance, Ref./1/
Activities implemented to achieve and maintain a performance that is at its optimum in terms of the overall economy and at the same time consistent with applicable framework conditions.
Reliability, Ref./1/
The ability of an item to perform a required function under given conditions for a given time interval.
1.7. References 1. ISO 20815 Petroleum, petrochemical and natural gas industries - Production assurance
and reliability management, First Edition, 01.06.2008 2. Åsgard Minimum Flow - Book 051.003-02 Functional Design Requirements - Midgard
Subsea Compression 3. Aker Solutions, General System Specification and Description, 10000942822 4. Aker Solutions – Test and Fabrication Philosophy, 10000942834 5. IEC 61882 Hazard and Operability Studies (HAZOP Studies) - Application Guide 6. Rausand & Høyland, 2004, System Reliability Theory; Models, Statistical Methods and
Applications. Wiley 7. Murthy et al. 2008, Product Reliability, Springer
1.8. Document History Version Description of Changes
00 Issued for Company Review
1.8.1. Changes Since Previous Revision
Cause of change Description of Changes Comment
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2. RELIABILITY MANAGEMENT PHILOSOPHY 2.1. General
The reliability management philosophy describes the overall optimisation criteria for the Engineering, Procurement and Construction (EPC) of the Midgard Subsea Compression System (SCS). The philosophy also defines the performance objectives and requirements, as well as the performance measures.
2.2. Overall Optimisation Criteria Previous studies show relatively high production availability for Subsea Compression Systems. It is important to use availability and reliability analysis methods throughout the design phase and in particular in the early phases, in order to obtain an optimal design with regard to availability. The optimization process can be performed as illustrated in the ISO 20815 standard, Figure 2-1.
Figure 2-1: ISO 20815 Optimisation Process
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High production availability depends on the following: • Inherently high reliability of the individual modules, can be achieved by a internal
redundancy on the components with the highest failure rate -> fault tolerance • High maintainability, effective intervention, modularization and sparing philosophies • High fault tolerance, through either overcapacity in the system, i.e. the potential to
maintain a percentage of the production upon failure in one compression train, or high redundancy
In order to reach a high reliability for the Subsea Compression System, the following optimisations should be considered:
• Implementation, development and improvement of the Ormen Lange design for Subsea Compression
High inherent reliability through:
• Optimisation of the equipment lifetime • Reduction of the number of wet mate connectors • Reduction of the number of disconnect/connect operations of wet mates
o Stand-along SCM instead of pump SCM (to avoid disconnects when retrieval of pump module)
o AMBC separately retrievable • Built-in redundancy in the system • Completely redundant control system (A and B system)
o Cross-connection between UPS A and UPS B → each can run both trains
• Reduced downtime through effective sparing philosophy --> Capital spares must be available for the most critical items. If no spares are available the mean time to repair will increase substantially. When a spare is available the expected active repair time will be reduced to a couple of days (retrieve and replace on site). If no spare is available the active repair time may vary from a couple of months to a year.
High maintainability through:
• Optimisation of module weights according to weight limits of vessels --> Long mobilization times will cause excessive downtime and lost production. Mobilization times larger than one month for critical equipment intervention is not recommended.
• Effective modularization philosophy--> The modules that are most likely to fail should be easily/separately retrievable
o Control functionality easily retrievable, separately retrievable SCMs, AMBC and junction boxes
o Low complexity of control functions on heavier modules, such as Scrubber and Transformers
• Allow for continued production in one train during failure/intervention on the other train High fault tolerance through:
• Overcapacity in the system: Compressor is bottle neck – capacity on each train is maximised accordingly. A rest capacity of more than 50% on one train will reduce failure effect
• Condition monitoring -> early detection of latent failure -> early mobilization of spares
2.3. Performance objectives and requirements The objective of the reliability management program is to ensure that the reliability of the Subsea Compression System is not compromised during the EPC phase, and to ensure the highest possible inherent reliability of the system during later life cycle phases. The correct handling of safety and production aspects, as well as reduced economic risk, is a desired goal.
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The basic equipment reliability management philosophy is:
• A fault is a defect, imperfection, mistake or flaw of varying severity that occurs within and affects the operational ability of the SCS.
• All hazards shall be identified and evaluated for criticality • All critical failures shall be reviewed through MTTF (mean time to failure) and MTTR
(mean time to repair). • Requirement to design is that the predicted reliability meets the desired reliability within
acceptable limits. • All relevant failure events and faults shall be simulated as close as possible to realistic
operations. • All components and sub-systems shall be listed according to criticality/importance. • Testing of materials and equipment shall be performed for confirmation of predicted
reliability. • Documentation of reliability methods used and analysis results must be prepared.
The verification of these requirements is done through the acceptance of results performed in the reliability management program. Later verification is obtained through the field experience and performance.
2.4. Performance measures The requirement to availability is given in the Functional Design Requirements, ref./2/, as:
• The subsea compression system shall aim for process and system designs, which maximises the production availability.
• For calculation purposes, the production availability shall be calculated as the ratio of production to planned production over the initial 10 years of production.
• The production availability evaluation shall include lead- and down time due to repair activities, but not external causes such as loss of power supply from Heidrun.
In order to evaluate the performance of the Midgard Subsea Compression Station, the following performance measures will be calculated:
• Production availability • System availability • Deliverability • Proportion of time the production is equal to or above demand • Proportion of time the production is zero • Proportion of time the production is below demand • Intervention frequency • Spare utilization • Estimated time for first failure • Sub-system and component criticality
During the previous FEED phase for Midgard Subsea Compression the average production availability was predicted to an average of 94.92 %, giving a production unavailability of 5.08 % The availability calculations were performed at a very detailed level, taking into account failures of all parts of the control system (jumpers, connectors, juntion boxes, etc.) as well as the effect of only having one spare for each module type. The dominating contributor to the production unavailability was the compressor module. A total of 7 equipment types contributed to about ¾ of the system unavailability. These components were:
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1. Compressor module 2. AMB control system 3. Condensate Pump Module 4. Scrubber module 5. SCM Compressor 6. HV connection systems for compressor 7. SCM Pump
The overall production availability was relatively high. This was mainly due to the following: − Inherently high reliability of the individual modules caused by internal redundancy on the
components with the highest failure rate (process sensors, control modules etc) − High maintainability, due to effective modularization philosophy and shallow water depth
It was identified that it was possible to increase the availability by 1.15 % to 96.07 %, if the three most critical components were provided with two spares instead of one spare, thereby reducing the downtime caused by shortage of spares. For the EPC phase the availability calculations should be updated to reflect all design changes. Accurate production profiles should be used to estimate the overcapacity in the system, as this will to a large extent influence the production availability results. It is recommended to evaluate if it there is a potential for increasing the production capacity of the compressors further. The data dossier for the Midgard Subsea Compression System is attached in Appendix A to this report. The failure data is, however, uncertain and should be confirmed as part of the EPC phase. This is in particular true for the main contributors; compressor, the electric jumpers and the HV connection system. Vendor data should be acquired and verified for the jumpers and HV connection system. The compressor unit should undergo a detailed FMECA to confirm the assumptions made with regard to the compressor failure data.
