reliability levels of subsea production systems during operations
TRANSCRIPT
Working together for a safer world
How to control reliability levels of subsea production
systems during operations?
Inge Alme
February 2015
Reliability levels of subsea systems in operation
Reliability of subsea systems
• High requirements to availability of the
systems to be able to achieve the necessary
production rate
• The reliability of the systems is typically
analysed during the design phase, given certain assumptions and operational
parameters
• High reliability is also a condition for high safety level and low environmental risks
• Design is optimized to achieve the necessary reliability levels, i.e. high degree of
redundancy of critical components and important barriers.
Reliability levels of subsea systems in operation
Decision making in the operations
• What happens if a component failure is detected during operations?
• Is the information in the technical specification sufficient for important insights?
• How critical is the failure?
• How will the failure affect the current reliability level?
• Do we need to stop the production?
• Do we need to inspect and/or repair the equipment/components that have failed?
• What happens if a periodical test interval for a critical safety function is extended?
• How will the extension affect the availability of the function?
What is the basis for these critical decisions that have to be made by the operators?
Reliability levels of subsea systems in operation
Experiences from other industries
• Nuclear industry
• Pressure from US regulators in the 90’s pushed the
development of risk monitors to be used to get updated
picture of risk as input to maintenance planning
• The use of risk informed approaches allows both regulator
and the industry to focus on important safety issues
• INPO Performance Indicator Index from 1995 to 2004 for US
plants shows that plants with risk informed decision making activities have increased profitability with no degradation in
safety compared to other plants
• Deepwater drilling industry
• Significant focus on risks related to BOPs after Macondo
• A BOP risk model developed and implemented on some rigs
Reliability levels of subsea systems in operation
BOP Risk Model
Reliability levels of subsea systems in operation
BOP Risk Model Interface
Reliability levels of subsea systems in operation
How could this look like for other subsea systems?
Input from design (FMECA, SIL,
documentation, RAM studies etc.)
Requirements from regulations,
standards, rules, etc.
Input from
operations, incl. barrier strategy,
operational
philosophy, etc.
Automatic input from control
system
Manual input from operators
Live reliability model for subsea
systems
Reliability levels of subsea systems in operation
Calculation of ‘real time’ reliability level (Safety Integrity Level) of the
critical functions
Reliability levels of subsea systems in operation
Use of operational data
• The model can use generic data
• The generic data can be updated when enough specific data is available, e.g. enough events in the event history
Data update
Reliability levels of subsea systems in operation
Take into account the test interval of components
Reliability levels of subsea systems in operation
The importance of the different components
• The operator will continuously be able to check which components that are the most
important (or vulnerable)
Reliability levels of subsea systems in operation
Implementation of a live risk model
Operational staff use the risk model, updating the
ONLINE event history daily
Staff in the system owner’s offices, Oil company offices,
and regulator offices use risk model for Planning,
viewing, and other applications
Backups are made continuously the same way as for
all other files on the server
Technical support for software, risk model update, etc.
Reliability levels of subsea systems in operation
The benefits of risk modelling of subsea systems
• Real time monitoring risk qualitatively and quantitatively
• Input to better design solutions
• Calculating Allowed Outage Time and cumulative risk
• Decision support in critical situations
• Planning of maintenance outages to reduce risks
• Long term risk profiling
• Analysis of cumulative risk
• Evaluation of unplanned events
• Training
• Feedback – lessons learnt
Lloyd’s Register and variants of it are trading names of Lloyd’s Register Group Limited, its subsidiaries and affiliates.
Copyright © Lloyd’s Register [Entity]. 2014. A member of the Lloyd’s Register group.
Inge Alme Global Account Director Lloyd’s Register Group T +47 928 86086 E [email protected] Lloyd’s Register Group 71 Fenchurch Street, London EC3M 4BS
Working together for a safer world