A large part of the Norwegian gas and oil production facilities has reached their initial design life, but the respective fields are still producing substantial levels of hydrocarbons. In order to ensure technical and operational integrity of these ageing facilities the Norwegian oil industry Association (OLF) has initiated a project to establish the necessary standards and guidelines for assessing and ensuring safe life extensions. This paper presents this project and the headlines of these standards and guidelines.

1. Life Extension of Aging
Petroleum Production
Facilities Offshore
Per Otto Selnes, M.Sc.
Manager Operations
Norwegian Oil Industry Association
www.olf.no
Contributor:
Gerhard Ersdal, Ph.D.
Principal Engineer
Norwegian Petroleum Safety Authority

2. Introduction
• A large part of the Norwegian gas and oil production facilities
have reached their initial design life, but the respective
fields are still producing substantial levels of hydrocarbons.
• In order to ensure technical and operational integrity of
these ageing facilities the Norwegian oil industry Association
(OLF) has initiated a project to establish the necessary
standards and guidelines for assessing and ensuring safe
life extensions.

3. Background
Technical and operational integrity of
offshore facilities on the Norwegian
Continental Shelf (NCS) is important
for:
• the safety, health and welfare of
offshore employees and their families
• not harming the environment
• making sure that the owners get no
interruption of their revenues, nor do
the government and the citizens of
the country

4. Complex issue

5. Age vs status on application for consent
• Number of installations on the NCS excl. pipelines: 103
• Number of consents expiring by end 2015: 44
• Number of new consents given (Incl. 1 expiring 2015): 26
• Number of applications being prepared / handled: 7
• Number of applications due? 1
• Number of installations shut down: 2
• Removed/disposed of, additional to the 103 5
• Disposals approved 7

6. Norwegian pipelines
First installations (year) 1971
Total number of items in database : 920
Cumulated length of large pipelines (km): 6 100
Large variations in length, size and design life
Lengths: 23 km - 1 200 km
Diameter (inches): 1’’ – 44’’
Design lifetime (years) : 5 - 50

7. Scope of work
Work divided in two:
• Firstly to develop and issue recommended
guidelines, outlining a proposal for the
preparation of the application of a new
consent;
• Then to develop tools necessary to assess
continued safe operation.
Split in the following areas:
• Risk management
• Working environment
• Structural integrity
• Technical safety systems
• Drilling & well systems
• Top side process & utility systems
• Transport systems (pipelines etc.)
• Sub sea systems

8. Consent Applications for
Lifetime Extension of Facilities
Scope of the OLF guideline for assessments and preparation of applications
OLF guideline
Main Document
No. 122
Published in June 2008
Sub- Documents
Drilling and Well Drilling systems and Well
Permanente structures Offshore integrity, including
Structures Systems conductors, BOP and down
Check List hole equipment
Published May 2008
Published in May 2008
Transport Process
Export and intra field
Pipelines and risers. Systems Systems
Emergency Shutdown, Evacuation, Technical Safety Underwater
Barriers, Fire and Gas Detection and other Systems,
safety systems. installations
Living Quarters, Escape Ways, Material ,Working
and Chemicals Handling , Control Rooms,
Man machine interfaces. Environment and
Risk management
Consent Applications for Life Extension of Facilities are submitted to the Petroleum
Safety Authority (PSA) Norway and Norwegian Petroleum Directorate (NPD).

9. Deliveries

10. Guideline for the assessment and documentation
of service life extension of facilities
Three chapters
• Outlines a proposal for the preparation of the application
of renewed consent required prior to use of a facility
exceeding the current consent period
• The guideline identifies how the operators can assess and
document safe operation of facilities for an extended
period
• Facilitate the preparation the Application for Consent for
Life Extension
Start early
• It is recommended to start the evaluation and application
process at least two years prior to the expiry of the current
consent period

11. Technical Safety Systems and
Working Environment
Risk Management
• Gives detailed comments and
recommendations for the assessment of
facilities concerning the areas outlined
– recommends Quantitative Risk Analysis
(QRA) and necessary sensitivity studies
to be updated addressing the scenario
and operating conditions envisaged
during the life extension period
– Evaluations of factors that may be
expected to change over time should be
included in the sensitivity evaluations.

12. Technical Integrity
• Normally it is possible to safely operate an installation
beyond its calculated fatigue life by using the inspection
results available
• For structural details that can not be inspected,
recommendations are given in the standard.
• Piles securing the installation to the sea bed are an
example of such structural elements
• Specific requirements to design fatigue factors for
calculation of fatigue damage from driving are given,
based on driving records

13. Structural Integrity for Existing
Offshore Load-Bearing Structures
New Norsok Standard
• NORSOK N-006 standard gives requirements
for assessment of the structural integrity of
offshore structures in-service and for life
extension
• NORSOK N-006 is applicable to all types of
offshore structures used in the petroleum
activities, including bottom founded structures
as well as floating structures.

14. Drilling & Well Systems
Checklist has been established
• General considerations and requirements:
– Brief status on drilling facilities & wells
– Main degradation mechanisms and corresponding
control measures relating to “Safety Critical
Equipment”
– Well integrity situation and potential changes in the
related risk-picture
– Potential well stimulation, intervention & work over
methods/ limits
– Future activity level and modification plans
– Future capabilities required to monitor, access,
operate, maintain and abandon drilling- and well
facilitiesCondition of utility systems to support future
D&W activities
– Future capabilities to serve for potential “tie-ins” and
specific measures for enhanced petroleum recovery
in the area

15. Top Side Process and Utility Systems
A list of systems that should be
addressed during assessing life
extension of top side’s process and
utility systems has been established
• Containing “common factors” to be
considered when evaluating the
integrity of process and utility
systems.
– Have conditions changed from when
the system was designed?
– Will future operations still be within
the capabilities of the system?
– Could specific studies be required
(list typical studies for individual
systems)

16. Transport and sub sea systems
Norsok standards
Transport Systems (Pipelines Etc.)
• The transport system in this context is facilitating transport through
pipelines, risers and loading hoses intra-field, inter-field and as trunk
pipelines to shore and onshore.
Sub Sea Systems
• Subsea systems are increasingly used on
the Norwegian Continental Shelf and
this standard is prepared
to support the process of assuring
technical integrity of the sub sea
system and its elements beyond
the original approved
service life.

17. Conclusion
The guidelines, standards and
checklists developed through
this project will provide
valuable assistance to
offshore facility owners and
authorities when assessing
the condition of aging
facilities, and if they can be
safely operated for a new
consent period.