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3. PROJECT RISK CATEGORISATION 3.1. General
The effort needed for the reliability management program is linked to the technical risk of the project. The higher the technical risk category of the project, the more effort should be put into follow-up and handling of reliability activities. The project risk categorisation has been performed based on the scheme described in section 4.3.2 of ISO 20815, ref./1/.
3.2. Risk categorisation The categorisation of project risk provides a guideline with regard to how the equipment reliability management program should be implemented. It is reasonable to believe that a project with low risk will be open to more slack concerning the implementation of reliability activities, while a high risk project needs extra attention to reliability in order to succeed. ISO 20815, ref./1/, suggests that project risks can be separated in three main classes, see Table 3-1:
• Low risk • Medium risk • High risk
Table 3-1: Project Risk Categorisation Matrix (ref./1/)
Technology Operating envelope
Technical system scale and complexity
Organisational scale and complexity
Risk class1 Description
Mature Technology
Typical operating conditions
Small scale, low complexity, minimal change of system configuration
Small and consistent organisation, low complexity
Low
Low budget, low risk project using field-proven equipment in the same configuration and with the same team under operating conditions similar to previous projects.
Mature Technology
Typical operating conditions
Moderate scale and complexity
Small to medium organisation, moderate complexity
Low or medium
Low to moderate risk project using field-proven equipment in an operating envelope similar to previous projects but with some system and organisational complexity
Novel or non-mature technology for a new or extended operating environment
New, extended or aggressive operating environment
Large scale, high complexity
Large organisation, high complexity
Medium or high2
Moderate to high risk project using either novel or non-mature equipment or with new or extended operating conditions. Project involves large, complex systems and management organisations.
1 The term ”low or medium” indicates that projects comprising the indicated features can be classified as either low-risk or medium risk projects, likewise for the term ”medium or high”. 2 The novel or non-mature technology should have a potential significant impact on the project outcome to be classified as high risk
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The evaluation of the different categories for Midgard SCS has been done on a sub-system level. The project risk categorisation matrix has been extended to include also a column on reliability. The results are summarized in Table 3-2. Table 3-2: Evaluation of technical risk categories for Midgard SCS
Sub-System
Technology Reliability Operating envelope/ environment
Technical system scale and complexity
Organisational scale and complexity
Risk class Description
HV Power Supply system
The topside parts of the HV power supply should be considered as proven technology. The subsea transformer technology is also standard technology that has been used previously in both subsea and topside projects. The level of current and voltages is secondary with regard to qualification of a subsea transformer. HV connection system solutions qualified through Ormen Lange and Midgard TQPs may be used, however, no previous subsea experience exists with connection systems of this rating.
Little or no experience data exists for the subsea components and it has been difficult to get a qualified estimate for the reliability of these systems. The HV wet mate connections are believed to be critical with regard to reliability.
Parts of the system are topside, other will be marinized. No experience with HV connection systems at this rating for subsea applications, however, experience will be achieved through operation of the Ormen Lange Pilot at Nyhamna.
The Midgard HV power supply system is of a lower complexity than the power supply system for Ormen Lange due to less subsea electronic equipment. However, this is still a complex system compared to standard subsea production systems.
The Aker Solution subsea organisation has worked on similar systems in previous projects such as the Ormen Lange Pilot. The Ormen Lange organization is closely integrated with the Midgard project team.
Moderate The HV power system has been developed for previous projects, but some parts are not yet considered mature in the subsea context, this is particular valid for the HV connection system for the compressor.
Process system
Technology assessment sessions carried out for the Midgard SCS has concluded that the main technology gaps for the process system are related to the Compressor Unit. The assessment concluded that:
Gas-Liquid separation and liquid pumping are considered well proven from existing applications and do not need special attention. The subsea compressor is, however, considered new technology, in particular if MAN Turbo is the chosen supplier. Ormen Lange has qualified a GE compressor for subsea application, however, no operating experience exists for this technology.
No experience data exists for subsea compressor, but data from topside applications indicate that the reliability of these components is fairly low. It is therefore imperative to improve the reliability of this equipment through design for subsea applications.
Compressors are in use topside, but no operating experience with these systems exist subsea. Testing at Nyhamna of the Ormen Lange Pilot will be useful input for the Midgard SCS, however, the compressor supplier may be different for Midgard than for Ormen Lange. The MAN Turbo compressor has been tested at K-Lab with wet gas, however, qualification with regard to marinisation of the compressor (casing design) is required.
The process system should be considered as a high complexity project. Little experience with marinisation of rotating equipment at this scale.
The Aker Solution subsea organisation has worked on similar systems in previous projects such as the Ormen Lange Pilot. The Ormen Lange organization is closely integrated with the Midgard project team.
Moderate to high.
The equipment is relatively new and some qualification items still remain. No operating experience exists subsea for this type of systems, however, experience will be gained through the Ormen Lange Pilot testing at Nyhamna. The project organisation is not overly complex and has worked on a similar development before.
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Control system
The qualification of the control system has been completed for the Ormen Lange project, this qualification is for most parts transferrable to the Midgard project. There are, however, some outstanding qualification issues for Midgard. The risk related to these qualifications is however, estimated to be limited.
Experience data exists for a large part of the control system components, even if all-electric control systems of this scale has not been implemented for subsea application. In general the availability of this system should be considered to be fairly high due to high internal redundancy.
There is limited experience with all electric control system; however, experience exists with some of the components used in the system.
The control system stretches from topside platform to the seabed and is fairly large. The system is composed of a high number of jumpers and connectors and should be regarded as complex.
The Aker Solution subsea organisation has worked on similar systems in previous projects such as the Ormen Lange Pilot. The Ormen Lange organization is closely integrated with the Midgard project team.
Moderate The control system consists of parts that are already in use subsea and the risks for these are fairly well known. Qualification has been performed and concluded successfully through the Ormen Lange Pilot project, however, there are some outstanding qualification issues to adapt the system to Midgard SCS.
The overall project risk categorisation is somewhere between moderate to high. Some parts of the system are close to “off-the-shelf” and well know, while the compressor and other modules have never been applied subsea before. The Aker Solution subsea organisation has worked on similar systems in previous projects such as the Ormen Lange Pilot, and this organisation is working closely integrated with the Midgard project team. In order to develop an appropriate equipment reliability program for the Midgard Subsea Compression Project it is considered that the project needs a thorough follow-up for reliability, as for medium to high risk project. This is based on the novelty of some of the equipment and the fact that the subsea compression system is being developed slightly differently for Midgard than for Ormen Lange.
