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Age of concern

Petroleum installations on the NCS are getting steadily older. The big issue is how long they can continue to operate safely.


This article was published in the publication "Safety - status and signals 2009-2010".

Installations still in action
At 31 December 2009, the PSA had issued consents to extend production life for the following installations:
(The year in brackets refers to when the consent was given.)

  • Åsgard C (2005) to 2018
  • Ula (2005) to 2028
  • Ekofisk 2/4-B (2006) to 2028
  • Statfjord A (2007) to 2028
  • Valhall QP, PCP and DP (2007): QP to 2010, PCP and DP to 2015
  • Hod (2008) to 2015
  • Norpipe oil pipeline (2008) to 2028
  • Gyda (2009) to 2030
  • Veslefrikk A and B (2009) to 2020
  • Ekofisk (2009):
    • - 2/4-H and 2/4-Q to 1 September 2013
    • - 2/4-C (as part of evacuation route) to 1 September 2013, then pursuant to the regulations for simpler installations without quarters to 2028
    • - 2/4-FTP to 31 December 2015
    • - 2/4-BS01, 2/4-W and 2/4-SF to 31 December 2012
    • - 2/4-A to 31 December 2016,
    • - eight-inch flowline between 2/4-C and 2/4-B to 2028
    • - 12-inch water injection flowline from 2/4-K to 2/4-W to 31 December 2012, then diverted to another installation to 2028.
  • Norpipe gas pipeline and B11 (2009) to 2028


 

A great many Norwegian offshore structures are getting long in the tooth. Roughly half of them have already exceeded their original design life.

Another 25 – including fixed platforms, floating installations and pipelines – will be passing the same point over the next decade.

New technology and operating methods as well as improved oil and gas recovery methods mean that licensees often want to keep these units working past the date they were due to retire.

In many cases, continuing to use facilities beyond their design life makes socioeconomic sense. But it is not acceptable that such extensions are allowed at the expense of safety.

“An aging installation must be as safe as a new one,” says Gerhard Ersdal, head of the PSA’s project for extending production life. “We can’t accept that it’ll be more dangerous to work on such units.”

Outdated
But keeping an old facility going is not straightforward. Metal can corrode, structures weaken and systems become outdated.

In many cases, work-related challenges such as noise, vibration and ergonomics will be faced. Expertise and working procedures can become outmoded.

The probability of failure for components, structures and systems also increases with age. And a gap can develop between a unit’s actual condition and today’s regulatory standards for design, technology, systems and the working environment.

That poses questions of where to draw the line, and of how long it is possible to rely on safety being sufficiently well maintained.

Knowledge
The number of old installations on the NCS has increased steadily since the 1990s, and so has knowledge about the issues they present.

Extending production life has been a main priority at the PSA since 2006. A multidisciplinary project team has worked to identify the aspects of aging which reduce safety on an installations.

One goal is to establish criteria and frameworks for extending production life, both by developing regulations and by ensuring that the industry develops good standards and routines.

Another reason for making this a main priority has been to increase awareness of the issue with government agencies and industry players.

“Little knowledge about extending production life was available when we started, while common standards and clear procedures were also lacking,” says Mr Ersdal.

Consent
A regulatory requirement was introduced in 2002 that an operator needed official consent to use an installation beyond the production life specified in the original plan.

When applying for such approval, the operator must analyse and assess the HSE aspects of the activities and unit concerned, and specify measures to be taken as a result of these evaluations.

At the PSA’s request, the OLF initiated extensive work in 2006 to develop a standard for extending production life. One outcome is a set of guidelines on preparing an application to continue using an installation.
The OLF has also developed checklists, guidelines and proposals for Norsok standards in such areas as support structures, transport and subsea systems.

Other topics covered include drilling and well technology, risk management, technical safety systems and the working environment, and process and utility system.

The PSA has collaborated with a number of Norwegian and international research institutions to build expertise on the challenges posed by installations past their design age.

Important
An extensive study by the Sintef research foundation has made important proposals about how the challenges related to safe production life extensions should be handled.

This work aimed to collect and systematize existing information on aging and extending production life in order to identify relevant issues.

A number of findings from the investigation play a key role in the supervisory methodology currently applied by the PSA in this area.

Sintef looked at well integrity, process and technical safety, subsea installations, pipelines and maintenance of aging installations.

“The study gives an integrated picture of what aging actually involves, and good advice on how we should deal with the challenges,” says Mr Ersdal. “That includes physical condition, becoming outmoded and organisation.”

Maintenance
In collaboration with Sintef, the PSA carried out a study to identify how aging and extending production life affect maintenance management.

This survey was pursued with field operators ConocoPhillips, Talisman and BP as well as rig contractors Songa and Dolphin.

Their responses exposed a number of consequences, such as an increased scope of maintenance work and the need to pay greater attention to continuous improvement and maintenance efficiency.

Maintenance strategies very often need to be changed, too, while older installations require more modifications and replacements.

The operators identified aging mechanisms such as corrosion, loss of coatings, deposition in process equipment and subsidence of fixed platforms as the biggest maintenance challenges.

Other key issues are access to spare parts for old equipment and systems, and hardware which becomes outdated long before its design life is over.

Robust
Safety barriers, both technical and operational, will often need to be made more robust on an aging installation.

Another important requirement is to secure the expertise needed to operate and maintain old equipment and systems, and to ensure that these are compatible with new solutions.

Working past “retirement age” means that the operator must know in detail what has to be done to maintain safety.

With good management, it is fully possible to keep installations in a satisfactory condition.

By Øyvind Midttun