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4. ORGANISATION AND RESPONISBILITIES 4.1. Reliability Organization
Reliability is a management and line responsibility. The reliability/safety manager and reliability engineers will operate in a network with the objective to maintain a high focus on reliability throughout the design and manufacturing of the system in order to obtain solutions that ensure an optimal availability of the system. The reliability management project organization is shown in Figure 4-1 below. In addition, the elected safety delegates at each work location will play an important role and are considered part of the reliability network.
Project Engineering TBN Manager
Reliability ManagerTBN
3rd party HAZOP, HAZID facilitators
TBN
Control Systems WPs
HV Power Systems WP
Process Systems WPs
Tie-in & Manifold WP
WP Engineers
Relaibility EngineersSystem Enginnering Group
Figure 4-1 Reliability Project Organisation Midgard SCS
4.2. Responsibilities The Project Engineering Manager (Aker Solutions) The Project Engineering Manager holds the overall responsibility for the system design. He/she will be responsible to ensure an optimal design with regard to reliability and to ensure that all reliability activities are coordinated with other project activities.
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The Reliability Manager (Aker Solutions) The Reliability Manager is responsible for assisting the Project Engineering Manager, the HSE Manager and other project personnel in reliability matters. The Reliability Manager holds the overall responsibility for managing and coordination of the project reliability activities. He/she shall manage the daily execution of reliability related activities within scope of work, and as outlined in the reliability management program. Reliability analysis engineers The reliability analysis engineers are responsible for performing reliability analyses and follow-up of findings/results throughout the project phases. They are also responsible for the preparation of the RAM and Risk analyses as input to the total field RAM and Risk analyses performed by Company. Other Managers and Leads All project line managers, work-package leads and lead engineers are responsible for reliability within their own area. They are responsible for contacting the Reliability Manager when assistance is needed. Engineering manager and work-package leads
are responsible for ensuring that the reliability aspects are included in design work. This includes the responsibility for identifying applicable authority acts and regulations. Activities such as design reviews, hazard and operability analyses (HAZOP), etc. shall address and include reliability aspects as defined by regulatory- and contract requirements. Adequate reliability requirements in technical specifications to suppliers shall be ensured.
Procurement manager
has a responsibility to ensure that the appropriate reliability requirements are included in purchase orders with suppliers and sub-contractors.
All team members • All team members are responsible for reliability and must in this respect execute a
personal responsibility.
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5. ACTIVITY SCHEDULE 5.1. General
The activity schedule is presented according to the steps in the Aker Solutions Project Execution Model (PEM) for the Engineering, Construction and Procurement phase of the project. The activities schedule maps the reliability activities against the project milestone phases. The reliability activities are dedicated to particular phases based on the knowledge assumed available for the system at that point in time.
5.2. Activities overview The activities that should be included as part of the reliability management program for the EPC phase of the Midgard Subsea Compression Project, are shown in Figure 5-1. Figure 5-1 shows the relationship between different engineering, construction and procurement activities and proposed reliability tasks. For each task different tools may be chosen, depending on what is optimal for the system throughout the EPC phase. The black arrows show the next step in the program, while the blue arrows show the inputs from/ outputs to the engineering activities. The Aker Solutions PEM is represented on the left side. The reliability management program includes testing before and after the equipment has been assembled into subsystems and systems. The test methods are described in the Test and Fabrication Philosophy, ref./4/.
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Figure 5-1: Reliability Program Activities as part of the EPC phase for Midgard SCS
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5.3. Reliability activities The following sub-chapters give a description of all methods and tools that can be applied in order to evaluate the reliability during the EPC phase. No activities outside the EPC phase will be presented here.
5.3.1. Reliability allocation Reliability allocation deals with the setting of reliability goals for individual sub-systems such that an overall specified reliability goal can be met. The complexity, criticality and achievable reliability for individual sub-systems are among the points that may be used as a basis for the allocation. Reliability allocation usually starts from a base of past experience and is first performed at a fairly high level. Through the decomposition of the system and the overall required reliability, each subsystem and component will allocated a required reliability. A good allocation of the reliability will help the design process in giving pointers as to where extra measures must be taken in order to obtain the necessary reliability.
5.3.2. Hazard identification analysis A hazard identification of some sort must be performed at an early stage of the system design process in order to identify the potential hazards related to the system. Several methods exist for this purpose and a choice may be based on the type of hazard that is to be searched for. The identification will serve as a basis for implementing design changes and provide valuable input to operational manuals. For the Subsea Compression System, which consist of novel technology, hazards which have been unproblematic in previous development projects may be of importance. It is thus important to perform a thorough hazard identification.
5.3.2.1. HAZID
The HAZID is the most common hazard identification tool, based on a worksheet model. Potential accidental events are evaluated one by one through the study of their probable cause, major effects, and if possible, a ranking of severity and preventive measures. The outcome of the HAZID will be a list of all relevant hazards associated with the system subject to the analysis/study. The environmental risks/aspects of the design shall also be addressed.The HAZID methodology has been applied in the previous phases of the Midgard SCS project and can be easily implemented as part of the EPC phase.
5.3.2.2. SWIFT
The SWIFT is a brain-storming technique where questions beginning with “what if…?” and “How could…?” are asked. A group goes through the system part by part, but on a rather high level. Where the HAZID may go backwards from an event, the SWIFT can go forwards from an action that causes an undesirable event to take place. It can be especially useful for environmental risk assessments and human factors.
5.3.3. FMECA The failure mode, effect and criticality analysis gives an overview of the possible failures that may occur during the system’s operational lifetime. The FMECA is often the first step of a system reliability study and is commonly used in the evaluation of technical equipment. The FMECA is performed in the design phase of a project as a qualitative analysis. The FMECA method involves reviewing as many components, assemblies and subsystems as possible to identify failure modes, causes, and effects of such failures. Although the FMECA is often finalised with the completion of the detailed design, it is possible to continue filling in failure modes and effects throughout the product life cycle. As a tool, it can be particularly useful as an overview of the problems possibly encountered by the SCS.
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5.3.4. RAM analysis The RAM analysis considers the overall reliability, availability and maintainability. Reliability and availability are tightly connected through their definitions. While reliability predicts the system’s ability to function over time, availability measures the actual time in operation against the time the system is meant to operate. The MIRIAM Regina simulation software is often used for modelling and analysis of production systems. MIRIAM Regina is a commercial software package developed in close cooperation with Norwegian oil companies and has been used for several field development studies. The results are based on stochastic simulations and are subject to uncertainties caused by both input distributions (statistical reliability models) and simulation variability. The following approach is applied to perform RAM studies using the MIRIAM Regina tool:
- Definition of study objective, approach and metrics - Definition of study boundary, assumptions and limitations - Identification of main failure modes and corresponding effects (often through previous
FMECA) - Definition of reliability input data on component/module level (failure rates and MTTF,
can be found through detailed assessments of each component through FMECA, FTA and RBD - see descriptions below)
- Definition of repair requirements, repair time and intervention vessel mobilization time - Establishment of a base case availability simulation model (Miriam Regina) - Running of simulations, including sensitivities for different concepts - Generation and interpretation of results, e.g.:
Average Production Availability Subsystem criticalities
- Generation of conclusions and recommendations for further work The estimation of reliability of sub-systems can be performed using techniques such as Fault Tree Analysis (FTA) and/or reliability block diagrams (RBD).
5.3.4.1. FTA
The Fault Tree Analysis is a top-down method where one failure event is broken down into the initial failures. It shows the possible combinations of failures that may lead to a large failure affecting the system’s ability to function as normal. It can also be used in order to calculate the probability that an event will occur, through the probabilities of the basic failures. While the SCS is still in the engineering phase, it can be possible to alter the design if a common failure is shown to propagate rapidly towards a functional failure for the entire system.
5.3.4.2. RBD
Reliability block diagrams are used to show how the different components, assemblies and subsystems are connected. It describes the function of the system and can therefore also show the failure combinations that will lead to a system failure. The minimal cut sets and the most critical failures may be found through this type of diagram. For the SCS this can be useful in order to discover where boosting or redundancy is of particular necessity.
5.3.4.3. Other available tools
FTA and RBD may be used together or instead of each other. There are many methods which can be used for RAM analysis and among them are:
• Markov models • Event tree analysis
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5.3.5. Criticality importance measures The importance of one component or subsystem depends on the system’s ability to function without it. A failure may stay unnoticed, weaken the system, or cause a downtime of the whole system. An importance measure can help rank the components and subsystems based on their effect on the system if they fail. The measure can be very useful in prioritising maintenance operations. Several methods for measuring this exist:
• Birnbaum’s measure • The improvement potential • Risk achievement worth • Criticality importance
5.3.6. HAZOP The Hazard and Operability analysis can be used to study which hazards the system may present towards its environment, surrounding equipment and personnel through its operational modes. It can also identify the problems which prevents an efficient operation. The operational modes can be production, intervention, work-over etc. Through HAZOP studies it is proven that the system design allows for safe and effective operations. HAZOP studies are an integral part of the project activity from a project review point. The HAZOP method applied at Aker Solutions is according to IEC 61882 “Hazard and operability (HAZOP)” studies, and is normally chaired by a third party HAZOP leader.
5.3.7. Human factors analysis A human factors analysis can be performed in order to see how a human interacts with the system. The human being is highly unpredictable and likely to do small errors which can have an impact on the system’s ability to function as normal. A human factors analysis aims to improve operational performance and safety in relation to the system. Human factors are particularly relevant during the manufacturing and assembly phases of the project. It is important to identify and eliminate as far as possible any manufacturing or assemble mistakes that may decrease the reliability of the system when put into operation.
5.4. Relationship between activities Figure 5-1 does not to a full extent show how all the activities are connected through necessary input. Some activities need input from previously performed activities; this is in particular true for the RAM analysis that requires input from a FMECA. Reliability analyses such as FMECA, HAZID, HAZOP and RAM have been performed as part of the FEED phase of the Midgard Subsea Compression System project. However, all of these analyses must be updated to reflect design changes to the system. At the start of the EPC phase, it is recommended to perform a reliability allocation for all the subsystems. The main inputs to this allocation process are the reliability requirements, the information about where high reliability is needed and the design architecture. It is recommended to perform hazard identification and FMECA early in the design phase to give input to reliability improvements. Performing these activities after the reliability allocation will corroborate the allocation; however, the outcome of these analyses may also cause a need for an update of the allocation. A detailed availability/RAM analysis of the system shall be carried out as part of the design phase in order to contribute to optimisation of the system design. The RAM analysis may be used to run sensitivities to evaluate the effect of different system designs on the overall availability.
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In order to get the best possible results from the RAM analysis it is important to spend time developing a detailed failure data dossier, i.e. update the data dossier included in Appendix A to this report. For components and sub-systems where the experience data is scarce, methodologies such as Fault Tree Analyses, FMECA and RBDs can be used to estimate the reliability of the component/sub-system. The RAM analysis gives an overview of the criticality of different components/sub-systems. Further evaluations of component criticality can be performed. The criticality importance of one component or subsystem depends on the system’s ability to function without it. Based on the outcomes of component criticality evaluations it is possible to give input the need for design changes in certain components, such as increased redundancy at a component level. The RAM analysis and criticality importance evaluations shall be updated as the design changes and a final version shall be carried out upon design freeze to confirm that the production availability is in compliance with requirements. The criticality importance evaluations made as a part of this final report can be applied for final input to the sparing philosophy. HAZOP studies should be carried out at an early stage to give input to design changes based on the outcome of the HAZOP. The HAZOP should also be updated as the project approaches design finalization to ensure that no new hazards have been introduced as part of the updated design. For the manufacturing and assembly phase the design is frozen and final RAM, FMECA and HAZOP reports will have been issued. It is, however, important to follow up the reliability with regard to the manufacturing and assembly activities. Procedure HAZOP/FMECA should be performed for each process to ensure that no additional failure modes are introduced to the system as a result of the manufacturing and assembly processes. Human factors analyses may be used to evaluate the human interaction with the system as part of the manufacturing and assembly processes. The physical testing of equipment can only be planned when the manufacturing plans are prepared or completed. When it is known how the system will be manufactured, assembled and tested, it is possible to decide which test results must be obtained for reliability purposes. In order to decide this, it is useful to go through the previous analysis results. Without such a preparation, important information may be overlooked. The recommended test should be based on an evaluation of what type of testing is required to study specific hazards to the component or system functions.
Overall testing of the system cannot be done on the purpose of harming the system, but in order to show that the system functions as expected. Any minor problems occurring must be analysed and followed up. At the end of the EPC phase all reliability documentation is gathered. This will provide information on how maintenance tasks may be prioritised and what type of reliability feedback Aker Solutions should ask for.
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6. LIST OF RELIABILITY DOCUMENTS TO BE PRODUCED The Table 6-1 below represents list of reliability documents to be produced for the EPC phase of the Midgard Subsea Compression Project. Table 6-1 List of reliability documents to be produced
Document Description
Reliability allocation, included in RAM analysis report
Reliability allocation, background for allocation and allocation method.
Reliability program, issued as separate report Schedule including methods, dates and reports for delivery.
Hazard identification, HAZID report Method descriptions and results.
HAZOP, HAZOP report Final analysis and previous results included.
FMECA, FMECA report Final analysis and previous results included.
RAM analysis report Analysis overview, FTA, RBD and regularity analysis included.
Criticality importance analysis, included as part of RAM analysis report
Document should include what the chosen method for criticality measures, and lists of critical sub-systems and components ranging from most critical to least critical.
Human factors analysis, issued as separate report All factors should be listed according to their possible negative effect on the manufacturing, assembling and testing. Measures which may decrease the impact of such factors should also be included.
HAZOP for the manufacturing procedure, Procedure HAZOP
Document describing how the manufacturing process may affect the reliability negatively. Possible measures for avoidance of problems should be included.
Failure modes for manufacturing, used as input for manufacturing procedures
All failure modes discovered should be described with respect to their origin, effect and possible solution.
FAT/EFAT - summary of findings related to reliability
A document should be written about the discoveries in the FAT/EFAT that affects the reliability of the subsea compression system. Both positive and negative effects are to be included. It should also be stated why the effects occurred and whether it is thought that the effects are probable to occur under normal circumstances.
System integration test analysis - summary of findings related to reliability
Any results of the system integration test which are of interest to the system reliability should be documented and commented on according their effect on the reliability.
If it is thought necessary, a summary of these documents could be made describing the changes in the reliability estimates throughout the EPC phase. A comment on how the reliability after testing corresponds with the estimates may also be of interest.
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APPENDIX A FAILURE DATA DOSSIER
Component Name MTTF Data Source OREDA Filter Failure Modes Comment
Process System
Manifold Piping 3048 OREDA 24 Subunit = Manifold AND Component = Piping (hard pipe)
-
No registered failures registered for 233 units.
It is assumed that ½ a critical failure for manifold piping will happen during the next year of operation.
Mechanical Connector 1351 OREDA-2002. pg. 804 Connector – Common Components Subsea
External Leakage Other
3 failures registered for 606 units. Only 1 failure registered as critical. Critical failure rate is thus 1/3 of total failure rate
OREDA 24 has registered 0 failures for connectors
ROV Isolation Valve 1389 OREDA 24 Component = Valve. Process isolation AND Actuation = Manual
Fail to open/unlock Leakage in closed position
3 failures registered for 190 units. 67% of the failures are regarded as critical. None of the failure modes are critical for ROV valves that are normally open during production. It is assumed that ½ a critical failure for normally open ROV valves will happen during the next year of operation.
The critical failures for an closed ROV valve is not assumed critical during normal operation and closed ROV valves are therefore not considered in the RAM analysis.
El. Isolation Valve including Actuator
1389 OREDA 24
Component = Valve. Process isolation AND Actuation = Electric Rotating
- No failures are registered for valves operated by electric rotating actuators.
- OREDA 24 Component = Valve. Process isolation
Fail to open/unlock Leakage in closed position
3 failures registered for 478 units. None of the registered failure modes are critical for normally open valves. For normally closed valves the leakage in closed position is critical during operation and accounts for 1 of the failures.
1489 (crit) OREDA-2002. pg. 804
Valve Process isolation – Common Components Subsea
External leakage process medium Spurious operation
18 failures registered for 898 units. 72% of the failures are regarded as critical. However, for normally open valves, only the external leakage of process medium and spurious operation is regarded as critical. 3 failures are registered for external leakage and 1 failure for spurious operation. This accounts for 22% of the failures.
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Component Name MTTF Data Source OREDA Filter Failure Modes Comment
25
A Scandpower study present RAM estimates for anti surge actuator, 100 Nm rotating actuators and 2.7 kNm rotating actuators. The estimates range from MTTF 23.5 years to MTTF 25.6 years. As an approximation, MTTF 25 years are used for all actuators as was previously applied in the DNV report.
Check Valve 162 OREDA-24 Component = Valve, Check Plugged/choked 1 critical failure registered for 92 units.
Scrubber 50 OREDA-2002. pg. 457 Scrubber, Topside External leakage Structural deficiency Others
No relevant data basis on subsea scrubbers. Topside data for scrubbers considered for relevant critical failure modes (“external leakage”, “structural deficiency” and “others”). “Instrument failures” will be treated separately, hence disregarded here. “Parameter deviation” not considered relevant.
It is furthermore assumed that the subsea design will be more robust than a topside design and that the requirement with regard to separation performance/quality is lower than topsides, thus reducing the number of calibration valves contributing to failure to an insignificant number. The contribution to failure from these valves is removed from the critical failure rate. The structural deficiency failures are reduced by 90% because of increased QA/QC requirements for subsea manufacturing.
Scrubber Level Detectors 98
Tracero: “Level Monitor: reliability. Failure rates and modes”. Doc no. IA0086 (March 2003)
- -
Radioactive source is not retrievable, and requires retrieval of scrubber upon failures. The only failure mode considered relevant for the source is mechanical failure, and should be negligible or at least covered by failures of vessel internals.
Detector unit is mounted on a retrievable plate. Vendor data indicate an MTTF of 9.8 yrs.
This estimate seems reasonable considering the potential level of redundancy. A final estimate depends on operational requirements to accuracy (which may reduce redundancy), but level of redundancy could be increased further by adding detectors.
Given that the level of redundancy is high and that each detector is
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Component Name MTTF Data Source OREDA Filter Failure Modes Comment
separately retrievable it seems reasonable to state that the only relevant failure is common cause failures. OLF Guideline 070 gives a beta-factor of 10% for common cause failures on subsea transmitters.
DP Cell - - The DP cell is not considered critical in previous studies performed by Aker Solutions. The nucleonic sensors are considered to be the main sensors for liquid measurement and the DP Cell is only used for back up.
Magnetic Bearing System Compressor 27.3
S2M – MTTF report for topside MBCM system
- Critical
The magnetic bearing system has been evaluated by vendor and the failures have been split in to failures in control pod and failures in mechanical parts. The total failure rate of the MBCM system is estimated to be 5.1 years. Failures in the mechanical parts include bearing failures, position indicator failuresm temperature sensor failures, and speed sensor failures, and will require compressor retrieval. These failures account for about 1.9% of the total failure rate (when the jumpers are treated separately)
Compressor 8,5 OREDA-2002, page 84 Compressors, Centrifugal, Electric Driven (3-10 MW)
All critical failure modes: External Leakage-Process Medium Fail to start on demand Internal Leakage Low output Spurious stop Vibration
The only failure mode not included is the external leakage utility medium as no utility medium is applied subsea.
No relevant data basis on subsea compressors. Topside data for compressors considered for relevant critical failure modes Data for compressors of 3-10MW was applied due to a too small population (and thus statistical unreliability) for the compressor of 20-30MW.
The subsea design of the compressor is different from the topside design. There are no power transmission elements, lubrication system or shaft seal system. The contribution to failure for each of the equipment units in a compressor is described for centrifugal compressors in general (pages 70-75). It is assumed that the contribution from different units will be the same for all centrifugal compressors. The contribution from the elements not included in the subsea design was removed from the total critical failure rate. In addition to the systems above the contribution from the bearings, valves and control units were removed as they are treated separately in this analysis.
The removal of the non relevant items and the items treated separately resulted in a 70% reduction in failure contribution.
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Component Name MTTF Data Source OREDA Filter Failure Modes Comment
It is therefore concluded that the critical failure rate of a subsea compressor will be 30% of the critical failure rate for a topside compressor (not included the failure rate for external leakage utility medium)
Electric motor, compressor 5.6
Ormen Lange Pilot project, study performed in cooperation with Client
- Critical Magnetic bearing failures and penetrator failures are not included in this estimate.
PSD Sensors 124 OREDA-2002. pg. 811
Subsea Control System – Combined Pressure and Temperature Sensor
Erratic output 1 critical failure registered for 30 units.
Flow meter for anti-surge control 650 OREDA-2002. pg. 811 Subsea Control System –
Flow Sensor - No critical failures registered for 35 units. OREDA-2002 estimated failure rate has been used
Anti-surge actuator 22,8 Vendor data - -
Vendor has 3rd party reliability analysis for actuator suggested used on Midgard Maintenance and degree of criticality of failures in redundant modulating motors uncertain, but most conservative approach estimates an MTTF of 22.8 yrs.
Anti-surge valve 89 OREDA-24 Component = Valve, Control Plugged/choked
4 failures registered for 69 units. 75% of the failures are regarded as critical.
Check the data from Mokveld for next phase
Cooler 84 OREDA-2002. pg. 398 Heat exchangers – shell and tube
External leakage Structural deficiency
No relevant data found for subsea coolers. The passive cooler is basically just pipe segments and does not include a body/shell. Topside data for shell and tube coolers have been studied. It was decided to use the contribution to the critical failure rate from the piping of a shell and tube cooler. In addition it is assumed that the subsea design will be more robust than the topside design, however, it may be somewhat more prone to damages due to vibration. The critical failure rate has, based on the evaluations above, reduced by 30%.
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Component Name MTTF Data Source OREDA Filter Failure Modes Comment
Condensate pump unit w/ el motor 6.1
KOP FMECA. LiquidBooster. TU Z0900-230009-2
- - A FMECA, done in conjunction with the Tordis Project, has evaluated failure modes relevant for subsea application in order to estimate MTTF. This estimate includes el motor.
Recirculation Choke Valve 32 OREDA-2002. pg. 833 Wellhead and X-mas tree
– Choke valve
Fail to function on demand Fail to close Others Plugged/choked Fail to open
22 failures registered for 75 units. 7of the failures are regarded as critical.
OREDA-24 has registered no critical failures for choke valves
MEG Piping 309 OREDA-2002. pg. 804 Piping (hard pipe) – Common Components Subsea
Plugged/Choked 1 critical failure registered for 88 units.
Pressure and volume regulator (PVR) 89 OREDA-24 Component = Valve,
Control Plugged/choked 4 failures registered for 69 units. 75% of the failures are regarded as critical.
Control System
Topside Master Control Station 24,5 OREDA-24 Subunit = Master Control
Station (Topside)
Control/signal failure Erratic output Fail to function on command Spurious operation Unknown
54 failures registered for 9 units. 56% of the failures are regarded as critical.
Assumed that the MTTF is representative of one Master Control Station with internal redundancy. The critical failures represents the loss of redundancy.
Wet Mate Connector
72022
Reliability of Subsea Harness Systems including Wetmate Connectors – Teledyne D.G.O’Brian ODI Cable Termination Reliability study Reliability Analysis of Wet-Mate Nautilus Connectors Reliability Analysis of Wet-Mate Hybrid Connectors
- Critical
Pressure-Balanced Oil-Filled (PBOF) Hose Assemblies (Jumpers or Harnesses) terminated with wetmate connectors has been assessed. The data 3,17 FIT (10-9) has been divded in two, one half for the wet mate connector and one half for the jumper
3836 - Critical General ODI cable terminations
22427 - Critical ODI’s Wet-Mate Nautilus Connector
1638 - Critical ODI’s Wet-Mate Rolling Seal Hybrid Connector
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Component Name MTTF Data Source OREDA Filter Failure Modes Comment
380 OREDA -24 Component = Power/Signal Jumper
Control/signal failure Short circuit Transmission
10 critical failures registered for 775 units.
Electrical Dry Mate Connectors 4424 Data for wet-mate
connectors - -
It is assumed that the dry mate connections are more reliable than wet mate connections. An estimated 1/3 of the average failure rate for wet mate connectors has been used to estimate the failure rate of dry mate connectors
Electric Jumpers
300 OREDA -24 Reliability of Subsea Harness Systems including Wetmate Connectors – Teledyne D.G.O’Brian
Component = Power/Signal Jumper
Control/signal failure Short circuit Transmission
10 critical failures registered for 775 units.
72022 - Critical The data 3,17 FIT (10-9) has been divded in two, one half for the wet mate connector and one half for the jumper
Junction boxes/ Splitter boxes 41
Data from Telecordia, supplied by Aker Solutions Controls Department in Aberdeen
- Critical Failure Rate Data Source: Mil-Hdbk-217F for resistors, capcitors, and inductive devices, transformers
Magnetic Bearing Control Module 6,3
S2M – MTTF report for topside MBCM system
- Critical
The magnetic bearing system has been evaluated by vendor and the failures have been split in to failures in control pod and failures in compressor. Approx. 98.9% of the MTBF stated in report is caused by control failures (not taking into account jumpers and connectors)
Anti-surge / Compressor Control pod 38.7
ICS Triplex. Control function description. Doc. No 6592PF-CFD-REV4
- Critical -
SCM 43 (one SEM) OREDA-24
Subunit = Subsea Control Module Component = Subsea electronic module
Control/signal failure Fail to function on demand Insufficient power Other Short circuit Spurious operation
A single SCM contains 3 separate dual SEMs (one part is powered by the UPS A and the other by UPS B): - PCS SEM - PSD SEM - CM SEM (non redundant, but considered to be not critical) Data for two dual SEMs (A and B) are used to estimate the failure data for an all electric subsea control module. OREDA-24 gives 27 failures for 263 units, whereof 85% critical failures.
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Component Name MTTF Data Source OREDA Filter Failure Modes Comment
Failure rate for one SEM: 2,669 x106
Failure rate of one redundant SEM: 2x106
(including common cause failures) Failure rate for two SEM (each redundant): 4x106
UPS 8.1 Engineering judgement - -
The UPS contains a battery, a SEM, AC/DC converters, an internal controller and transformers. Based on engineering judgement (given a MTTF of 42 years for a SEM and 10 years for a battery) it is assumed that the MTTF of the UPS will be about 8 years
HV Power System
Topside Main Circuit Breaker 1116
OREDA 2002, tax 2.2, page 334
- Critical Data for cicuit breaker in eletric motor. Based on critical failures UST, circuit breaker 0,36% of the failures 28.44 E-06.
Topside Transformers 554
Vetco Gray RAM analysis report. 37-1Y-VET-F15-00001, rev.02
- Critical Data for topside transformers assumed to be at least as good as the data supplied by Vetco for the main subsea step-down transformer.
VSD 6.105
Alstom. RAM Prelim Analysis. File no. 4MVE0036_C
- Critical -
10.67 SPC Project. System RAM Analysis - Critical
Topside Umbilical Hangoff 358 OREDA-24
Subunit = Static Umbilical
(OREDA-24has zero registered failures for dynamic umbilicals including termination units, use static umbilical as filter instead)
No registered failures
Assume ½ critical failure in the next operational year
Power Umbilical 108 OREDA-2002. pg. 811 Subunit = Static Umbilical
Critical and degraded
OREDA-24 has registered 22 registered failures for a static umbilical, out of which 17 failures are related to the hydraulic lines. There are no hydraulic lines in the power umbilical only 3 off power cores and 1 fibre optic line with 3 bundels à 16 fibres. For the power cables there are only degraded failures registered, however, for the power cores
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Component Name MTTF Data Source OREDA Filter Failure Modes Comment
there is no redundancy. It is therefore assumed that the degraded failure of a control umbilical power line will be critical for the power umbilical.
Failure rate P/S line: 0,34x106
Failure rate power cores: 0,34 x106 x 3
Due to the high number of internal power cables it is assumed that the only critical failure of the umbilical is related to common cause failures of the power/signal lines. A common cause factor of 10% is assumed for the power/signal lines
Degraded failure rate P/S line: 0,34x106 Common Cause failure P/S lines: 0,034 x106
Umbilical Termination Assembly (UTA) 310 OREDA-24 Subunit = Static Umbilical No registered
failures Assume ½ critical failure in the next operational year
Subsea Enclosures (Transformer)
675 (two
connectors) OREDA-2002. pg. 804 Connector – Common
Components Subsea External Leakage Other
There are no failure data registered for subsea enclosures. External leakage is assumed to be the critical failure. It is further assumed that the leakage points will most likely be through the connection/flange points. In order to find data it has been decided to compare the leakage rate for an enclosure to the leakage rate from 2 subsea mechanical connectors. 3 failures registered for 606 units. Only 1 failure registered as critical. Critical failure rate is thus 1/3 of total failure rate
Subsea Main Step-down Transformer 554
Vetco Gray RAM analysis report. 37-1Y-VET-F15-00001, rev.02
- Critical
It was decided to apply the data from the DNV analysis for the transformers as the source seems to be more appropriate since Vetco Gray supplies the transformer for OL. The failures caused by the marine environment are reflected through the failure rate of the subsea enclosures.
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Component Name MTTF Data Source OREDA Filter Failure Modes Comment
HV Penetrator/ Dry connector 192 Data received from
Deutch - Critical Data for 18/30 (36)kV 900A Dry mate connectors
HV Power Jumper 100
Engineering judgment from the Ormen Lange project, in cooperation with Statoil and DNV
- - The engineering judgment assumed an MTTF of 100 years per component, i.e. the jumper, connector and penetrator.
HV Wet Mate Connector
77 (female)
Data received from Deutch
-
Critical Data for female part of wet mate connector 18/30 (36)kv 900Amp. Most complex part of connector
154 (male)
Data for male part of wet mate connector 18/30 (36)kv 900Amp. Least complex part of connector
Appendix F – Preliminary report The preliminary report is quite short and was written more as an aid to the author, than to the supervisors. This has been done in agreement with the supervisors. The master has evolved from the eight main tasks described in the preliminary report, but is still focused towards these as the main targets.
NTNU
Preliminary study report Design for reliability – Applied to development of subsea process systems
Ingrid Almås Berg 1/2/2010
1. Project description This thesis is a part of the master degree study in Production and Quality engineering at NTNU, Norwegian University for Science and Technology. It is meant to be carried out as an in-depth literature study during the spring semester 2010, valuing 30 ECTS. A part of the thesis is a suggested methodology and case study, based on the findings in the literature study. This preliminary report is written to describe the project tasks, the targets of the project and to gather thoughts on how to manage the project. It has been carried out early in the spring semester before the main part of the project and changes may occur as the project continues. The preliminary report is meant to give a better knowledge of the problem and the tasks, defining work methods and giving an outline of the work packages.
1.1 Problem description The subsea power and process department at Aker Solutions is working to create innovative processing solutions within the oil and gas industry. For the operation of a subsea system the reliability is crucial. From the early design phases and through the whole lifetime of a system, the product performance must be addressed properly. Relevant methodologies and practices for reliable product design shall be studied in this thesis, as well as a discussion of their application. A product’s full life cycle shall be considered and a methodology for a subsea process system developed. This methodology will subsequently be applied to the development of a specific process sub-system.
1.2 Objective The project objectives can be divided in five tasks:
1. Perform a literature study on the application of different methods for design for reliability. The literature study should cover, and discuss, methods normally applied across relevant industries.
2. Familiarise with systems and main equipment used within subsea process industry. 3. Based on learning from the literature study discuss and summarise the main factors that
contribute to unreliability. Describe challenges for the subsea process industry in particular. 4. Suggest and develop a methodology for reliability performance and specification throughout
five defined stages of a Product Life Cycle (Front-end, Design, Development, Production and Post-Production) of a typical Subsea Process System. Special attention should be paid to the 3 first phases.
5. Perform a case study to evaluate the applicability of the suggested methodology for a chosen stage of the life cycle. The case study should be applied to a chosen sub-system within a typical subsea process system.
2. Work methods
2.1 Project management - Preliminary report defining main objectives, activities and time frame. - Continuous evaluation of time frame and finished activities.
2.2 Literature survey material - Databases and articles - Books written on the subject - Norms, regulations and standards
2.3 Reports and written work - Preliminary report - Literature study on reliability, methods for design for reliability and unreliability - Methodology for reliability performance and specification throughout a product life cycle - Case study results
2.4 Framework conditions The master thesis was handed out the 18th of January, 2010, and shall be handed in the 14th of June. The assignment has a value of 30 credits, 100% of one semester, equalling 48 working hours per week.
1
Preliminary study and report Task: To study the assignment and its tasks, and to write a report on the problem solving process. Objective: To get an understanding of the project assignment and how to approach the problem, and to plan the project work. Content:
- Problem description - Objectives and tasks - Description of activities - CTR
Literature: Rolstadås, A, 2001, “Praktisk Prosjekt Styring”, ISBN 82-519-1652-6 Work method: Project Challenges:
- Limiting the report - Separate the project activities/tasks - Make a timeframe for each activity
Deliverable: A report consisting of task descriptions, a time frame, work methods and thoughts on how to attack the problems. Duration: Start: 20.01.2010 Finish: 4.02.2010
2
Design phases Task: Describe the five defined stages of a Product Life Cycle (Front-end, Design, Development, Production and Post-Production). Objective: To understand and describe the different stages of a Product Life Cycle. Content:
- An overview of the different stages of a Product Life Cycle. - Examples of a product in the different stages
Literature: - Murthy, Rausand and Østerås, 2008, “Product Reliability – Specification and Performance”,
ISBN 978-1-84800-270-8 - Information from Aker Solutions - Articles, books and standards
Work method: - Literature study - Finding main aspects of different stages - Make examples based on a product, preferably equipment used in the subsea process
industry. Challenges: To properly describe the different stages and to exemplify them through a products life cycle. Deliverable: A description of the different stages of a product life cycle. Duration: Start: 12.03.2010 Finish: 26.03.2010
3
Reliability –concept, history and basics Task: To study the concept and background for reliability engineering. Objective: To identify the meaning of reliability, why it is considered necessary and how it is applied across industries. Content:
- Definition of term - Brief history - Identification of use - Identification of mathematical use
Literature: - Dictionaries and encyclopaedias - Murthy, Rausand and Østerås, 2008, “Product Reliability – Specification and Performance”,
ISBN 978-1-84800-270-8 - Blishke and Murthy, 2000, “Reliability”, ISBN 0-471-18450-0 - Rausand and Høyland, 2004, “System Reliability Theory”, ISBN 0-471-47133-X - Calculus and statistics books - Articles
Work method: - Study and analysis of literature - Discussions with supervisors - Report writing - Literature discussion
Challenges - To find definitions - Identifying trustworthy internet information - Finding good and sufficient sources
Deliverable: A presentation of the concept reliability and its basic use in engineering Duration: Start: 18.01.2010 Finish: 19.02.2010
4
Methods for design for reliability Task: Identify and discuss different methods for design for reliability and their application. Objective: To describe and analyse how different methods for design for reliability are used in industry. Content:
- Identification of different methods for design for reliability. - Analysis of the application of the methods. - Comparison of the different methods.
Literature: - Murthy, Rausand and Østerås, 2008, “Product Reliability – Specification and Performance”,
ISBN 978-1-84800-270-8 - O’Connor, 2002, “Practical Reliability Engineering”, ISBN 0-470-84463-9 - Books and articles concerning the subject - Standards
Work method: - Literature study - Analysis of literature - Discussion with supervisors - Discussion of literature and report writing
Challenges: - Finding relevant literature - Identifying main method procedures and application - Identifying differences between the methods
Deliverable: An overview of different methods for design for reliability, including their application and a discussion of their use in relevant industries. Duration: Start: 18.01.2010 Finsih: 05.03.2010
5
Systems and main equipment Task: Familiarise with systems and main equipment used within subsea process industry. Objective: To get an overview and an understanding of the different equipment and systems used by the subsea process industry. Content: Examples of systems and equipments presented in relation to different subjects presented in the thesis. Literature:
- Sangesland S., 2007, “Subsea Production Systems”, Course TPG4200, NTNU. - Work in-house at Aker Solutions
Work method: - Study of the different systems and equipment - Development of examples for the thesis
Challenges: To present the material in a context. Deliverable: Examples and other information used together with the different subjects presented in the thesis. Duration: Start: 19.01.2010 Finish (literature study): 26.03.2010 Finish: 6.06.2010
6
Factors contributing to unreliability Task: Discuss and summarise the main factors that contribute to unreliability. Describe challenges for the subsea industry in particular. Objective:
- To identify the factors contributing to unreliability. - To analyse the factors that may have an impact on the subsea industry.
Content: - Definition of unreliability - Analysis of different contributors to unreliability - Identification of the challenges related to unreliability in the subsea industry
Literature: - Articles - Books - Previous literature study on reliability - Previous project work
Work method: - Further study of information found while working on the previous activities - Identifying factors - Analysis of challenges
Challenges: To see how unreliability can occur and which effects it can have. To understand what challenges are the most pressing in the subsea industry. Deliverable: A presentation of different contributors. A discussion of the origins and effects of unreliability contributors. An identification of challenges occurring in the subsea industry. Duration: Start: 18.01.2010 Finish: 12.03.2010
7
Methodology for reliability performance and specification Task: Suggest and develop a methodology for reliability performance and specification throughout five defined stages of a Product Life Cycle of a typical Subsea Process System. Objective:
- To develop a methodology for reliability performance and specification. Content:
- Presentation of a methodology developed for the thesis. Literature:
- Rausand M & Høyland A, 2004, “System Reliability Theory”, ISBN 0-471-47133-X - Murthy, Rausand and Østerås, 2008, “Product Reliability – Specification and Performance”,
ISBN 978-1-84800-270-8 - Articles - Books - Other methods
Work method:
- Literature study - Analysis of existing methods in combination with previously discussed challenges for the
subsea industry - Development of a methodology - Discussion of the methodology
Challenges: - To find suitable methods for the different stages of a product life cycle. - To identify the measures needed to answer the challenges for unreliability. - To develop a methodology including all necessary methods
Deliverable: - A methodology for reliability performance and specification suitable for the development and
use of a subsea process system. Duration: Start: 06.04.2010 Finish: 23.04.2010
8
Case study Task: Perform a case study to evaluate the applicability of the suggested methodology for a chosen stage of the life cycle. The case study should be applied to a chosen sub-system within a typical subsea process system. Objective: To study how the chosen methodology works for a chosen stage of the life cycle. Content:
- Presentation of the case study - Analysis of the results found in the case study.
Literature: - N/A, work will be carried out in-house at Aker Solutions
Work method: - Perform a case study - Analysis of results - Discussion and evaluation of the applicability of methodology
Challenges: To find a suitable tool for the case study. To understand the results of the case study in connection with the choices made for the methodology. Deliverable: An evaluation of the methodology based on the results from a case study. Duration: Start: 23.04.2010 Finish: 26.05.2010